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11,200 | Prognostic implications of arrhythmias during primary percutaneous coronary interventions for ST-elevation myocardial infraction. | The authors reviewed current knowledge on occurrence, clinical and prognostic significance, and management of sustained ventricular arrhythmias, atrial fibrillation and bradyarrhythmias in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary interventions (PCI). Cardiac arrhythmias worsen clinical course and prognosis in patients with ST-elevation myocardial infarction undergoing primary PCI. Sustained ventricular arrhythmias developing during or early after PCI and associated with mechanical restoration of coronary flow and reperfusion do not affect mortality, whereas those related to incomplete revascularization and ongoing ischemia are associated with poor prognosis. New-onset atrial fibrillation increases mortality and stroke rates in patients undergoing primary PCI. Among bradyarrhythmias, high-degree atrioventricular block is associated with short- and long-term mortality. Prompt and complete revascularization is the cornerstone of arrhythmia management. Arrhythmias related to reperfusion do not usually require specific treatment, whereas those because of ongoing ischemia, incomplete revascularization and presence of substrate require adequate management including nonpharmacological and pharmacological therapies. |
11,201 | Monomorphic ventricular tachycardia originating from right ventricular outflow tract as a trigger for the recurrent ventricular fibrillation in a patient with brugada syndrome. | Brugada Syndrome is a cardiac ion channel disorder that affects the sodium current. This syndrome is characterized by cove-shaped ST elevation in ECG leads V1 to V3 in the absence of structural heart disease.</AbstractText>A 36-year-old man diagnosed with Brugada Syndrome was reffered to our center with frequent implantable cardioverter-defibrillator (ICD) discharges. ICD interrogation showed several appropriate ICD intervention for tachycardia detected in the ventricular fibrillation zone. Unfortunately, quinidine was not available in our country at the time of admission; therefore, we decided to ablate suspicious arrhythmogenic substrates. Programmed ventricular stimulation from right ventricle (RV) reproducibly induced a sustained ventricular tachycardia with left bundle branch block morphology and inferior axis. RV outflow tract (RVOT) endocardially mapped and earliest activation signal (90 milliseconds) achieved at posterior aspect of the RVOT septum. RF energy application at that site terminated the tachycardia and no inducible tachycardia was detected. During two-year follow-up, he had no episodes of ICD therapy and remained symptom-free with any antiarrhythmic drug.</AbstractText>This case clearly indicated that catheter ablation might be considered as a viable option in every patient with Brugada syndrome and frequent ICD discharge. During the electrophysiology study, intravenous procainamide may also be used to reveal future arrhythmogenic focus in this group of patients.</AbstractText> |
11,202 | Current status of primary prevention of sudden cardiac death with implantable cardioverter defibrillator in patients with chronic heart failure--a report from the CHART-2 Study. | The current status of primary prevention of sudden cardiac death (SCD) with implantable cardioverter defibrillator (ICD) in patients with heart failure with reduced ejection fraction remains to be fully elucidated in Japan.</AbstractText>In the chronic heart failure (CHF) cohort study, the CHART-2 Study, we enrolled 2,778 consecutive patients with NYHA class II-III. According to the Japanese Circulation Society guideline of prophylactic ICD, we divided them into 3 groups: group A, class I indication; B, class IIa; and C, no indication. During the (median) 3.2-year follow-up, 79 fatal arrhythmic events (FAE), defined as composite of sudden cardiac/arrhythmic death, ventricular tachycardia/fibrillation and appropriate ICD therapy, occurred. In the groups A, B and C, the prevalence of FAE was 16.1%, 8.9% and 1.9%, respectively; the use of prophylactic ICD among those with FAE, however, was only 44%, 9% and 6%, respectively. In the groups A and B combined, chronic atrial fibrillation (cAF) and left ventricular end-diastolic dimension (LVDd) ≥ 65 mm were independent predictors of FAE, and, when combined, their prognostic impact was highly significant (hazard ratio, 7.01; P<0.001).</AbstractText>Primary prevention of SCD with ICD in CHF patients is validated but is still underused in Japan, and the combination of cAF and LVDd ≥ 65 mm may be a useful indication of prophylactic ICD implantation.</AbstractText> |
11,203 | The protective effects of a phosphodiesterase 5 inhibitor, sildenafil, on postresuscitation cardiac dysfunction of cardiac arrest: metabolic evidence from microdialysis. | Recent experimental and clinical studies have indicated the cardioprotective role of sildenafil during ischemia/reperfusion injury. The aim of this study was to determine, by obtaining metabolic evidence from microdialysis, if sildenafil could reduce the severity of postresuscitation myocardial dysfunction and lead to cardioprotection through beneficial effects on energy metabolism.</AbstractText>Twenty-four male piglets were randomly divided into three groups: sildenafil (n = 8), saline (SA; n = 8) and sham operation (n = 8). Sildenafil pretreatment consisted of 0.5 mg/kg sildenafil administered once intraperitoneally 30 minutes prior to ventricular fibrillation (VF). The myocardial interstitial fluid (ISF) concentrations of glucose, lactate, pyruvate, glutamate and glycerol were determined by microdialysis before VF. Afterward, the piglets were subjected to 8 minutes of untreated VF followed by 15 minutes of open-chest cardiopulmonary resuscitation. ISF was collected continuously, and the experiment was terminated 24 hours after resuscitation.</AbstractText>After 8 minutes of untreated VF, the sildenafil group exhibited higher glucose and pyruvate concentrations of ISF and lower lactate and glutamate levels in comparison with the SA group, and these data reached statistical significance (P < 0.05). Advanced cardiac life support was delivered to both groups, with a 24-hour survival rate showing a promising trend in the sildenafil group (7 of 8 versus 3 of 8 survivors, P < 0.05). Compared with the SA group, the sildenafil group had a better outcome in terms of hemodynamic and oxygen metabolism parameters (P < 0.05). Myocardial tissue analysis revealed a dramatic increase in the contents of ATP, ADP and phosphocreatine in the sildenafil group versus the SA group at 24 hours after return of spontaneous circulation (ROSC; P = 0.03, P = 0.02 and P = 0.02, respectively). Furthermore, 24 hours after ROSC, the sildenafil group had marked elevations in activity of left ventricular Na(+)-K(+)-ATPase and Ca(2+)-ATPase compared with the SA group (P = 0.03, P = 0.04, respectively).</AbstractText>Sildenafil could reduce the severity of postresuscitation myocardial dysfunction, and it produced better clearance of metabolic waste in the ISF. This work might provide insights into the development of a novel strategy to treat postresuscitation myocardial dysfunction.</AbstractText> |
11,204 | Incidence, definition, diagnosis, and management of the cardiac resynchronization therapy nonresponder. | Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with mild-to-severe heart failure. However, up to 40% of CRT recipients are nonresponders. This review addresses important aspects with regard to the identification and management of CRT nonresponders.</AbstractText>Mid-term clinical or echocardiographic nonresponse is associated with worse clinical outcomes during the extended follow-up. A number of predictors are indicative of CRT response, which include patient characteristics, electrical determinants, and imaging techniques from preimplant to postimplant period, and can be grouped as modifiable and nonmodifiable contributors to treatment response. Advanced age, male sex, ischemic cause, end-stage heart failure, inadequate electrical delay, and absence of mechanical dyssynchrony are regarded as unfavorable but nonmodifiable factors, for which considering underutilization of CRT by refining patient selection is reasonable. On the contrary, more efforts should be made to optimize patient management by correcting those modifiable factors, such as suboptimal medical therapy, uncontrolled atrial fibrillation, left ventricular lead dislodgement or inappropriate location, loss of biventricular capture, and lack of device optimization.</AbstractText>Proper management and careful selection of CRT recipients will transform a proportion of treatment nonresponders into responders, which is vital to improve patients' outcome.</AbstractText> |
11,205 | Heart failure with preserved ejection fraction. | Many patients with heart failure (HF) have a normal left ventricular ejection fraction, and are labelled as having HF with preserved left ventricular ejection fraction (HFPEF). Hypertension, atrial fibrillation and age are important contributors to the development of HFPEF and, therefore, its prevalence is likely to increase in the next few decades. The pathophysiology of HFPEF is heterogeneous but with a final common pathway leading to congestion. HF remains a clinical diagnosis but the plasma concentration of B-type natriuretic peptide (eg BNP/N-terminal prohormone BNP (NT-proBNP)), a marker of congestion, is an essential component. Imaging, usually by echocardiography, is required to determine the cardiac phenotype (ie valve disease, left ventricular ejection fraction) underlying HF. A superficially normal echocardiogram does not exclude a diagnosis of HF. No treatment has been shown conclusively to alter the prognosis of HFPEF. However, treatments directed at congestion and hypertension, such as diuretics, mineralocorticoid receptor antagonists (MRAs) and angiotensin converting-enzyme inhibitors, may improve symptoms and probably do improve outcomes. No treatment has yet been shown to reverse the underlying myocardial pathology of HFPEF, although there is some hope that MRAs might. |
11,206 | Intravenous amiodarone homogeneously prolongs ventricular repolarization in patients with life-threatening ventricular tachyarrhythmia. | The most critical adverse effects of class III drugs are marked QT prolongation and torsade de pointes. Even though intravenous amiodarone (iv-Amio) is a representative class III drug, it peculiarly inhibits both clinical ventricular tachycardia/fibrillation (VT/VF) and proarrhythmic effects. To test the hypothesis that iv-Amio homogeneously prolongs repolarization, we evaluated electrocardiographic changes before and during short-term amiodarone therapy, focusing closely on the ventricular dispersion of repolarization.</AbstractText>Twenty-seven consecutive patients treated with iv-Amio for VT/VF as a first-line antiarrhythmic therapy were enrolled in this study. Twelve-lead electrocardiography was recorded before and during amiodarone therapy to evaluate the following electrocardiographic intervals: R-R, QRS, QT, QRS to T-peak (QTp), and T-peak to T-end (Tp-e; as an index of dispersion of repolarization). Repolarization indices were corrected to the heart rate by Bazett's method (QTc, c-QTp, c-Tp-e).</AbstractText>Amiodarone suppressed VT/VF in 19/27 (70%) patients without conferring any proarrhythmic effect. The QTc, c-QTp, and R-R interval were significantly prolonged during amiodarone (476±45ms vs 511±45ms, p<0.05; 338±40ms vs 364±35ms, p<0.05; 762±272ms vs 870±189ms, p<0.05; respectively), whereas the c-Tp-e and QRS durations did not change significantly (139±33ms vs 145±41ms, p=0.25; 96±20ms vs 97±21ms, p=0.33; respectively).</AbstractText>Iv-Amio homogeneously prolongs repolarization and properly inhibits original VT/VF recurrence without inducing torsade de pointes.</AbstractText>Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
11,207 | The effects of α- and β-adrenergic blocking agents on postresuscitation myocardial dysfunction and myocardial tissue injury in a rat model of cardiac arrest. | We investigated the relationship between the severity of postresuscitation (PR) myocardial tissue injury and myocardial dysfunction after the administration of epinephrine as well as the protective effects of α- and β-adrenergic blocking agents. Forty male Sprague-Dawley rats were randomized into 6 groups: (1) placebo; (2) epinephrine; (3) epinephrine pretreated with α1-blocker (prazosin); (4) epinephrine pretreated with α2-blocker (yohimbine); (5) epinephrine pretreated with β-blocker (propranolol); and (6) epinephrine pretreated with β- plus α1-blocker (propranolol and prazosin). Cardiopulmonary resuscitation was initiated after 8 minutes of untreated ventricular fibrillation and continued for an additional 8 minutes. The myocardial function and the serum concentrations of troponin I (Tn I) and N-terminal probrain natriuretic peptide (NT-proBNP) were measured at baseline and after resuscitation. After resuscitation, both Tn I and NT-proBNP were significantly increased in all groups, especially in the epinephrine and epinephrine pretreated with α2-blocker groups. Significantly better PR myocardial function and neurologic deficit score were observed in epinephrine pretreated with the α1- or β-blocker with decreased releases of Tn I and NT-proBNP. However, the most significant improvements were observed in the animals pretreated with β- plus α1-blocker. The present study demonstrated that myocardial stunning may not be the only mechanism of PR myocardial dysfunction. Administration of epinephrine increased the severity of PR myocardial tissue injury and dysfunction. The β- and β- plus α1-blocker pretreatment significantly reduced the severity of PR myocardial tissue injury and myocardial dysfunction with better neurologic function and prolonged duration of survival. |
11,208 | Amplitude spectrum area to guide defibrillation: a validation on 1617 patients with ventricular fibrillation. | This study sought to validate the ability of amplitude spectrum area (AMSA) to predict defibrillation success and long-term survival in a large population of out-of-hospital cardiac arrests.</AbstractText>ECGs recorded by automated external defibrillators from different manufacturers were obtained from patients with cardiac arrests occurring in 8 city areas. A database, including 2447 defibrillations from 1050 patients, was used as the derivation group, and an additional database, including 1381 defibrillations from 567 patients, served as validation. A 2-second ECG window before defibrillation was analyzed, and AMSA was calculated. Univariable and multivariable regression analyses and area under the receiver operating characteristic curve were used for associations between AMSA and study end points: defibrillation success, sustained return of spontaneous circulation, and long-term survival. Among the 2447 defibrillations of the derivation database, 26.2% were successful. AMSA was significantly higher before a successful defibrillation than a failing one (13 ± 5 versus 6.8 ± 3.5 mV-Hz) and was an independent predictor of defibrillation success (odds ratio, 1.33; 95% confidence interval, 1.20-1.37) and sustained return of spontaneous circulation (odds ratio, 1.22; 95% confidence interval, 1.17-1.26). Area under the receiver operating characteristic curve for defibrillation success prediction was 0.86 (95% confidence interval, 0.85-0.88). AMSA was also significantly associated with long-term survival. The following AMSA thresholds were identified: 15.5 mV-Hz for defibrillation success and 6.5 mV-Hz for defibrillation failure. In the validation database, AMSA ≥ 15.5 mV-Hz had a positive predictive value of 84%, whereas AMSA ≤ 6.5 mV-Hz had a negative predictive value of 98%.</AbstractText>In this large derivation-validation study, AMSA was validated as an accurate predictor of defibrillation success. AMSA also appeared as a predictor of long-term survival.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,209 | Arrhythmia burden in elderly patients with severe aortic stenosis as determined by continuous electrocardiographic recording: toward a better understanding of arrhythmic events after transcatheter aortic valve replacement. | This study sought to evaluate the prevalence of previously undiagnosed arrhythmias in candidates for transcatheter aortic valve replacement (TAVR) and to determine the impact on therapy changes and arrhythmic events after the procedure.</AbstractText>A total of 435 candidates for TAVR underwent 24-hour continuous ECG monitoring the day before the procedure. Newly diagnosed arrhythmias were observed in 70 patients (16.1%) before TAVR: paroxysmal atrial fibrillation (AF)/atrial tachycardia (AT) in 28, advanced atrioventricular block or severe bradycardia in 24, nonsustained ventricular tachycardia in 26, and intermittent left bundle-branch block in 3 patients. All arrhythmic events but one were asymptomatic and led to a therapy change in 43% of patients. In patients without known AF/AT, the occurrence of AF/AT during 24-hour ECG recording was associated with a higher rate of 30-day cerebrovascular events (7.1% versus 0.4%; P=0.030). Among the 53 patients with new-onset AF/AT after TAVR, 30.2% had newly diagnosed paroxysmal AF/AT before the procedure. In patients who needed permanent pacemaker implantation after the procedure (n=35), 31.4% had newly diagnosed advanced atrioventricular block or severe bradycardia before TAVR. New-onset persistent left bundle-branch block after TAVR occurred in 37 patients, 8.1% of whom had intermittent left bundle-branch block before the procedure.</AbstractText>Newly diagnosed arrhythmias were observed in approximately a fifth of TAVR candidates, led to a higher rate of cerebrovascular events, and accounted for a third of arrhythmic events after the procedure. This high arrhythmia burden highlights the importance of an early diagnosis of arrhythmic events in such patients to implement the appropriate therapeutic measures earlier.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,210 | Effect of radiofrequency catheter ablation of persistent atrial fibrillation on the left atrial function: assessment by 320-row multislice computed tomography. | Atrial fibrillation (AF) increases the left atrial (LA) volume and deteriorates LA function. Whether successful radiofrequency catheter ablation (RFCA) of persistent AF can reverse this process has not been yet established.</AbstractText>Patients with persistent AF undergoing RFCA were evaluated with pre- and post- (at 6-months of follow-up) procedural multislice computed tomography (MSCT). The LA functions were assessed through LA time-volume curves.</AbstractText>The study population consisted of 44 patients [age 64 (interquartile ranges: 58, 70) years old, 93% male]. Among those, 31 patients (70%) maintained sinus rhythm during the follow-up (no recurrence group; NR group). The remaining 13 patients were classified as the recurrence group (R group). A significant decrease in the minimal and maximal LA volumes was observed in both groups, although this was less pronounced in the R group. Only the NR group had an improvement in the LA expansion index [18% (13, 25) vs. 37% (23, 43), p<0.001], ejection fraction [15% (11, 20) vs. 27% (19, 30), p<0.001] and conduit function [17 ml/m(2) (13, 20) vs. 25 ml/m(2) (20, 34), p<0.001]. An improvement of LV function was also observed only in the NR group.</AbstractText>LA anatomical and functional reverse remodeling after RFCA of persistent AF was demonstrated by MSCT during follow-up, which was more pronounced in patients without AF recurrence.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,211 | A prospective study on safety of catheter ablation procedures: contact force guided ablation could reduce the risk of cardiac perforation. | Contact force (CF) sensing catheters provide advantages with regard to safety and efficacy. This study aimed to evaluate if CF catheters reduce cardiac perforations and other major complications and offer equal safety compared to the magnetic navigation system (MNS).</AbstractText>Data from 1.517 ablation procedures from our prospective registry was analyzed. Ablations were performed using either CF guided catheters (CF group, n=248), non-CF catheters (NCF group, n=813), or MNS (n=456). Four subgroups were analyzed: atrial fibrillation (AF, n=557), supraventricular tachycardia (SVT, n=715), ventricular tachycardia (VT, n=190) and patients with congenital heart defects (CHD, n=55). The primary endpoint of this study was incidence of cardiac perforation. Secondary endpoints were major and minor complications within 30 days of the procedure.</AbstractText>Complications occurred in 11.3% (n=172) of the procedures. In 2.8% (n=43) a major complication occurred, 0.9% (n=13) had a perforation, 8.5% (n=129) had a minor complication and 2 patients died (0.1%). No cardiac perforation occurred in the CF group, which was significantly different from NCF procedures (0.0% vs. 1.6%; relative risk 0.76, 95% CI 0.74-0.79, P=0.031) and equal to MNS (0.0%). This was also observed in the AF subgroup (0.0% vs. 3.3%; RR 0.67, 95% CI 0.63-0.72, P=0.021), and the occurrence of major complications was lower for CF versus NCF procedures (2.1% vs. 7.8%, P=0.010).</AbstractText>CF-guided catheter ablation is superior to NCF with regard to procedural safety and avoidance of cardiac perforation. This difference is due to a reduction of cardiac perforation and major complications in the AF subgroup.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,212 | Adverse structural remodeling of the left ventricle and ventricular arrhythmias in patients with depressed ejection fraction. | The relationship of life-threatening ventricular arrhythmias to specific patterns of adverse LV remodeling has not been reported. We examined the relationship of ventricular tachycardia and/or fibrillation (VT/VF) to the pattern of left ventricular (LV) structural remodeling and to the degree of LV dysfunction in patients with a low ejection fraction (EF).</AbstractText>Data from 127 patients with a low EF (≤0.45) and an implantable cardioverter-defibrillator (ICD) were examined and VT/VF identified by means of ICD device interrogation. Echocardiographic data were used to define LV structural remodeling (eccentric hypertrophy, concentric remodeling/hypertrophy, and normal geometry). VT/VF occurred in 26% of the 127 patients. VT/VF was more common in the 60 patients with LV hypertrophy versus the 67 with normal LV mass (40% vs 13%; P = .001) and in the 61 patients with LV enlargement versus the 66 with a normal chamber size (34% vs 18%; P = .04). When LV chamber size, wall mass, and geometry were assessed in a combinatorial fashion, a Kaplan-Meier analysis indicated that the occurrence of VT/VF was highest in the patients with eccentric hypertrophy (43%), intermediate in those with concentric remodeling/hypertrophy (30%), and lowest (12%) in those with normal geometry (all P < .02). The EFs were similar (P = ns) in these 3 groups of distinctly different patterns of remodeling.</AbstractText>Life-threatening ventricular arrhythmias in patients with a low EF are related to the pattern of LV remodeling, not the degree of LV dysfunction. Risk stratification of such patients might be improved by a consideration of the pattern of LV remodeling.</AbstractText>Copyright © 2015 Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,213 | Minimizing pre-shock chest compression pauses in a cardiopulmonary resuscitation cycle by performing an earlier rhythm analysis. | Guidelines recommend 2min of CPR after defibrillation attempts followed by ECG analysis during chest compression pause. This pause may reduce the likelihood of return of spontaneous circulation (ROSC) and survival. We have evaluated the possibility of analysing the rhythm earlier in the CPR cycle in an attempt to replace immediate pre-shock rhythm analysis.</AbstractText>The randomized Circulation Improving Resuscitation Care (CIRC) trial included patients with out of hospital cardiac arrest of presumed cardiac aetiology. Defibrillator data were used to categorize ECG rhythms as shockable or non-shockable 1min post-shock and immediately before next shock. ROSC was determined from end-tidal CO2, transthoracic impedance (TTI), and patient records. TTI was used to identify chest compressions. Artefact free ECGs were categorized during periods without chest compressions. Episodes without ECG or TTI data or with undeterminable ECG rhythm were excluded. Data were analyzed using descriptive statistics. Of 1657 patients who received 3409 analysable shocks, the rhythm was shockable in 1529 (44.9%) cases 1min post-shock, 13 (0.9%) of which were no longer shockable immediately prior to next possible shock. Of these, three had converted to asystole, seven to PEA and three to ROSC.</AbstractText>While a shockable rhythm 1min post-shock was present also immediately before next possible defibrillation attempt in most cases, three patients had ROSC. Studies are needed to document if moving the pre-shock rhythm analysis will increase shocks delivered to organized rhythms, and if it will increase shock success and survival.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,214 | P-wave duration changes and dispersion in preeclampsia. | The purpose of this research was to study P wave parameters to determine the association between preeclampsia and future cardiovascular risk and to study the possible correlation between P waves and severity of preeclampsia.</AbstractText>In this case-control study 58 pregnant women with preeclampsia and 30 normal pregnant women were compared by measuring maximum and minimum P-wave durations and P-wave dispersion (Pd) in the late third trimester.</AbstractText>Minimum P wave values were lower and Pd values were higher, both significantly, in the preeclampsia groups than in the control group. In addition, the Pd values of the severe preeclampsia group were higher compared to that of the mild preeclampsia group.</AbstractText>Preeclampsia predisposes the patient to future cardiovascular complications including atrial or ventricular arrhythmias, but validated tools to assess the risks are yet not available. P-wave duration and Pd constitute a recent contribution to the field of noninvasive electrocardiology. Our data clearly demonstrated that minimum P wave and Pd values were significantly altered in preeclamptic pregnant women when compared to the controls. This important association can be used to screen women for increased risk in order to better target counseling regardinglifestyle modifications and to follow up and manage women with a history of preeclampsia more closely.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,215 | Tachycardia-dependent augmentation of "notched J waves" in a general patient population without ventricular fibrillation or cardiac arrest: not a repolarization but a depolarization abnormality? | J waves can be observed in individuals of the general population, but electrocardiographic characteristics are poorly understood.</AbstractText>The purpose of this study was to examine the J-wave dynamicity in a general patient population.</AbstractText>The responses of J waves (>0.1 mV above the isoelectric line in 2 contiguous leads) to varying RR intervals were analyzed. Patients with aborted sudden cardiac death, documented ventricular fibrillation, or a family history of sudden cardiac death were excluded. The J-wave amplitude was measured at baseline, in beats with short RR intervals in conducted atrial premature beats (APBs) or atrial stimulation during the electrophysiology study, and in the beats next to APBs with prolonged RR intervals.</AbstractText>Mainly notched J waves were identified in 94 of 701 (24.5%) general patients (13.4%), and APBs were present in 23 of 94 (24.5%) patients. The mean baseline amplitude of J waves was 0.20 ± 0.06 mV at the baseline RR interval of 853 ± 152 ms, 0.25 ± 0.11 mV at the RR interval in the conducted APB of 545 ± 133 ms (P = .0018), and 0.19 ± 0.08 mV at the RR interval of 1146 ± 314 ms (P = .3102). The clinical characteristics were not different between patients with and without tachycardia-dependent augmentation of J waves. Augmentation of J waves was confirmed by the electrophysiology study: 0.28 ± 0.12 mV vs 0.42 ± 0.11 mV at baseline and in the beats of atrial stimulation, respectively (P = .0001). However, no bradycardia-dependent augmentation (>0.05 mV) was observed. Such tachycardia-dependent augmentation can represent depolarization abnormality rather than repolarization abnormality.</AbstractText>J waves in a general patient population were augmented at shorter RR intervals, but not at prolonged RR intervals. Mechanistically, conduction delay is most likely responsible for this.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,216 | Subcutaneous nerve activity and spontaneous ventricular arrhythmias in ambulatory dogs. | Stellate ganglion nerve activity (SGNA) is important in ventricular arrhythmogenesis. However, because thoracotomy is needed to access the stellate ganglion, it is difficult to use SGNA for risk stratification.</AbstractText>The purpose of this study was to test the hypothesis that subcutaneous nerve activity (SCNA) in canines can be used to estimate SGNA and predict ventricular arrhythmia.</AbstractText>We implanted radiotransmitters to continuously monitor left stellate ganglion and subcutaneous electrical activities in 7 ambulatory dogs with myocardial infarction, complete heart block, and nerve growth factor infusion to the left stellate ganglion.</AbstractText>Spontaneous ventricular tachycardia (VT) or ventricular fibrillation (VF) was documented in each dog. SCNA preceded a combined 61 episodes of VT and VF, 61 frequent bigeminy or couplets, and 61 premature ventricular contractions within 15 seconds in 70%, 59%, and 61% of arrhythmias, respectively. Similar incidence of 75%, 69%, and 62% was noted for SGNA. Progressive increase in SCNA [48.9 (95% confidence interval [CI] 39.3-58.5) vs 61.8 (95% CI 45.9-77.6) vs 75.1 (95% CI 57.5-92.7) mV-s] and SGNA [48.6 (95% CI 40.9-56.3) vs 58.5 (95% CI 47.5-69.4) vs 69.0 (95% CI 53.8-84.2) mV-s] integrated over 20-second intervals was demonstrated 60 seconds, 40 seconds, and 20 seconds before VT/VF (P <.05), respectively. The Pearson correlation coefficient for integrated SCNA and SGNA was 0.73 ± 0.18 (P <.0001 for all dogs, n = 5). Both SCNA and SGNA exhibited circadian variation.</AbstractText>SCNA can be used as an estimate of SGNA to predict susceptibility to VT and VF in a canine model of ventricular arrhythmia and sudden cardiac death.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,217 | Feedback to providers improves evidence-based implantable cardioverter-defibrillator programming and reduces shocks. | Implantable cardioverter-defibrillator (ICD) shocks are associated with increased anxiety, health care utilization, and potentially mortality.</AbstractText>The purpose of the Shock-Less Study was to determine if providing feedback reports to physicians on their adherence to evidence-based shock reduction programming could improve their programming behavior and reduce shocks.</AbstractText>Shock-Less enrolled primary prevention (PP) and secondary prevention (SP) ICD patients between 2009 and 2012 at 118 study centers worldwide and followed patients longitudinally after their ICD implant. Center-specific therapy programming reports (TPRs) were delivered to each center 9 to 12 months after their first enrollment. The reports detailed adherence to evidence-based programming targets: number of intervals to detect ventricular fibrillation (VF NID), longest treatment interval (LTI), supraventricular tachycardia (SVT) discriminators (Wavelet, PR Logic), SVT limit, Lead Integrity Alert (LIA), and antitachycardia pacing (ATP). Clinicians programmed ICDs at their discretion. The primary outcome measure was the change in utilization of evidence-based shock reduction programming before (phase I, n = 2694 patients) and after initiation of the TPR (phase II, n = 1438 patients).</AbstractText>Patients implanted after feedback reports (phase II) were up to 20% more likely to have their ICDs programmed in line with evidence-based shock reduction programming (eg, VF NID in PP patients 30/40 in 33.5% vs 18.6%, P < .0001). Patients implanted in phase II had a lower risk of all-cause shock (adjusted hazard ratio 0.72, 95% confidence interval 0.58-0.90, P = .003).</AbstractText>Providing programming feedback reports improves adherence to evidence-based shock reduction programming and is associated with lower risk of ICD shocks.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,218 | Increased extent of myocardial fibrosis in genotyped hypertrophic cardiomyopathy with ventricular tachyarrhythmias. | Occurrence of malignant ventricular tachyarrhythmias such as ventricular tachycardia and fibrillation (VT/VF) in hypertrophic cardiomyopathy (HCM) can be related to the extent of myocardial fibrosis. Although late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging has been used to detect myocardial fibrosis, few data exist regarding relationships between CMR-determined myocardial fibrosis and VT/VF in genotyped HCM populations.</AbstractText>We retrospectively investigated whether the extent of LGE can be increased in HCM patients with VT/VF compared to those without VT/VF in the genotyped HCM population.</AbstractText>We studied 35 HCM patients harboring sarcomere gene mutations (TNNI3=22, MYBPC3=12, MYH7=1) who underwent both CMR imaging and 24-h ambulatory electrocardiographic monitoring. VT/VF were identified in 6 patients (2 men, mean age 55.0 years). The extent of LGE was significantly increased in patients with VT/VF (n=6) compared with those without VT/VF (n=29) (18.6±14.4% vs. 8.3±11.4%, p=0.04), although the LGE extent was not an independent predictor for the occurrence of VT/VF. Applying a cut-off point ≥3.25%, episodes of VT/VF were identified with a sensitivity of 100%, specificity of 51.7%, positive predictive value of 30%, negative predictive value of 100%, and the area under the curve of 0.767 (95% confidence interval: 0.590-0.944).</AbstractText>These results demonstrate that myocardial fibrosis determined by CMR imaging may be increased in genotyped HCM patients with episodes of VT/VF. A further prospective study will be needed to clarify the association between the LGE extent and arrhythmic events in HCM patients harboring sarcomere gene mutations.</AbstractText>Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
11,219 | Natural history and prognostic factors in alcoholic cardiomyopathy. | This study sought to determine the natural history of contemporary alcoholic cardiomyopathy (ACM), to compare it with that of idiopathic dilated cardiomyopathy (IDCM), and to identify risk factors for poor outcome.</AbstractText>ACM is a common cause of dilated cardiomyopathy (DCM), but little is known about its natural history or the effect of reducing alcohol intake on disease progression.</AbstractText>We studied the clinical characteristics and outcomes of 94 consecutive patients with ACM and 188 with IDCM, evaluated over the period between 1993 and 2011.</AbstractText>After a median follow-up of 59 months (interquartile range: 25 to 107 months), 14 ACM patients (15%) had died from cardiovascular causes (6 from heart failure and 8 from sudden cardiac death), 14 (15%) underwent heart transplantation, 35 (37%) experienced recovery in left ventricular function, and 31 (33%) remained clinically stable without improvement in systolic function. Transplantation-free survival was higher in ACM patients than in IDCM patients (p = 0.002), and ACM was associated with a favorable outcome on multiple analysis of the entire cohort (odds ratio [OR]: 0.4; 95% confidence interval [CI]: 0.2 to 0.8; p = 0.01). Independent predictors of death or heart transplantation in ACM identified by multiple logistic regression analysis were atrial fibrillation (OR: 9.7; 95% CI: 2.56 to 36.79; p = 0.001); QRS duration >120 ms (OR: 7.2; 95% CI: 2.02 to 26; p = 0.002), and lack of beta-blocker therapy (OR: 4.4; 95% CI: 1.35 to 14.49; p = 0.014). ACM patients who reduced their alcohol intake to moderate levels exhibited similar survival (p = 0.22) and cardiac function recovery (p = 0.8) as abstainers.</AbstractText>ACM has a better prognosis than IDCM. Atrial fibrillation, QRS width >120 ms, and the absence of beta-blocker therapy identify patients with a poor outcome. Alcohol abstainers and those who reduce intake to a moderate degree show similar clinical outcomes.</AbstractText>Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,220 | Continuous electroencephalogram patterns are suggestive of eventual neurologic outcomes in post-cardiac arrest patients treated with therapeutic hypothermia. | Therapeutic hypothermia (TH) after cardiac arrest (CA) resuscitation is the first therapy proven to increase survival to discharge and neurologic recovery. Methods for neurologic and mortality prognostication after CA resuscitation have been called into question because they were developed based on evidence that was developed prior to the advent of TH. This study examines the relationship between electroencephalogram (EEG) patterns and mortality and neurologic outcomes in post-CA patients undergoing TH.</AbstractText>Eighty-three of 732 patients who had continuous EEG (cEEG) monitoring during TH were included. Continuous EEG tracings were classified as isoelectric, low voltage, burst suppression, epileptic form, and diffuse slowing. Primary outcomes are survival to discharge and Cerebral Performance Categories (CPCs) at hospital discharge.</AbstractText>Among patients with favorable neurologic outcomes (CPC1 and CPC2), the duration cardiopulmonary resuscitation and time until return of spontaneous circulation were shorter than observed in patients with poorer neurologic outcomes (CPC3, CPC4, and CPC5). The time to target temperature was equivalent among neurologic outcome groups (499.5 minutes vs 431.0 minutes, P = .09). Favorable neurologic outcome was associated with initial presentation with ventricular tachycardia or ventricular fibrillation and had cEEG patterns suggestive of diffuse slowing and epileptiform waves.</AbstractText>The use of cEEG can provide prognostication information otherwise not obtainable by clinical examination. Specific cEEG patterns predicted probability of mortality for patients according to their initial rhythm of CA as a function of cardiopulmonary resuscitation time.</AbstractText>Copyright © 2014 Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,221 | Profound symptomatic bradycardia requiring transvenous pacing after a single dose of tizanidine. | We report a case of profound symptomatic bradycardia after a single dose of tizanidine.</AbstractText>A 93-year-old female became altered and was found to have hypotension and profound symptomatic bradycardia 30 min post ingestion of a single 4-mg dose of tizanidine at her physician's office. Emergency Medical Services was called to scene and patient was transported to our tertiary medical center. In the emergency department, the patient required intubation, vasopressor support, and transcutaneous pacing. An electrocardiogram revealed atrial fibrillation with slow ventricular response with a heart rate of 19 beats/min. The patient was transferred to the intensive care unit and subsequently taken for cardiac catheterization, where a transvenous pacer was placed. During the next few days, her vital signs and mental status improved, allowing for successful extubation. Before discharge, the patient received a single-chamber pacemaker.</AbstractText>Profound symptomatic bradycardia from a single dose of tizanidine has not been reported. A review of the patient's medications did not reveal a significant cytochrome P450 drug interaction to result in an adverse effect as previously reported in the literature.</AbstractText>Tizanidine should be used cautiously in elderly population and drug interactions screening should be performed.</AbstractText>Copyright © 2015 Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,222 | Catheter ablation of atrial fibrillation in patients with concomitant left ventricular impairment: a systematic review of efficacy and effect on ejection fraction. | Catheter ablation of atrial fibrillation (AF) is an established rhythm control strategy; however, the impact of co-existing LV systolic dysfunction (LVSD) on ablation success is less well understood. This systematic review compiles the outcomes of catheter ablation of atrial fibrillation in patients with LVSD.</AbstractText>An electronic database (Pubmed, Scopus, Embase) search using the keywords 'atrial fibrillation AND ablation AND (ventricular dysfunction OR heart failure OR cardiomyopathy)' was performed for English scientific literature up to 01/01/2014. 2484 references were retrieved and evaluated for relevance by three reviewers. Reviews and reference lists of retrieved articles were also examined to ensure all relevant studies were included. Data was extracted from 19 studies, including a total of 914 patients.</AbstractText>Single-procedure success in LVSD patients for AF ablation was 56.5% (95% CI: 48%-64%). Overall multiple-procedure (including the use of anti-arrhythmic drugs) in LVSD patients for AF ablation was 81.8% (95% CI: 75%-87%). The mean increase in LVEF following AF ablation was 13.3% (95% CI: 10.8%-15.9%). Seven studies reported improvements in exercise capacity and quality of life information using standardised criteria. The pooled rate of serious adverse events was 5.5% (95% CI: 3.7%-8.1%).</AbstractText>Catheter ablation may be an effective therapy in AF patients with left ventricular systolic impairment, and can be associated with improvements in left ventricular function, quality of life, exercise capacity, and modest rates of serious adverse events.</AbstractText>Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
11,223 | Impact of left ventricular diastolic dysfunction on outcome of catheter ablation for atrial fibrillation in patients with hypertrophic cardiomyopathy. | The relationship between outcome of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) and the severity of left ventricular (LV) diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM) remains unknown.</AbstractText>Twenty-two HCM patients (12 female, aged 65 ± 11 years) with paroxysmal (n=5; 23%) or persistent (n=17; 77%) AF were enrolled. LV diastolic function was evaluated according to the ratio of the mitral inflow early filling velocity to the velocity of the early medial mitral annular ascent (E/e') measured on pulsed wave and tissue Doppler assessments in all patients. Pulmonary vein isolation was performed in all patients. A second procedure was performed in 3 patients. During a follow-up of 21 ± 12 months, sinus rhythm was maintained in 13 of 22 patients (59%). E/e' was significantly higher in the patients with AF recurrence than in those without (18 ± 7 vs. 11 ± 3; P<0.01). On Kaplan-Meier analysis the prevalence of AF recurrence was significantly higher in patients with E/e' ≥ 15 (n=6) than in those with E/e' <15 (n=16; P<0.01). On multivariate Cox regression analysis the only significant and independent predictor for AF recurrence was E/e' (hazard ratio, 1.16; 95% confidence interval: 1.01-1.37, P=0.03).</AbstractText>LV diastolic dysfunction evaluated using E/e' was associated with difficulty of rhythm control after RFCA in patients with HCM and AF.</AbstractText> |
11,224 | [ST segment elevation myocardial infarction in a young patient: special physiopathology and unusual management]. | We report the case of a 24-year-old patient admitted for anterior ST segment elevation myocardial complicated by ventricular fibrillation and revealing thrombotic sub occlusion of the left anterior descending coronary artery. Revascularization is achieved by manual thrombectomy and use of Glycoprotein GPIIbIIIa inhibitors and permits to restore TIMI 3 flow. Given the large thrombotic burden, the patient is initially treated medically (optimal anti thrombotic therapy without stenting) and benefits from angiographic control 48 hours later with imaging by Optical Coherence Tomography (OCT). It shows a reduction of thrombus burden and lack of significant underlying organic lesion (no organic stenosis or plaque rupture). In view of these data, it was decided to continue medical treatment alone without stenting. OCT imaging at 6 months shows atheroma without stenosis, thrombus or plaque rupture. This young patient remains asymptomatic and recovered normal left ventricular function with a 2-year follow-up. |
11,225 | Characterization of an anesthetized dog model of transient cardiac ischemia and rapid pacing: a pilot study for preclinical assessment of the potential for proarrhythmic risk of novel drug candidates. | Preclinical proarrhythmic risk assessment of drug candidates is focused predominantly on arrhythmias arising from repolarization abnormalities. However, drug-induced cardiac conduction slowing is associated with significant risk of life-threatening ventricular arrhythmias, particularly in a setting of cardiac ischemia. Therefore, we optimized and characterized an anesthetized dog model to evaluate the potential proarrhythmic risk of drug candidates in ischemic heart disease patients.</AbstractText>Anesthetized dogs were instrumented with atrial and ventricular epicardial electrodes for pacing and measurement of conduction times, and a balloon occluder and flow probe placed around the left anterior descending coronary artery (LAD) distal to the first branch. Conduction times, ECG intervals and incidence of arrhythmias were assessed serially at the end of each dose infusion (flecainide: 0.32, 0.63, 1.25, 2.5 and 5mg/kg, i.v.; dofetilide:1.25, 2.5, 5, 10 and 20 μg/kg, i.v.; or vehicle; n=6/group) both during normal flow (with and without rapid pacing) and during 5-min LAD occlusion (with and without rapid pacing). Compound X, a development candidate with mild conduction slowing activity, was also evaluated.</AbstractText>Flecainide produced pronounced, dose-dependent slowing of conduction that was exacerbated during ischemia and rapid pacing. In addition, ventricular tachycardia (VT) and fibrillation (VF) occurred in 4 of 6 dogs (3 VF @ 0.63 mg/kg; 1VT @ 2.5mg/kg). In contrast, no animals in the vehicle group developed arrhythmias. Dofetilide, a potent IKr blocker that does not slow conduction, prolonged QT interval but did not cause further conduction slowing during ischemia with or without pacing and there were no arrhythmias. Compound X, like flecainide, produced marked conduction slowing and arrhythmias (VT, VF) during ischemia and pacing.</AbstractText>This model may be useful to more accurately define shifts in safety margins in a setting of ischemia and increased cardiac demand for drugs that slow conduction.</AbstractText>Copyright © 2014 Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,226 | Cardiopulmonary resuscitation duty cycle in out-of-hospital cardiac arrest. | Duty cycle is the portion of time spent in compression relative to total time of the compression-decompression cycle. Guidelines recommend a 50% duty cycle based largely on animal investigation. We undertook a descriptive evaluation of duty cycle in human resuscitation, and whether duty cycle correlates with other CPR measures.</AbstractText>We calculated the duty cycle, compression depth, and compression rate during EMS resuscitation of 164 patients with out-of-hospital ventricular fibrillation cardiac arrest. We captured force recordings from a chest accelerometer to measure ten-second CPR epochs that preceded rhythm analysis. Duty cycle was calculated using two methods. Effective compression time (ECT) is the time from beginning to end of compression divided by total period for that compression-decompression cycle. Area duty cycle (ADC) is the ratio of area under the force curve divided by total area of one compression-decompression cycle. We evaluated the compression depth and compression rate according to duty cycle quartiles.</AbstractText>There were 369 ten-second epochs among 164 patients. The median duty cycle was 38.8% (SD=5.5%) using ECT and 32.2% (SD=4.3%) using ADC. A relatively shorter compression phase (lower duty cycle) was associated with greater compression depth (test for trend <0.05 for ECT and ADC) and slower compression rate (test for trend <0.05 for ADC). Sixty-one of 164 patients (37%) survived to hospital discharge.</AbstractText>Duty cycle was below the 50% recommended guideline, and was associated with compression depth and rate. These findings provider rationale to incorporate duty cycle into research aimed at understanding optimal CPR metrics.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,227 | Effects of the administration of 2,3-butanedione monoxime during conventional cardiopulmonary resuscitation on ischaemic contracture and resuscitability in a pig model of out-of-hospital cardiac arrest. | Ischaemic contracture compromises the haemodynamic effectiveness of cardiopulmonary resuscitation and resuscitability. 2,3-Butanedione monoxime (BDM) reduced ischaemic contracture by inhibiting actin-myosin crossbridge formation in an isolated heart model. We investigated the effects of BDM on ischaemic contracture and resuscitation outcomes in a pig model of out-of-hospital cardiac arrest (OHCA).</AbstractText>After 15min of untreated ventricular fibrillation, followed by 8min of basic life support, 16 pigs were randomised to receive either 2mlkg(-1) of BDM solution (25gl(-1)) or 2mlkg(-1) of saline during advanced cardiac life support (ACLS).</AbstractText>During the ACLS, the control group showed an increase in left ventricular (LV) wall thickness from 10.0mm (10.0-10.8) to 13.0mm (13.0-13.0) and a decrease in LV chamber area from 8.13cm(2) (7.59-9.29) to 7.47cm(2) (5.84-8.43). In contrast, the BDM group showed a decrease in the LV wall thickness from 10mm (9.0-10.8) to 8.5mm (7.0-9.8) and an increase in the LV chamber area from 9.86cm(2) (7.22-12.39) to 12.15 cm(2) (8.02-14.40). Mixed model analyses of the LV wall thickness and LV chamber area revealed significant group effects and group-time interactions. Spontaneous circulation was restored in four (50%) animals in the control group and in eight (100%) animals in the BDM group (p=0.077). All the resuscitated animals survived during an intensive care period of 4h.</AbstractText>BDM administered during cardiopulmonary resuscitation reversed ischaemic contracture in a pig model of OHCA.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,228 | Influence of renal impairment on myocardial function in outpatients with systolic heart failure: an echocardiographic and cardiac biomarker study. | Renal dysfunction (RD) is associated with poor outcome in systolic heart failure (HF). Left ventricular ejection fraction (LVEF) is not depressed to a greater extent in patients with RD compared to patients with normal renal function, but it is relatively unknown whether other measures of myocardial function are impaired by RD. The objective of the present study is to evaluate whether RD in systolic HF is associated with excessive impairment of myocardial function, evaluated by strain analysis and cardiac biomarkers.</AbstractText>Patients with LVEF <0.45% were enrolled from an outpatient HF clinic. The patients underwent advanced echocardiography. Glomerular filtration rate was estimated by the CKD-EPI equation (eGFR) and patients grouped by eGFR: eGFR group-I, ≥ 90 ml/min/1.73 m(2); eGFR group-II, 60-89 ml/min/1.73 m(2); and eGFR group-III, ≤ 59 ml/min/1.73 m(2). Multivariate regression models were developed to evaluate the associations between eGFR groups, echocardiographic measures and cardiac biomarkers.</AbstractText>A total of 149 patients participated in the study. Median age was 69 years, 26% were female; LVEF was 33%. Patients with a low eGFR were older (P < 0.001), but there were no differences in frequency of atrial fibrillation, hypertension, diabetes and ischemic heart disease between eGFR groups (P > 0.05 for all). RD was associated with impaired global longitudinal strain (P = 0.018), increased E/e' (P = 0.032), larger left atria (P = 0.038) and increased levels of proANP (P < 0.001), NT-proBNP (P < 0.001) and troponin I (P = 0.019) after adjustment for traditional confounders.</AbstractText>Echocardiographic measures and biomarkers reflecting different aspects of myocardial function are impaired in systolic HF patients with RD and the increased mortality risk in these patients may partly be explained by a depressed cardiac function.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,229 | Characteristics of ventricular fibrillation in relation to cardiac aetiology and shock success: A waveform analysis study in ICD-patients. | Ventricular fibrillation (VF) waveform characteristics are associated with cardiac arrest duration and defibrillation success. Recent animal studies found that VF characteristics and shock success also depend on the presence of myocardial infarction (MI). In patients, VF induction after implantable cardioverter defibrillator (ICD) implantation offers a unique setting to study early VF characteristics: we studied the relation with cardiac disease--either presence or absence of a previous MI--and with shock success.</AbstractText>Retrospective cohort study of ICD-patients who underwent defibrillation testing, 117 (63%) with and 69 (37%) without a previous MI. Intracardiac recordings of induced VF were analysed using Fourier analysis.</AbstractText>In previous MI-patients, the fundamental frequency and organisation index of the VF signal were significantly lower as compared with patients without a previous MI: 4.9 Hz ± 0.6 vs. 5.2 Hz ± 0.6 (p = 0.005) and 56% ± 10 vs. 60% ± 9 (p = 0.001), respectively. The median frequency was not different (p = 0.25). We found no association between VF characteristics and ICD shock success.</AbstractText>In analogy with observations in animals, we found that a history of a previous MI was associated with slower and less organised VF. In our cohort of ICD-patients, early VF waveform characteristics were not associated with shock outcomes. Further study is warranted to determine to what extent VF characteristics are influenced by the underlying aetiology on the one hand, and time delay on the other. These findings could improve insight into the potential value of VF analysis to guide shock delivery.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,230 | A tourniquet assisted cardiopulmonary resuscitation augments myocardial perfusion in a porcine model of cardiac arrest. | During cardiopulmonary resuscitation (CPR), myocardial blood flow generated by chest compression rarely exceeds 35% of its normal level. Cardiac output generated by chest compression decreases gradually with the prolongation of cardiac arrest and resuscitation. Early studies have demonstrated that myocardial blood flow during CPR is largely dependent on peripheral vascular resistance. In this study, we investigated the effects of chest compression in combination with physical control of peripheral vascular resistance assisted by tourniquets on myocardial blood flow during CPR.</AbstractText>Ventricular fibrillation was induced and untreated for 7 min in ten male domestic pigs weighing between 33 and 37 kg. The animals were then randomized to receive CPR alone or a tourniquet assisted CPR (T-CPR). In the CPR alone group, chest compression was performed by a miniaturized mechanical chest compressor. In the T-CPR group, coincident with the start of resuscitation, the thin elastic tourniquets were wrapped around the four limbs from the distal end to the proximal part. After 2 min of CPR, epinephrine (20 μg/kg) was administered via the femoral vein. After 5 min of CPR, defibrillation was attempted by a single 150 J shock. If resuscitation was not successful, CPR was resumed for 2 min before the next defibrillation. The protocol was continued until successful resuscitation or for a total of 15 min. Five minutes after resuscitation, the elastic tourniquets were removed. The resuscitated animals were observed for 2h.</AbstractText>T-CPR generated significantly greater coronary perfusion pressure, end-tidal carbon dioxide and carotid blood flow. There was no difference in both intrathoracic positive and negative pressures between the two groups. All animals were successfully resuscitated with a single shock in both groups. There were no significant changes in hemodynamics observed in the animals treated in the T-CPR group before-and-after the release of tourniquets at post-resuscitation 5 min.</AbstractText>T-CPR improves myocardial and cerebral perfusion during CPR. It may provide a new and convenient method for augmenting myocardial and cerebral blood flow during CPR.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,231 | Recurrent ventricular fibrillation: experience with first responders prior to advanced life support interventions. | Following defibrillation, ventricular fibrillation (VF) frequently recurs during out-of-hospital cardiac arrest (OHCA). Prior studies have reported conflicting results regarding its association with survival. The aim of this study was to examine the impact of recurrent VF in the presence of first responders before advanced life support (ALS) interventions.</AbstractText>Electrocardiographic data from first responder automated external defibrillators (AEDs) were analyzed. A successful shock was defined as termination of VF for 5s or longer. Recurrent VF was defined as any VF that occurred after a successful shock. The primary outcome was neurologically intact survival to hospital discharge (CPC 1-2).</AbstractText>108 patients within our emergency system experienced a witnessed VF arrest. Of these, 73 (68%) had at least one recurrence of VF. Median time to recurrence of VF was 25s [interquartile range (IQR) 11-66s]. Median time in recurrent VF was 180s (IQR 105-266s). Survival was observed in 25 (71%) of patients with no recurrent VF and in 36 (49%) who had recurrence. Recurrent VF was associated with a lower odds of survival on univariate analysis (OR 0.39, 95% CI 0.16-0.92, p=0.0325). After adjusting for bystander CPR, gender and age, recurrent VF had a similar direction of effect but was no longer significantly associated with neurologically intact survival (OR 0.44, 95% CI 0.17-1.11, p=0.081).</AbstractText>In the presence of first responders, VF recurred in 68% of patients. Recurrent VF was associated with a lower odds of survival, though its prognostic significance appeared to be blunted when considered in light of confounding variables. Recurrent VF may have significant survival implications, and further studies to assess its prognostic significance should be performed.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,232 | Tilting for perfusion: head-up position during cardiopulmonary resuscitation improves brain flow in a porcine model of cardiac arrest. | Cerebral perfusion is compromised during cardiopulmonary resuscitation (CPR). We hypothesized that beneficial effects of gravity on the venous circulation during CPR performed in the head-up tilt (HUT) position would improve cerebral perfusion compared with supine or head-down tilt (HDT).</AbstractText>Twenty-two pigs were sedated, intubated, anesthetized, paralyzed and placed on a tilt table. After 6min of untreated ventricular fibrillation (VF) CPR was performed on 14 pigs for 3min with an automated CPR device called LUCAS (L) plus an impedance threshold device (ITD), followed by 5min of L-CPR+ITD at 0° supine, 5min at 30° HUT, and then 5min at 30° HDT. Microspheres were used to measure organ blood flow in 8 pigs. L-CPR+ITD was performed on 8 additional pigs at 0°, 20°, 30°, 40°, and 50° HUT.</AbstractText>Coronary perfusion pressure was 19±2mmHg at 0° vs. 30±3 at 30° HUT (p<0.001) and 10±3 at 30° HDT (p<0.001). Cerebral perfusion pressure was 19±3 at 0° vs. 35±3 at 30° HUT (p<0.001) and 4±4 at 30° HDT (p<0.001). Brain-blood flow was 0.19±0.04mlmin(-1)g(-1) at 0° vs. 0.27±0.04 at 30° HUT (p=0.01) and 0.14±0.06 at 30° HDT (p=0.16). Heart blood flow was not significantly different between interventions. With 0, 10, 20, 30, 40 and 50° HUT, ICP values were 21±2, 16±2, 10±2, 5±2, 0±2, -5±2 respectively, (p<0.001), CerPP increased linearly (p=0.001), and CPP remained constant.</AbstractText>During CPR, HDT decreased brain flow whereas HUT significantly lowered ICP and improved cerebral perfusion. Further studies are warranted to explore this new resuscitation concept.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,233 | Bundled postconditioning therapies improve hemodynamics and neurologic recovery after 17 min of untreated cardiac arrest. | Ischemic postconditioning (stutter CPR) and sevoflurane have been shown to mitigate the effects of reperfusion injury in cardiac tissue after 15min of ventricular fibrillation (VF) cardiac arrest. Poloxamer 188 (P188) has also proven beneficial to neuronal and cardiac tissue during reperfusion injury in human and animal models. We hypothesized that the use of stutter CPR, sevoflurane, and P188 combined with standard advanced life support would improve post-resuscitation cardiac and neurologic function after prolonged VF arrest.</AbstractText>Following 17min of untreated VF, 20 pigs were randomized to Control treatment with active compression/decompression (ACD) CPR and impedance threshold device (ITD) (n=8) or Bundle therapy with stutter ACD CPR+ITD+sevoflurane+P188 (n=12). Epinephrine and post-resuscitation hypothermia were given in both groups per standard protocol. Animals that achieved return of spontaneous circulation (ROSC) were evaluated with echocardiography, biomarkers, and a blinded neurologic assessment with a cerebral performance category score.</AbstractText>Bundle therapy improved hemodynamics during resuscitation, reduced need for epinephrine and repeated defibrillation, reduced biomarkers of cardiac injury and end-organ dysfunction, and increased left ventricular ejection fraction compared to Controls. Bundle therapy also improved rates of ROSC (100% vs. 50%), freedom from major adverse events (50% vs. 0% at 48h), and neurologic function (42% with mild or no neurologic deficit and 17% achieving normal function at 48h).</AbstractText>Bundle therapy with a combination of stutter ACD CPR, ITD, sevoflurane, and P188 improved cardiac and neurologic function after 17min of untreated cardiac arrest in pigs. All studies were performed with approval from the Institutional Animal Care Committee of the Minneapolis Medical Research Foundation (protocol #12-11).</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,234 | Explaining unexplained dyspnea: the ever "holesome" heart. | A 63-year-old man was evaluated in consultation for unexplained dyspnea. At the time of the initial clinical encounter at our institution, the patient endorsed a 10-year history of progressive exertional dyspnea, which had become debilitating over the preceding 3 months and was characterized by shortness of breath accompanying subtle physical activities such as tying shoelaces. The patient underwent multiple hospital admissions reportedly for the treatment of congestive heart failure ascribed to impaired left ventricular (LV) diastolic function. Review of systems identified postural dizziness and history of near syncope, possible nocturnal dyspnea, and peripheral neuropathy, but not cardiac angina, orthopnea, nocturia, edema, cough, palpitations, syncope, claudication, or other cardiopulmonary symptoms. He related that he was first noted to have a cardiac murmur detected 4 decades previously during a military service physical examination but that the murmur was not characterized further and that he served in the Vietnam conflict without functional limitation. The patient’s relevant medical history included rate-controlled atrial fibrillation, 90 pack-year tobacco use (3 packs daily between 21 and 51 years of age), dyslipidemia, systemic hypertension, type 2 diabetes mellitus, moderate chronic obstructive pulmonary disease, obstructive sleep apnea not currently treated, and gastrointestinal bleed caused by colon cancer treated with hemicolectomy 11 years earlier. There was no illicit drug use, but a remote history of heavy alcohol consumption was reported. Family history was unremarkable except that his father died at 55 years of age of myocardial infarction. Medications included aspirin 81 mg daily, warfarin 2 mg daily, losartan 50 mg daily, metoprolol tartrate 25 mg twice daily, simvastatin 10 mg daily, fenofibrate 48 mg daily, albuterol inhaler 90-μg puffs as needed, and gabapentin 300 mg 3 times daily. |
11,235 | Impact of obesity on cardiac metabolism, fibrosis, and function. | Obesity is a global pandemic with a huge burden on the healthcare system. Obesity is not only linked to the development of risk factors for atherosclerotic vascular disease but also has a strong association with ventricular hypertrophy, heart failure, atrial fibrillation, and stroke. Recent experimental and clinical studies have demonstrated that obesity is associated with cardiac dysfunction, adipokine dysregulation, and activation of the pro-fibrotic signaling pathways leading to cardiac fibrosis, which is a key structural change responsible for atrial fibrillation. Importantly, these also have been shown to be reversible with weight reduction strategies. This review discusses the alterations in cardiac metabolism and function due to obesity. In addition, it addresses the complex and not yet fully understood mechanisms underlying cardiac fibrosis, with a focus on atrial substrate predisposing to atrial fibrillation in obesity. |
11,236 | Clinical impact of atrial fibrillation in patients with the HeartMate II left ventricular assist device. | Atrial fibrillation (AF) is common in patients with the HeartMate II (HMII) left ventricular assist device (LVAD), but the impact of AF on clinical outcomes is uncertain.</AbstractText>This study sought to determine the effect of AF on outcomes in patients with the HMII LVAD.</AbstractText>Records of 106 patients who underwent HMII implantation at a single center were reviewed. The associations of paroxysmal atrial fibrillation (PAF) and persistent atrial fibrillation (PeAF) with survival, heart failure (HF) hospitalization, bleeding, and thromboembolism were examined using Kaplan-Meier survival analysis and Cox proportional hazards regression.</AbstractText>Mean age was 56.6 ± 11.4 years, 87.7% of the implants were intended as a bridge to transplantation, and median length of support was 217 days (range: 1 to 952 days). AF was present in 55 patients (51.9%); 36 patients (34.0%) had PAF and 19 (17.9%) had PeAF. Twenty-one patients (19.8%) died, and 18 (17.0%) were hospitalized for HF. There were 0.75 major bleeding events and 0.28 thromboembolic events per patient year of follow-up. PAF was not associated with increased mortality, HF hospitalization, bleeding, or thromboembolism. PeAF, however, was an independent predictor of the composite endpoint of death or HF hospitalization (hazard ratio: 3.54; 95% confidence interval: 1.52 to 8.25; p < 0.01). Although there was no increase in bleeding or thromboembolism, patients with AF had thromboembolic events at higher international normalized ratios (INRs).</AbstractText>Although PAF is not associated with worse outcomes in patients with the HMII LVAD, PeAF may be associated with increased mortality and HF hospitalization. Patients with AF also may have thromboembolic events at higher INR levels.</AbstractText>Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,237 | Exposures to conducted electrical weapons (including TASER® devices): how many and for how long are acceptable? | TASER(®) conducted electrical weapons (CEWs) are an important law-enforcement tool. The purposes of this study are a) to review recent literature regarding potential pathophysiological responses to applications of CEWs, and other related issues and b) to evaluate whether enough data exist to determine the acceptability of longer-duration (or repeated) exposures. This is a narrative review, using a multidisciplinary approach of analyzing reports from physiological, legal-medical, and police-strategy literature sources. In general, short-duration exposures to CEWs result in limited effects. Longer-duration or repeated exposures may be utilized with caution, although there are currently not enough data to determine the acceptability of all types of exposures. Data examined in the literature have inherent limitations. Appropriateness of specific types of CEW usage may be determined by individual police agencies, applying risk/benefit analyses unique to each organization. While more research is recommended, initial concepts of potential future long-duration or repeated CEW applications are presented. |
11,238 | Antiarrhythmic drug therapy for atrial fibrillation. | Atrial fibrillation (AF) is the most frequently encountered arrhythmia. Prevalence increases with advancing age and so as its associated comorbidities, like heart failure. Choice of pharmacologic therapy depends on whether the goal of treatment is maintaining sinus rhythm or tolerating AF with adequate control of ventricular rates. Antiarrhythmic therapy and conversion of AF into sinus rhythm comes with the side effect profile, and we should select best antiarrhythmic therapy, individualized to the patient. New antiarrhythmic drugs are being tested in clinical trials. Drugs that target remodeling and inflammation are being tested for their use as prevention of AF or as upstream therapy. |
11,239 | Determinants of left ventricular dysfunction after repair of chronic asymptomatic mitral regurgitation. | The evidence supporting early surgical intervention in patients with chronic asymptomatic mitral regurgitation (MR) is steadily accumulating. Although left ventricular (LV) enlargement and preoperative pulmonary hypertension are considered when deciding on surgical intervention, the threshold above which these factors influence clinical outcomes remains poorly defined.</AbstractText>One-hundred fifty asymptomatic patients of aged 59.3 ± 13.4 years underwent mitral valve repair of severe MR caused by myxomatous degeneration between 2001 and 2012. Mean preoperative left atrial diameter, LV end-systolic diameter (LVESD), and right ventricular systolic pressure were 41.2 ± 6.9 mm, 34.6 ± 5.4 mm, and 38.4 ± 11.8 mm Hg, respectively. Preoperative LV ejection fraction (LVEF) was greater than 60% in 136 (91%) patients, and none had preoperative atrial fibrillation. Clinical and echocardiographic follow-up averaged 3.3 years and extended to 9.1 years.</AbstractText>There were no perioperative deaths. Five-year survival and freedom from recurrent MR greater than or equal to 2+ were 93.4% ± 3.2% and 94.0% ± 3.2%, respectively. A threshold LVESD indexed to body surface area greater than 19 mm/m(2) (hazard ratio [HR], 3.5 ± 2.0; p = 0.03) and a preoperative right ventricular systolic pressure greater than 45 mm Hg (HR, 3.8 ± 12.1; p = 0.01) were independently associated with postoperative LV dysfunction, defined as a LVEF less than 60%.</AbstractText>Mitral valve repair can be performed with favorable early and late outcomes in patients with asymptomatic severe MR. The presence of minimal LV enlargement and preoperative pulmonary hypertension were associated with postoperative LV dysfunction in this otherwise healthy population. Mitral valve repair may be considered in asymptomatic patients with an indexed LVESD (ILVESD) greater than 19 mm/m(2) or preoperative right ventricular systolic pressure greater than 45 mm Hg.</AbstractText>Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,240 | Clinical aspects of inherited J-wave syndromes. | Presence of J-point elevation with rapidly ascending ST segment in the anterior leads of the 12-lead electrocardiogram has been generally considered a benign phenomenon. The concept of benign nature of J-waves has changed as data emerged on variants of J-waves that were associated with the increased risk of sudden cardiac death. Two specific inherited arrhythmia syndromes, such as Brugada syndrome and early repolarization syndrome, have been recognized that carry an increased risk for ventricular fibrillation. The current review is aimed at discussing the clinical aspects of these syndromes and the implications of incidental recognition of the J-waves in a randomly recorded electrocardiogram of asymptomatic subjects. |
11,241 | Insights into cardiac conduction system formation provided by HCN4 expression. | Specialized myocytes of the cardiac conduction system (CCS) are essential to coordinate sequential contraction of cardiac atria and ventricles. Anomalies of the CCS can result in lethal cardiac arrhythmias, including sick sinus syndrome and atrial or ventricular fibrillation. To develop future therapies and regenerative medicine aimed at cardiac arrhythmias, it is important to understand formation and function of distinct components of the CCS. Essential to this understanding is the development of CCS-specific markers. In this review, we briefly summarize available mouse models of CCS markers and focus on those involving the hyperpolarization cation-selective nucleotide-gated cation channel, HCN4, which selectively marks all components of the specialized CCS in adult heart. Recent studies have revealed, however, that HCN4 expression during development is highly dynamic in cardiac precursors. These studies have offered insights into the contributions of the first and second heart field to myocyte and conduction system lineages and suggested the timing of allocation of specific conduction system precursors during development. Altogether, they have highlighted the utility of HCN4 as a cell surface marker for distinct components of the CCS at distinct stages of development, which can be utilized to facilitate purification and characterization of CCS precursors in mouse and human model systems and pave the way for regenerative therapies. |
11,242 | Giant right atrium: an extreme case of idiopathic dilation of the right atrium. | An adult with a grossly dilated right atrium of unknown etiology is presented. The right atrial volume was estimated at more than 1,900 mL, with normal sized left atrium and ventricles. She presented in atrial fibrillation and right ventricular failure. She underwent subsequent reduction atrioplasty of the right atrium and tricuspid valve ring annuloplasty. Atrioplasty alone was unsuccessful in controlling the atrial fibrillation. Postoperatively, her course was complicated by pericardial space problems, eventually requiring a partial pericardiectomy. At her 2-year follow-up she was asymptomatic, although still in atrial fibrillation. |
11,243 | Clinical significance of a presystolic wave on Doppler examination of the left ventricular outflow tract. | A presystolic wave (PSW) is commonly seen on Doppler examination of the left ventricular outflow tract (LVOT), but is little studied. We conducted a retrospective study to assess the prevalence of the PSW, correlations with various Doppler parameters, and its clinical significance. Two hundred echocardiograms, 100 with ejection fraction (EF) >55% and 100 with EF <45%, were reviewed. Mitral inflow velocities, septal annular velocities, LVOT, and PSW velocities were measured. Major adverse cardiovascular events (MACE [death, heart failure hospitalization, atrial fibrillation, and stroke]) were compared between those with and without a PSW, in both EF groups. Mean age was 58 ± 15 years; 56% were men and 69% were African-American. PSW prevalence was similar between normal (68%) and reduced EF groups (62%). However, its velocity was less in the low EF group (37 ± 10 vs 48 ± 16 cm/s, p <0.0001). In subjects with normal EF PSW velocity correlated with mitral A velocity (rho = 0.43, p = 0.0003). In subjects with reduced EF the association with A velocity was not significant (rho = 0.22, p = 0.09), but there was a significant association with annular a' velocity (rho = 0.38, p = 0.002). Over a mean follow-up of 1.7 ± 0.3 years, 57 subjects (28%) experienced MACE. Those without a PSW had more MACE (39% vs 23%, p = 0.02); PSW absence remained predictive of MACE after adjustment for multiple variables, especially in patients with reduced EF. In conclusion, PSW is common in the LVOT. Its presence and magnitude are associated with measures of atrial contraction. Its absence is associated with increased rates of adverse events, especially in patients with low EF. |
11,244 | Atrial fibrillation promotion with long-term repetitive obstructive sleep apnea in a rat model. | Obstructive sleep apnea (OSA) importantly contributes to the occurrence of atrial fibrillation (AF) in humans, but the mechanisms are poorly understood. Experimental research has provided insights into AF promotion by acute OSA episodes. However, patients with OSA usually have frequent nocturnal episodes for some time before manifesting AF.</AbstractText>The goal of this study was to test the hypothesis that repetitive OSA causes cardiac remodeling that predisposes to AF.</AbstractText>We mimicked OSA by using a mechanical ventilator and closing the airway at end-expiration with a 3-way stopcock (OSA rats). Matched control groups included rats with the ventilator stopped but airway left open (open airway rats) and continuously ventilated rats (sham rats). OSA rats were exposed to 20 consecutive 2-min cycles of 40 s of apnea/80 s of ventilation per day, 5 days per week for 4 weeks.</AbstractText>OSA significantly increased the duration of AF from (median [interquartile range]) 2.6 s [1.9 s to 8.9 s] (shams) and 16 s [1.8 s to 93 s] (open airway) to 49s [34 s to 444 s]. AF inducibility increased to 56% (9 of 16) of OSA rats; this is up from 15% (2 of 13) and 13% (2 of 15) in open airway and sham rats, respectively (p < 0.05). OSA rats exhibited substantial atrial conduction slowing on optical mapping, along with connexin-43 down-regulation on both quantitative immunofluorescence (expression reduced by 58% vs sham rats) and Western blot (reduced by 38%), as well as increased atrial fibrous tissue content (by 71%). OSA also caused left ventricular hypertrophy, dilation, and diastolic dysfunction and enhanced AF inducibility during superimposed acute OSA episodes to 82.4% of rats.</AbstractText>Chronically repeated OSA episodes cause AF-promoting cardiac remodeling, with conduction abnormalities related to connexin dysregulation and fibrosis playing a prominent role. This novel animal model provides mechanistic insights into an important clinical problem and may be useful for further exploration of underlying mechanisms and therapeutic approaches.</AbstractText>Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,245 | Do differences in early hemodynamic performance of current generation biologic aortic valves predict outcomes 1 year following surgery? | Small early postoperative hemodynamic differences were noted in a randomized comparison of 3 current-generation bioprosthetic aortic valves. Whether these differences persist and influence clinical outcomes 1 year following implantation is unknown.</AbstractText>Three hundred adults with severe aortic stenosis undergoing valve replacement were randomized to receive the Epic (St Jude, St Paul, Minn) (n = 99), Magna (Edwards LifeSciences Inc, Irvine, Calif) (n = 100), or Mitroflow (Sorin Biomedica Spa, Saluggio, Italy) (n = 101) bioprostheses. Hemodynamic valve performance was examined by echocardiography at 1 year, and clinical outcomes were assessed in 241 patients (79 Epic, 77 Magna, and 85 Mitroflow; P = .437).</AbstractText>Mean age was 75 ± 8 years and 164 were men (68%). Between dismissal and 1 year there were 9 deaths (3.7%) (Epic: 3.7%, Magna: 5.0%, and Mitroflow: 2.3%; P = .654), 6 episodes of heart failure (2.5%) (Epic: 1.3%, Magna: 1.3%, and Mitroflow: 5.8%; P = .265), 27 instances of atrial fibrillation/flutter (11.2%) (Epic: 8.1%, Magna: 11.0%, and Mitroflow: 7.9%; P = .577) and no strokes/transient ischemic attacks. One-year echocardiography demonstrated small hemodynamic differences between Epic, Magna, and Mitroflow bioprostheses in mean gradient (15.2 ± 5.5, 12.3 ± 4.3, and 16.2 ± 5.7 mm Hg, respectively; P < .001) and indexed aortic valve area (0.93 ± 0.28, 1.04 ± 0.28, and 0.96 ± -0.26 cm(2)/m(2), respectively; P = .015). Several early trends persisted when stratifying data by echocardiographic annulus diameter, universal annulus size, and implant size, particularly with annular size ≥23 mm. Overall left ventricular mass index regression between dismissal and 1 year was -16.5 ± 28.1 g/m(2), and was similar among groups (P = .262). There were no aortic valve reoperations.</AbstractText>Despite midterm persistence of small hemodynamic differences amongst current-generation porcine and pericardial aortic valves, our prospective randomized comparison reveals that clinical outcomes and mass regression are equivalent between devices at 1 year. These encouraging trends must continue to be assessed during longitudinal follow-up.</AbstractText>Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
11,246 | Impact of flow and left ventricular strain on outcome of patients with preserved left ventricular ejection fraction and low gradient severe aortic stenosis undergoing aortic valve replacement. | The prognostic implications of flow, assessed by stroke volume index (SVi), and left ventricular (LV) global longitudinal strain on survival of patients with low-gradient severe aortic stenosis (AS) and preserved LV ejection fraction are debated. The aim of this study was to evaluate the impact of flow and LV global longitudinal strain on survival in these patients treated with aortic valve replacement (AVR). Patients with low-gradient severe AS with preserved LV ejection fraction treated with AVR (n = 134, mean age 76 ± 10 years, 50% men) were included in the present study. Aortic valve hemodynamics and LV function were assessed with 2-dimensional, Doppler and speckle-tracking echocardiography before AVR. Patients were dichotomized on the basis of low (SVi ≤35 ml/m(2)) or normal (SVi >35 ml/m(2)) flow and impaired (>-15%) or more preserved (≤-15%) global longitudinal strain. The end point was all-cause mortality. During a median follow-up period of 1.8 years (interquartile range 0.5 to 3) after AVR, 26 patients (19.4%) died. Survival was better for patients with SVi >35 ml/m(2) or global longitudinal strain ≤-15% compared with those with SVi ≤35 ml/m(2) or global longitudinal strain >-15% (log-rank p = 0.01). Atrial fibrillation (hazard ratio 5.40, 95% confidence interval 1.81 to 16.07, p = 0.002) and chronic kidney disease (hazard ratio 3.67, 95% confidence interval 1.49 to 9.06, p = 0.005) were the clinical variables independently associated with all-cause mortality. The addition of global longitudinal strain (chi-square = 19.87, p = 0.029, C-statistic = 0.74) or SVi (chi-square = 29.62, p <0.001, C-statistic = 0.80) to a baseline model including atrial fibrillation and chronic kidney disease (chi-square = 14.52, C-statistic = 0.68) improved risk stratification of these patients. In conclusion, flow and LV global longitudinal strain are independently associated with survival after AVR in patients with low-gradient severe AS with preserved LV ejection fraction. |
11,247 | Comparison of age (<75 Years versus ≥75 Years) to risk of ventricular tachyarrhythmias and implantable cardioverter defibrillator shocks (from the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy). | There are limited data regarding the effect of age on the risk of ventricular tachyarrhythmias (VTAs). The present study was designed to compare the risk for VTAs in young and older patients with left bundle branch block (LBBB) and mildly symptomatic heart failure who receive device therapy. The risk of the first ventricular tachycardia (VT) or ventricular fibrillation (VF) event and the risk of first appropriate implantable cardioverter defibrillator (ICD) shock was compared between young (<75 years, n = 1,037) and older (≥75 years, n = 227) patients with LBBB enrolled in Multicenter Automatic Implantation Trial with Cardiac Resynchronization Therapy. The cumulative incidence of a first VTA through 2 years of follow-up was significantly lower in older patients than in younger patients. Multivariate analysis showed that older patients experienced a significantly lower risk of VT/VF (hazard ratio 0.38, 95% confidence interval 0.22 to 0.64, p <0.001) and a significantly lower risk of appropriate ICD shocks (hazard ratio 0.37, 95% confidence interval 0.17 to 0.82, p = 0.014) compared with younger patients. Each increasing decade of life was associated with a 19% (p = 0.002) and 22% (p = 0.018) reduction in the risk of VT/VF and appropriate ICD shocks, respectively. The lower risk of VT/VF and appropriate ICD shocks in older patients was evident in patients implanted with an ICD only and in those implanted with a cardiac resynchronization therapy with defibrillator. In conclusion, in patients with LBBB and mild symptoms of heart failure, aging is associated with a significant decrease in the incidence of VT/VF and ICD shocks. |
11,248 | Mid-regional proadrenomedullin levels predict recurrence of atrial fibrillation after catheter ablation. | We evaluated the prognostic value of mid-regional proadrenomedullin (MR-proADM) in atrial fibrillation (AF) patients undergoing radiofrequency ablation.</AbstractText>Plasma concentrations of MR-proADM were measured at baseline and after 12months in 87 AF patients in whom radiofrequency ablation was performed. The association between MR-proADM and AF recurrence was tested by univariable and multivariable Cox models.</AbstractText>In all 87 patients radiofrequency ablation was successfully performed. Of the total population 54% had paroxysmal AF. The mean left ventricular ejection fraction was 54% (minimum 25%). After 12months of follow-up, 71% of the patients were free of AF recurrence. At baseline, mean MR-proADM in the total population was 0.72nmol/l±0.22. Patients with AF recurrence had significantly higher baseline MR-proADM (0.89nmol/l±0.29) as compared with patients without AF recurrence (0.65nmol/l±0.14; p<0.001). After 12months, mean MR-proADM plasma concentration remained higher in patients with AF recurrence (0.81nmol/l±0.22 as compared with patients free of AF 0.54nmol/l±0.20; p<0.001). Receiver operating characteristic (ROC) curve analysis for MR-proADM yields a specificity of 98% and a sensitivity of 64% with an optimal cut-off value of 0.82nmol/l to predict recurrence of AF after catheter ablation. In the logistic regression analysis only MR-proADM remained independently predictive for AF recurrence.</AbstractText>This is the first study revealing the association between MR-proADM elevation before ablation and poor outcomes after ablation of AF. Larger studies are needed to validate these results.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,249 | Long-term outcome of multiform premature ventricular complexes in structurally normal heart. | Multiform premature ventricular complexes (PVCs) are common electrocardiographic abnormalities in patients with structurally normal hearts. However, the prognostic value of these complexes remains unclear. This study aimed to clarify the role of PVC polymorphism in predicting adverse outcomes.</AbstractText>We examined the database for 24-hour electrocardiography monitoring between January 1, 2002 and December 31, 2004. We analyzed 3351 individuals with apparently normal hearts. Kaplan-Meier curves and multivariate Cox proportional hazards models were employed to estimate the effect of multiform PVC and uniform PVC on the number of incident adverse events. Average follow-up time was 10±1years. Patients with multiform PVC were older and had a higher prevalence of comorbidities. In multivariate analysis, patients with multiform PVC had an increased incidence of mortality (hazard ratio [HR]: 1.642, 95% confidence interval [CI]: 1.327-2.031), hospitalization (HR: 1.196, 95% CI: 1.059-1.350), cardiovascular hospitalization (HR: 1.289, 95% CI: 1.030-1.613), new-onset heart failure (HF; HR: 1.456, 95% CI: 1.062-1.997), transient ischemic accident (HR: 1.411, 95% CI 1.063-1.873), and new-onset atrial fibrillation (AF; HR: 1.546, 95% CI: 1.058-2.258) compared to the group without PVC. Patients with multiform PVC had a higher rate of mortality (HR: 1.231, 95% CI: 1.033-1.468) and all cause-hospitalization (HR: 1.147, 95% CI: 1.025-1.283) compared with patients with uniform PVC.</AbstractText>The presence of multiform PVC was associated with a higher incidence of mortality, hospitalization, transient ischemic attack, new-onset AF, and new-onset HF independent of other clinical risk factors.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
11,250 | Causes of in-hospital cardiac arrest - incidences and rate of recognition. | Do emergency teams (ETs) consider the underlying causes of in-hospital cardiac arrest (IHCA) during advanced life support (ALS)? In a 4.5-year prospective observational study, an aetiology study group examined 302 episodes of IHCA. The purpose was to investigate the causes and cause-related survival and to evaluate whether these causes were recognised by the ETs.</AbstractText>In 258 (85%) episodes, the cause of IHCA was reliably determined. The cause was correctly recognised by the ET in 198 of 302 episodes (66%). In the majority of episodes, cardiac causes (156, 60%) or hypoxic causes (51, 20%) were present. The cause-related survival was 30% for cardiac aetiology and 37% for hypoxic aetiology. The initial cardiac rhythm was pulseless electrical activity (PEA) in 144 episodes (48%) followed by asystole in 70 episodes (23%) and combined ventricular fibrillation/ventricular tachycardia (VF/VT) in 83 episodes (27%). Seventy-one patients (25%) survived to hospital discharge. The median delay to cardiopulmonary resuscitation (CPR) was 1min (inter-quartile range 0-1min).</AbstractText>Various cardiac and hypoxic aetiologies dominated. In two-thirds of IHCA episodes, the underlying cause was correctly identified by the ET, i.e. according to the findings of the aetiology study group.</AbstractText>Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.</CopyrightInformation> |
11,251 | Update on Cardiac Resynchronisation Therapy for Heart Failure. | Cardiac resynchronisation therapy (CRT) is well accepted therapy for the treatment of symptomatic systolic heart failure in defined patient subgroups. Large clinical trials over the past 20 years have shown that patients with a left ventricular (LV) systolic dysfunction and interventricular conduction delay benefit from this therapy. Recent advances in this field include the expansion indications for CRT to patients with mild heart failure and to those with a mildly depressed ejection fraction that require frequent right ventricular pacing. In addition, although CRT guidelines have included indications in atrial fibrillation, it is now clear that this is most effective when pacing is utilised nearly 100 % of the time, often requiring atrioventricular (AV) junction ablation. Strategies for optimising LV lead placement based on identifying late mechanical contraction or electrical delay are promising for maximising CRT response. Finally, the role of routine AV delay optimisation is no longer recommended based on the results of multicentre trials. |
11,252 | Assessment of health-related quality of life in a greek symptomatic population with atrial fibrillation: correlation with functional status and echocardiographic indices. | Atrial fibrillation (AF) is known to have an unfavorable impact on quality of life. The purpose of this study was to assess the health-related quality of life (HRQOL) in a symptomatic population with AF seeking medical advice in a tertiary hospital, as well as to explore the relationship between HRQOL, functional status, and echocardiographic indices of left ventricular (LV) systolic and diastolic function.</AbstractText>The study sample consisted of 108 symptomatic patients suffering from AF who presented in the emergency department or were admitted to the cardiology department in an urban Greek tertiary hospital between January 1 and May 31, 2012. HRQOL was assessed using the SF-36 and EQ-5D instruments.</AbstractText>In the study sample, AF was newly diagnosed in 16.5% of the patients, paroxysmal/persistent in 43.6% and permanent in 39.9%. The mean levels of physical and mental summary components of the SF-36 were 40.28 and 40.89, respectively. The EQ-VAS mean score was 59.63%, while the EQ-5D Europe VAS index and the York A1 Tariff index were 0.586 and 0.547, respectively. Reliability analysis found Cronbach's to be 0.890 for the SF-36 and 0.701 for the EQ-5D. Convergent validity was proved to be at satisfactory levels. Impaired HRQOL was associated with worse NYHA class and echocardiographic indices of impaired LV systolic and diastolic function. Apart from higher NYHA class, other predisposing factors for lower HRQOL were female sex, advanced age, low physical activity, and higher levels of brain natriuretic peptide.</AbstractText>Symptomatic AF patients report impaired HRQOL. Functional status and echocardiographic indices of LV systolic and diastolic function appear to affect HRQOL significantly in these patients. The SF-36 and the EQ-5D are shown to be reliable and valid instruments in assessing HRQOL in patients with AF.</AbstractText> |
11,253 | Influence of renal function on mortality and ventricular arrhythmias in patients undergoing first implantable cardioverter-defibrillator generator replacement. | Impaired renal function is associated with increased mortality among patients with implantable cardioverter-defibrillators (ICDs). The relationship between renal function at time of ICD generator replacement and subsequent appropriate ICD therapies is not known.</AbstractText>We identified 441 patients who underwent first ICD generator replacement between 2000 and 2011 and had serum creatinine measured within 30 days of their procedure. Patients were divided into tertiles based on estimated glomerular filtration rate (eGFR). Adjusted Cox proportional hazard and competing risk models were used to assess relationships between eGFR and subsequent mortality and appropriate ICD therapy. Median eGFR was 37.6, 59.3, and 84.8 mL/min/1.73 m(2) for tertiles 1-3, respectively. Five-year Kaplan-Meier survival probability was 34.8%, 61.4%, and 84.5% for tertiles 1-3, respectively (P < 0.001). After multivariable adjustment, compared to tertile 3, worse eGFR tertile was associated with increased mortality (HR 2.84, 95% CI [1.36-5.94] for tertile 2; HR 3.84, 95% CI [1.81-8.12] for tertile 1). At 5 years, 57.0%, 58.1%, and 60.2% of patients remained free of appropriate ICD therapy in tertiles 1-3, respectively (P = 0.82). After adjustment, eGFR tertile was not associated with future appropriate ICD therapy. Results were unchanged in an adjusted competing risk model accounting for death.</AbstractText>At time of first ICD generator replacement, lower eGFR is associated with higher mortality, but not with appropriate ICD therapies. The poorer survival of ICD patients with reduced eGFR does not appear to be influenced by arrhythmia status, and there is no clear proarrhythmic effect of renal dysfunction, even after accounting for the competing risk of death.</AbstractText>© 2014 Wiley Periodicals, Inc.</CopyrightInformation> |
11,254 | A pilot study to assess benefit of atrial rhythm control after cardiac resynchronization therapy and atrioventricular node ablation. | Atrial fibrillation (AF) is frequently comorbid in patients receiving cardiac resynchronization therapy (CRT), and suppression is typically difficult. Herein, we sought to understand the benefit of atrial rhythm control in the setting of ventricular rate and regularity control induced by atrioventricular node (AVN) ablation.</AbstractText>Fifty-two patients with heart failure, persistent AF, left ventricular (LV) ejection fraction <35%, and left bundle branch block underwent cardiac resynchronization therapy (CRT) + AVN ablation, and were randomized to one of the following groups: (1) Atrial Rhythm Control (ARC); (2) AF. Patients were subsequently followed for up to 1 year.</AbstractText>Similar numbers of patients in each group were lost to follow-up or have withdrawn (ARC two; AF three). Rhythm control in four patients in the ARC group was inadequate. Among the remaining patients, the incidence of death (ARC=1, AF=2) or left ventricular assist device +/- transplantation (ARC=2, AF=1) were similar. Among the remaining patients (ARC 16, AF 19), at 1 year, there were no significant differences in CRT response rate, Minnesota Living with Heart Failure survey score, 6-minute hall walk distance, ventricular tachyarrhythmia occurrence, or LV dimensions. A significantly higher hospital encounter rate among ARC patients was attributable to efforts to maintain uniform atrial rhythm.</AbstractText>In this pilot study, no incremental benefit for ARC was apparent. A larger study will be necessary to adequately examine these issues.</AbstractText>© 2014 Wiley Periodicals, Inc.</CopyrightInformation> |
11,255 | Members of the emergency medical team may have difficulty diagnosing rapid atrial fibrillation in Wolff-Parkinson-White syndrome. | Atrial fibrillation (AF) in patients with Wolff-Parkinson-White (WPW) syndrome is potentially life-threatening as it may deteriorate into ventricular fibrillation. The aim of this study was to assess whether the emergency medical team members are able to diagnose AF with a rapid ventricular response due to the presence of atrioventricular bypass tract in WPW syndrome.</AbstractText>The study group consisted of 316 participants attending a national congress of emergency medicine. A total of 196 questionnaires regarding recognition and management of cardiac arrhythmias were distributed. The assessed part presented a clinical scenario with a young hemodynamically stable man who had a 12-lead electrocardiogram performed in the past with signs of pre-excitation, and who presented to the emergency team with an irregular broad QRS-complex tachycardia.</AbstractText>A total of 71 questionnaires were filled in. Only one responder recognized AF due to WPW syndrome, while 5 other responders recognized WPW syndrome and paroxysmal supraventricular tachycardia or broad QRS-complex tachycardia. About 20% of participants did not select any diagnosis, pointing out a method of treatment only. The most common diagnosis found in the survey was ventricular tachycardia/broad QRS-complex tachycardia marked by approximately a half of the participants. Nearly 18% of participants recognized WPW syndrome, whereas AF was recognized by less than 10% of participants.</AbstractText>Members of emergency medical teams have limited skills for recognizing WPW syndrome with rapid AF, and ventricular tachycardia is the most frequent incorrect diagnosis.</AbstractText> |
11,256 | Risk stratification in patients with Brugada syndrome without previous cardiac arrest – prognostic value of combined risk factors. | Risk stratification in patients with Brugada syndrome for primary prevention of sudden cardiac death is still an unsettled issue. A recent consensus statement suggested the indication of implantable cardioverter defibrillator (ICD) depending on the clinical risk factors present (spontaneous type 1 Brugada electrocardiogram (ECG) [Sp1], history of syncope [syncope], and ventricular fibrillation during programmed electrical stimulation [PES+]). The indication of ICD for the majority of patients, however, remains unclear.</AbstractText>A total of 218 consecutive patients (211 male; aged 46 ± 13 years) with a type 1 Brugada ECG without a history of cardiac arrest who underwent evaluation for ICD including electrophysiological testing were examined retrospectively. During a mean follow-up period of 78 months, 26 patients (12%) developed arrhythmic events. On Kaplan-Meier analysis patients with each of Sp1, syncope, or PES+ suffered arrhythmic events more frequently (P=0.018, P<0.001, and P=0.003, respectively). On multivariate analysis Sp1 and syncope were independent predictors of arrhythmic events. When dividing patients according to the number of these 3 risk factors present, patients with 2 or 3 risk factors experienced arrhythmic events more frequently than those with 0 or 1 risk factor (23/93 vs. 3/125; P<0.001).</AbstractText>Syncope, Sp1, and PES+ are important risk factors and the combination of these risks well stratify the risk of later arrhythmic events.</AbstractText> |
11,257 | Treating Heart Failure with Preserved Ejection Fraction Related to Arterial Stiffness. Can we Kill Two Birds With One Stone? | Heart failure with preserved ejection fraction (HFpEF). Arterial hypertension (AH), arterial stiffness (AS), older age, and female gender are the main determinants of HFpEF, but several cardiac or extra-cardiac pathologies are also possible causes. The combined ventricular-vascular stiffening (abnormal left atrium-left ventricle coupling related to AS) is the main contributor of the increased prevalence of HFpEF in elderly persons, particularly elderly women, and in younger persons with AH. The hospitalization and mortality rates of HFpEF are similar to those of heart failure with reduced EF (HFrEF). However, although the prognosis of HFrEF has been substantially improved during the last 2 decades, the effective treatment of HFpEF remains an unmet need. Regimens effective in HFrEF have no substantial effect on HFpEF, because of different pathophysiologies of the 2 syndromes. Pipeline drugs seem promising, but it will take some years before they are commercially available. Aggressive treatment of noncardiac comorbidities seems to be the only option at hand. Treatment of anaemia, sleep disorders, chronic kidney disease (CKD), non-alcoholic fatty liver (NAFLD), atrial fibrillation, diabetes, and careful use of diuretics to reduce preload are effective to some degree. Statin treatment, despite the presence of dyslipidaemia, deserves special attention because it has been proven, mainly in small studies or post hoc analyses of trials, that it offers a substantial improvement in quality of life and a reduction in mortality rates. We need to urgently utilize these recourses to relieve a considerable part of the general population suffering from HFpEF, a deadly disease. |
11,258 | Characteristics, complications, and gaps in evidence-based interventions in rheumatic heart disease: the Global Rheumatic Heart Disease Registry (the REMEDY study). | Rheumatic heart disease (RHD) accounts for over a million premature deaths annually; however, there is little contemporary information on presentation, complications, and treatment.</AbstractText>This prospective registry enrolled 3343 patients (median age 28 years, 66.2% female) presenting with RHD at 25 hospitals in 12 African countries, India, and Yemen between January 2010 and November 2012. The majority (63.9%) had moderate-to-severe multivalvular disease complicated by congestive heart failure (33.4%), pulmonary hypertension (28.8%), atrial fibrillation (AF) (21.8%), stroke (7.1%), infective endocarditis (4%), and major bleeding (2.7%). One-quarter of adults and 5.3% of children had decreased left ventricular (LV) systolic function; 23% of adults and 14.1% of children had dilated LVs. Fifty-five percent (n = 1761) of patients were on secondary antibiotic prophylaxis. Oral anti-coagulants were prescribed in 69.5% (n = 946) of patients with mechanical valves (n = 501), AF (n = 397), and high-risk mitral stenosis in sinus rhythm (n = 48). However, only 28.3% (n = 269) had a therapeutic international normalized ratio. Among 1825 women of childbearing age (12-51 years), only 3.6% (n = 65) were on contraception. The utilization of valvuloplasty and valve surgery was higher in upper-middle compared with lower-income countries.</AbstractText>Rheumatic heart disease patients were young, predominantly female, and had high prevalence of major cardiovascular complications. There is suboptimal utilization of secondary antibiotic prophylaxis, oral anti-coagulation, and contraception, and variations in the use of percutaneous and surgical interventions by country income level.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
11,259 | [The pacemaker and implantable cardioverter-defibrillator registry of the Italian Association Arrhythmology Cardiac Pacing and cardiac pacing - annual report 2013]. | The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2013 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers.</AbstractText>The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards.</AbstractText>PM Registry: data about 25 419 PM implantations were collected (19 134 first implant and 6285 replacements). The number of collaborating centers was 275. Median age of treated patients was 80 years (74 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 43.6% of first PM implants, sick sinus syndrome in 24.7%, atrial fibrillation plus bradycardia in 12.9%, other in 18.8%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (23.2% of first implants). Use of single-chamber PMs was reported in 27.2% of first implants, of dual-chamber PMs in 62.6%, of PMs with cardiac resynchronization therapy (CRT) in 1.8%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 8.4%. ICD Registry: data about 16 519 ICD implantations were collected (11 474 first implants and 5045 replacements). The number of collaborating centers was 430. Median age of treated patients was 71 years (63 quartile I; 77 quartile III). Primary prevention indication was reported in 76% of first implants, secondary prevention in 24.0% (cardiac arrest in 7.8%). A single-chamber ICD was used in 27.2% of first implants, dual-chamber in 35.9% and biventricular in 36.8%.</AbstractText>The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a constant increase in prophylactic and biventricular ICD use, reflecting a favorable adherence to trials and guidelines in clinical practice.</AbstractText> |
11,260 | Oral carvedilol in escalating doses in the acute treatment of atrial fibrillation. | To study the efficacy of oral carvedilol in acute treatment of atrial fibrillation (AF) with fast ventricular rate.</AbstractText>In an open-label, single-arm trial, oral carvedilol was administered to 35 patients of AF in escalating doses from 3.125 mg o.d. to 12.5 mg b.i.d.</AbstractText>A successful result was seen in 25 patients (71.4%) with 4 converting to sinus rhythm, rate control to less than 90 bpm in 16 and a 20% rate reduction in 5 patients. Two patients developed hypotension needing withdrawal of the drug.</AbstractText>Escalating doses of oral carvedilol can be effectively and safely used in the acute treatment of AF with fast ventricular rate.</AbstractText> |
11,261 | Re-entry using anatomically determined isthmuses: a curable ventricular tachycardia in repaired congenital heart disease. | Ventricular tachycardia (VT) is an important cause of late morbidity and mortality in repaired congenital heart disease. The substrate often includes anatomic isthmuses that can be transected by radiofrequency catheter ablation similar to isthmus block for atrial flutter. This study evaluates the long-term efficacy of isthmus block for treatment of re-entry VT in adults with repaired congenital heart disease.</AbstractText>Thirty-four patients (49±13 years; 74% male) with repaired congenital heart disease who underwent radiofrequency catheter ablation of VT in 2 centers were included. Twenty-two (65%) had a preserved left and right ventricular function. Patients were inducible for 1 (interquartile range, 1-2) VT, median cycle length: 295 ms (interquartile range, 242-346). Ablation aimed to transect anatomic isthmuses containing VT re-entry circuit isthmuses. Procedural success was defined as noninducibility of any VT and transection of the anatomic isthmus and was achieved in 25 (74%) patients. During long-term follow-up (46±29 months), all patients with procedural success (18/25 with internal cardiac defibrillators) were free of VT recurrence but 7 of 18 experienced internal cardiac defibrillator-related complications. One patient with procedural success and depressed cardiac function received an internal cardiac defibrillator shock for ventricular fibrillation. None of the 18 patients (12/18 with internal cardiac defibrillators) with complete success and preserved cardiac function experienced any ventricular arrhythmia. In contrast, VT recurred in 4 of 9 patients without procedural success. Four patients died from nonarrhythmic causes.</AbstractText>In patients with repaired congenital heart disease with preserved ventricular function and isthmus-dependent re-entry, VT isthmus ablation can be curative.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,262 | Carbon monoxide-releasing molecules attenuate postresuscitation myocardial injury and protect cardiac mitochondrial function by reducing the production of mitochondrial reactive oxygen species in a rat model of cardiac arrest. | The objective of this study is to examine whether carbon monoxide-releasing molecules (CORMs) can decrease the generation of excessive reactive oxygen species (ROS) in cardiac mitochondria, thereby protecting against postresuscitation myocardial injury and cardiac mitochondrial dysfunction after resuscitation in a rat model of ventricular fibrillation (VF), and further investigated the underlying mechanism. Rats suffered 8 minutes of untreated VF and resuscitation and were randomized into the control group with vehicle infusion and the CORM group with CO-releasing molecule 2 (CORM2) treatment. Animals in the Sham group were instrumented without induced VF and resuscitation. Effects of CORM2 on cardiac function, myocardial oxidative stress, cardiac mitochondrial function, and mitochondrial ROS generation were assessed. Moreover, to further evaluate the direct effect of CORM2 on cardiac mitochondria isolated from resuscitated rats, we measured mitochondrial function and ROS generation when isolated cardiac mitochondria were directly incubated with different concentrations of (CORM2). Compared with the Sham group, the control and CORM groups demonstrated impaired cardiac function, increased myocardial injury, and aggravated mitochondrial damage. CORM2 improved cardiac performance and attenuated myocardial damage and oxidative stress in resuscitated rats. Additionally, animals with CORM2 treatment showed the decreased generation of cardiac mitochondrial ROS, alleviated mitochondrial injury, and preserved mitochondrial function and complex activities when compared with the control group. In isolated cardiac mitochondria incubated with CORM2, low concentrations of CORM2 (20 μmol/L) mildly uncoupled mitochondrial respiration, leading to reduced mitochondrial ROS production. In contrast, high concentrations of CORM2 (60 μmol/L) resulted in the reverse effect presumably due to its excessive uncoupling action. These findings suggest that CORM2 attenuates oxidative stress of the heart and improves cardiac function after resuscitation. The mechanism was probably that CO, the product of CORM2, reduces the production of cardiac mitochondrial ROS and thereby attenuates mitochondrial injury and dysfunction during the postresuscitation period, due to the transient uncoupling of mitochondrial respiration. |
11,263 | Delayed uptake and washout of contrast in non-viable infarcted myocardium shown with dynamic computed tomography. | Assessment of ischemic but potentially viable myocardium plays an important role in the planning of coronary revascularization. Until now SPECT, PET, and MRI have been used to identify viable myocardium. Computed tomography (CT) is increasingly used to diagnose coronary atherosclerosis.</AbstractText>To evaluate the feasibility of CT enhancement as a viability marker by investigating myocardial contrast distribution over time in pigs with experimentally induced antero-septal myocardial infarctions.</AbstractText>Twelve pigs were subjected to 60 min of balloon occlusion of the left anterior descending artery, followed by removal of the balloon and reperfusion. Four pigs died due to refractory ventricular fibrillation. After 6 weeks, dynamic cardiac CT was performed assessing both wall motion and contrast attenuation. Measurements of attenuation values in Hounsfield units (HU) in the infarct zone and the normal lateral wall were performed at 20 s, and 1, 3, 5, 8 and 12 min after contrast injection.</AbstractText>We found highly significant differences in attenuation values between the two zones at all-time points except t =1 min (ANOVA P=0.85). The normal myocardium showed higher uptake- and washout-rates of contrast than the infarct zone (84±15 vs. 58±8 at 20 s, P=0.0001 and 27±12 vs. 81±13 at 12 min, P=0.0001). Specifically, the ratio between early (20 s) and late (12 min) uptake is a valid marker of viable myocardium. In all animals this ration was above one in the normal zone and below one in the infarct zone.</AbstractText>Delayed infarct related uptake and washout of contrast shows promise for future clinical application of CT in a combined assessment of coronary atherosclerosis and myocardial viability.</AbstractText> |
11,264 | [CHADS₂versus CHA₂DS₂-VASc scoring systems for predicting left atrial thrombus in patients with nonvalvular atrial fibrillation]. | To assess the correlation of CHADS₂and CHA₂DS₂-VASc scores for left atrial thrombus in patients with nonvalvular atrial fibrillation and the differences in the results between the two scoring systems.</AbstractText>A total of 397 patients with nonvalvular atrial fibrillation were enrolled in this study. The CHADS₂and CHA2DS2-VASc scoring systems were used for evaluating the risk of left atrial thrombus and their differences in the scores and risk stratifications were compared. The correlation of CHADS₂ and CHA₂DS₂-VASc scores with left atrial thrombus was analyzed.</AbstractText>The average score of CHA₂DS₂-VASc was significantly higher than that of CHADS₂in these patients (1.37 ± 1.19 vs 0.63 ± 0.78, P<0.001). The proportion of high-risk group was significantly higher (P<0.001) while that of low-risk group significantly lower as stratified by CHA₂DS₂-VASc scores than by CHADS₂scores (P<0.001). Transesophageal echocardiography detected left atrial thrombus in 44 of the total patients. The prevalence of left atrial thrombus increased significantly with a higher risk stratification by CHADS₂or CHA₂DS₂-VASc scores (P<0.05). Univariate analysis showed that female gender, age ≥ 65 years, left atrium diameter ≥ 38 mm, left ventricular ejection fraction ≤ 40%, hypertension, diabetes, coronary heart disease, stroke history, CHADS₂≥ 2, and CHA₂DS₂-VASc ≥ 2 were all correlated with left atrial thrombus, but multivariate logistic analysis identified only CHA₂DS₂-VASc ≥ 2 as the independent risk factor for left atrial thrombus (OR=9.85, 95% CI: 2.178-44.542, P < 0.01).</AbstractText>The average score of CHA₂DS₂-VASc is higher than that of CHADS₂and has better predictive ability for left atrial thrombus.</AbstractText> |
11,265 | Non-invasive imaging in atrial fibrillation: focus on prognosis and catheter ablation. | Imaging identifies patients with high-risk phenotype among the general population with atrial fibrillation, such as the presence of structural and valvular heart disease, which are both related to adverse outcome. Imaging is also potentially important for prediction of success of catheter ablation. Specifically, patients with larger left atrial size, reduced left atrial function and increased left atrial fibrosis content are more likely to experience atrial fibrillation recurrences after ablation. Routine and advanced echocardiographic imaging techniques and multi-detector row computed tomography and magnetic resonance imaging can provide detailed information. Currently, imaging techniques are not able to predict success on an individual basis, but it does permit identification of patients with high versus low risk of atrial fibrillation recurrence after ablation. Finally, imaging can be performed after ablation to demonstrate beneficial effects of restoration of sinus rhythm, including left atrial reverse remodelling and improvement in left atrial or ventricular function. All these issues are discussed in the current review. |
11,266 | Neuroprotective effect of Shenfu Injection () following cardiac arrest in pig correlates with improved mitochondrial function and cerebral glucose uptake. | To test whether Shenfu Injection (, SFI) might attenuate the impact of cerebral energy dysfunction after resuscitation in a pig model of cardiac arrest (CA).</AbstractText>Thirty-four Wuzhishan miniature inbred pigs were randomly divided into three groups: the SFI group (n=12), the saline group (SA group, n=12), and the sham-operated group (sham group, n=10). Following successful return of spontaneous circulation (ROSC) from 8-min untreated ventricular fibrillation, animals received a continuous infusion of either SFI (0.2 mL/min) or saline for 6 h. Cerebral performance category score was evaluated at 24 and 48 h after ROSC, followed by positron emission tomography and computed tomography scans of cerebral glucose uptake. Surviving pigs were euthanized 48 h after ROSC, and the brains were removed for detecting mitochondrial function.</AbstractText>Compared with the SA group, SFI treatment produced a better neurologic outcome 48 h after ROSC (P<0.05). However, there was no significant difference of survival rate between the SA and SFI groups (83.3% vs. 81.8%, P>0.05). After ROSC, the SA group showed a decrease in the maximum standardized uptake value of different regions in the brain tissue, where SFI treatment can ameliorate these decreases (P<0.01 or P<0.05). Improved mitochondrial respiratory properties and higher mitochondrial membrane potential were also found following SFI treatment compared with the SA group at 48 h after ROSC (P<0.05 or P<0.01).</AbstractText>SFI treatment after resuscitation has significant neuroprotective effects against disruption of cerebral energy metabolism from CA by improving glucose uptake and by normalizing mitochondrial function.</AbstractText> |
11,267 | Massive purulent pericardial effusion presenting as atrial fibrillation with rapid rate: case report and review of the literature. | Although pericardial effusion with afib is not rare, the combination of purulent pericardial effusion presenting as afib is not a common occurrence particularly in the developing world.The more common symptoms associated with purulent pericardial effusion are fever, dyspenia, and tachycardia. Without prompt recognition followed by antibiotics and surgical drainage, tamponade, and shock can potentially lead to death.</AbstractText>A 59-year-old male was transferred to our hospital for evaluation of afib with rapid rate associated with cough and dyspenia. He reported fevers, chills, cough and sputum for 1 week. Complaints included chest pain with relief upon lying down. Patient was afebrile with a pulse of 101 and blood pressure of 119/89. WBC 39,200 cells/ml. Chest X-RAY showed right lower lobe pneumonia and EKG revealed afib, rapid ventricular response, and secondary ST changes inferolaterally. Pericardial effusion and thickened pericardium were eveident on echo. Patient was treated for community acquired pneumonia, along with heparin and IV amiodarone. Both sputum cultures and pericardiocentesis revealed S. Pneumoniae. Cardioversion reestablished sinus mechanism. Intially pericardial effusion resolved, but later reaccumulated at which point it was decided to perform a subxiphoid pericardial window. Follow up showed no effusion and patient was asymptomatic.</AbstractText>Purulent pericardial effusion with atrial fibrillation and rapid ventricular rate needs to be recognized promptly. Because friction fub and chest pain are not present in every case, prompt management in the setting of pneumonia and minor hemodynamic derangements can aid in the treatment of this potentially life threating disease.</AbstractText> |
11,268 | Regional variation in patients and outcomes in the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trial. | Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) patients with heart failure and preserved left ventricular ejection fraction assigned to spironolactone did not achieve a significant reduction in the primary composite outcome (time to cardiovascular death, aborted cardiac arrest, or hospitalization for management of heart failure) compared with patients receiving placebo. In a post hoc analysis, an ≈4-fold difference was identified in this composite event rate between the 1678 patients randomized from Russia and Georgia compared with the 1767 enrolled from the United States, Canada, Brazil, and Argentina (the Americas).</AbstractText>To better understand this regional difference in clinical outcomes, demographic characteristics of these populations and their responses to spironolactone were explored. Patients from Russia/Georgia were younger, had less atrial fibrillation and diabetes mellitus, but were more likely to have had prior myocardial infarction or a hospitalization for heart failure. Russia/Georgia patients also had lower left ventricular ejection fraction and creatinine but higher diastolic blood pressure (all P<0.001). Hyperkalemia and doubling of creatinine were more likely and hypokalemia was less likely in patients receiving spironolactone in the Americas with no significant treatment effects in Russia/Georgia. All clinical event rates were markedly lower in Russia/Georgia, and there was no detectable impact of spironolactone on any outcomes. In contrast, in the Americas, the rates of the primary outcome, cardiovascular death, and hospitalization for heart failure were significantly reduced by spironolactone.</AbstractText>This post hoc analysis demonstrated greater potassium and creatinine changes and possible clinical benefits with spironolactone in patients with heart failure and preserved ejection fraction from the Americas.</AbstractText>http://www.clinicaltrials.gov. Unique identifier: NCT00094302.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,269 | A Phase II trial of Belinostat (PXD101) in patients with relapsed or refractory peripheral or cutaneous T-cell lymphoma. | Belinostat is a pan-histone deacetylase inhibitor with antitumour and anti-angiogenic properties. An open label, multicentre study was conducted in patients with peripheral T-cell lymphoma (PTCL) or cutaneous T-cell lymphoma (CTCL) who failed ≥1 prior systemic therapy and were treated with belinostat (1000 mg/m(2) intravenously ×5 d of a 21-d cycle). The primary endpoint was objective response rate (ORR). Patients with PTCL (n = 24) had received a median of three prior systemic therapies (range 1-9) and 40% had stage IV disease. Patients with CTCL (n = 29) had received a median of one prior skin-directed therapy (range 0-4) and four prior systemic therapies (range 1-9); 55% had stage IV disease. The ORRs were 25% (PTCL) and 14% (CTCL). Treatment-related adverse events occurred in 77% of patients; nausea (43%), vomiting (21%), infusion site pain (13%) and dizziness (11%) had the highest incidence. Treatment-related serious adverse events were Grade 5 ventricular fibrillation; Grade 4 thrombocytopenia; Grade 3 peripheral oedema, apraxia, paralytic ileus and pneumonitis; and Grade 2 jugular vein thrombosis. Belinostat monotherapy was well tolerated and efficacious in patients with recurrent/refractory PTCL and CTCL. This trial was registered at www.clinicaltrials.gov as NCT00274651. |
11,270 | Right versus left atrial pacing in patients with sick sinus syndrome and paroxysmal atrial fibrillation (Riverleft study): study protocol for randomized controlled trial. | The incidence of sick sinus syndrome will increase due to population ageing. Consequently, this will result in an increase in the number of pacemaker implantations. The atrial lead is usually implanted in the right atrial appendage, but this position may be ineffective for prevention of atrial fibrillation. It has been suggested that pacing distally in the coronary sinus might be more successful in preventing atrial fibrillation episodes. The aim of this trial is to study the efficacy of distal coronary sinus versus right atrial appendage pacing in preventing atrial fibrillation episodes in patients with sick sinus syndrome.</AbstractText><AbstractText Label="METHODS/DESIGN" NlmCategory="METHODS">This study is designed as a multicenter, randomized controlled trial. Patients with sick sinus syndrome and at least one atrial fibrillation episode of 30 seconds or more in the six months before recruitment will be eligible for participation in this study.All participants will be randomized between pacing distally in the coronary sinus and right atrial appendage. Randomization is stratified for all participating centers. Conventional dual-chamber pacemakers with advanced home monitoring functionality will be implanted. The ventricular lead will be implanted in the right ventricular apex. The first three months of the 36-month follow-up period are considered as run-in time. During the pre-randomization visit and follow-up, an interview, electrocardiogram and pacemaker assessment will be performed, prescribed antiarrhythmic medication will be reviewed and patients will be asked to complete an SF-36 questionnaire. An echocardiographic examination will be conducted in the pre-randomization phase and at the end of each follow-up year. Home monitoring will be used to send daily reports in case of atrial fibrillation episodes.</AbstractText>This randomized controlled trial is the first in which home monitoring will be used to compare atrial fibrillation recurrences between pacing in the distal coronary sinus or right atrial appendage. Home monitoring gives the opportunity to accurately detect atrial fibrillation episodes and to study characteristics of atrial fibrillation episodes. Should distal coronary sinus pacing significantly diminish atrial fibrillation recurrences, this study will redefine the preferential location of an atrial lead for preventive pacing.</AbstractText>Current Controlled Trials ISRCTN65911661, registered on 8 July 2013.</AbstractText> |
11,271 | Relation of indirect vasodilator use to prognosis in patients with chronic severe mitral regurgitation. | The relation of indirect vasodilator use to cardiac events (CE) is undefined for chronic severe nonischemic mitral regurgitation (MR). The aim of this study was to resolve this knowledge deficiency.</AbstractText>Data from 52 consecutive patients in our prospective natural history study with isolated chronic severe nonischemic MR were assessed post hoc over 19 years to examine the relation of indirect vasodilator use to subsequent CE (death or indications for valve surgery). At entry, no patient had surgical indications, 14% had hypertension (HTN) and 7 chronically received vasodilators (5 angiotensin-converting enzyme inhibitor, 1 receptor blocker and 1 α-adrenergic blocker). CE differences were assessed by log-rank comparison of Kaplan-Meier curves.</AbstractText>During follow-up, CE included sudden death (1 patient), heart failure (7 patients), atrial fibrillation (6 patients), left ventricular (LV) systolic dimension >4.5 cm (12 patients), LV ejection fraction (EF) <60% (7 patients), right ventricular EF <35% (2 patients) and combination CE (7 patients). Overall, vasodilator use did not predict CE (not significant). However, patients without HTN had higher CE rates with vasodilators than without (p = 0.007), while those with HTN and vasodilators had lower CE rates than those without vasodilators (p = 0.04).</AbstractText>Vasodilator use appears to confer no survival benefit in patients with chronic severe MR. The small number of patients with HTN precludes conclusions about modulation of vasodilator effect by HTN. Randomized trials are needed to conclusively evaluate this association.</AbstractText> |
11,272 | Preoperative risk factors for residual tricuspid regurgitation after isolated left-sided valve surgery: a systematic review and meta-analysis. | Residual tricuspid regurgitation (TR) that has developed after isolated left-sided valve surgery is not uncommon. Indications for concomitant tricuspid repair at the initial operation have not been well established. The selection of high-risk preoperative patients is of great importance in this situation.</AbstractText>Six databases were searched to access eligible articles reporting potential risk factors for the development of residual TR. The pooled analysis of risk factors was based on odds ratios or mean differences with their 95% confidence intervals.</AbstractText>A total of 3,138 patients with 487 residual TR in 11 studies were analyzed. Of the 14 candidate parameters in our meta-analysis, 10 factors, i.e. older age, female gender, atrial fibrillation, rheumatic etiology, mitral valve surgery, previous valve surgery, a long time from onset to surgery, 2+/3+ TR and enlarged left and right atria, were found to be significantly associated with the development of residual TR.</AbstractText>Our study highlights the role of the above preoperative risk factors in the development of residual TR after isolated left-sided valve surgery and emphasizes the need of further studies to investigate other potential predictors. Moreover, predictive models or scoring systems for the identification of patients at a high risk for developing late TR are urgently needed.</AbstractText> |
11,273 | Origin and characteristics of high Shannon entropy at the pivot of locally stable rotors: insights from computational simulation. | Rotors are postulated to maintain cardiac fibrillation. Despite the importance of bipolar electrograms in clinical electrophysiology, few data exist on the properties of bipolar electrograms at rotor sites. The pivot of a spiral wave is characterized by relative uncertainty of wavefront propagation direction compared to the periphery. The bipolar electrograms used in electrophysiology recording encode information on both direction and timing of approaching wavefronts.</AbstractText>To test the hypothesis that bipolar electrograms from the pivot of rotors have higher Shannon entropy (ShEn) than electrograms recorded at the periphery due to the spatial dynamics of spiral waves.</AbstractText>We studied spiral wave propagation in 2-dimensional sheets constructed using a simple cell automaton (FitzHugh-Nagumo), atrial (Courtemanche-Ramirez-Nattel) and ventricular (Luo-Rudy) myocyte cell models and in a geometric model spiral wave. In each system, bipolar electrogram recordings were simulated, and Shannon entropy maps constructed as a measure of electrogram information content. ShEn was consistently highest in the pivoting region associated with the phase singularity of the spiral wave. This property was consistently preserved across; (i) variation of model system (ii) alterations in bipolar electrode spacing, (iii) alternative bipolar electrode orientation (iv) bipolar electrogram filtering and (v) in the presence of rotor meander. Directional activation plots demonstrated that the origin of high ShEn at the pivot was the directional diversity of wavefront propagation observed in this location.</AbstractText>The pivot of the rotor is consistently associated with high Shannon entropy of bipolar electrograms despite differences in action potential model, bipolar electrode spacing, signal filtering and rotor meander. Maximum ShEn is co-located with the pivot for rotors observed in the bipolar electrogram recording mode, and may be an intrinsic property of spiral wave dynamic behaviour.</AbstractText> |
11,274 | Sudden cardiac arrest associated with an anomalous aortic origin of the left coronary artery from the opposite sinus of valsalva. | A 13-year-old boy was brought to our hospital after recovering from ventricular fibrillation that occurred after an episode of chest pain during training with his soccer team. Subsequent 64-slice multidetector computed tomography revealed the left coronary artery arising from the right sinus of Valsalva, which coursed between the ascending aorta and root of the main pulmonary artery. Surgical correction including unroofing of the left coronary ostium and pulmonary artery translocation was performed successfully. One year later, he remained asymptomatic and was back on his soccer team. |
11,275 | Cardiac resynchronization therapy reduces T-wave alternans in patients with heart failure. | T-wave alternans (TWA) represents myocardial instability. The present study was to determine the impact of cardiac resynchronization therapy (CRT) on TWA and left ventricular ejection fraction (LVEF) in heart failure patients.</AbstractText>T-wave alternans was analysed using a spectral method in 27 CRT-ICD patients. Ambulatory device electrograms were collected and LVEF and New York Heart Association (NYHA) classification were assessed at baseline prior to CRT and 3 months following CRT. Patients were followed for 6 months to monitor cardiac events. Spectral TWA of device electrograms was measured during AAI and CRT pacing tests. Each pacing mode had the up-titration pacing rate from 90 to 105 b.p.m. with 90 s for each pacing rate. At baseline, 20 (76.9%) patients had TWA during AAI pacing tests and 13 (50%) during CRT pacing tests (P = 0.044 between two pacing modes). Following 3-month CRT, TWA was identified in 11 patients (45.8%) during AAI pacing tests (a 31.1% reduction from the baseline value, P = 0.023) and 7 patients (28%) during CRT pacing tests (a 22% reduction, P = 0.108). Six of seven patients who had cardiac events had TWA (three patients had arrhythmic events, two died of heart failure, one received heart transplant). Overall, LVEF improved from 27.3 ± 5.8 to 35.9 ± 10.5% (P < 0.001) and NYHA classification improved from 2.8 ± 0.6 to 1.6 ± 0.6 after 3-month CRT (P < 0.001).</AbstractText>In heart failure patients who receive a CRT-ICD, CRT reduces TWA that is associated to cardiac events, suggesting that CRT promotes clinically significant reverse electrical and mechanical remodelling.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
11,276 | Gap junction remodelling by chronic pressure overload is related to the increased susceptibility to atrial fibrillation in rat heart. | Left atrial (LA) fibrosis caused by various pathological stimuli is a common finding. However, the difference of atrial remodelling via haemodynamic change in diverse cardiomyopathy has not been elucidated.</AbstractText>Male Sprague-Dawley rats (6-8 weeks, n = 180) were randomly assigned to three groups and corresponding sham control groups: (i) ischaemic cardiomyopathy, (ii) left ventricular hypertrophy (LVH), and (iii) dilated cardiomyopathy. At 12 weeks after operation, atrial fibrillation (AF) inducibility and duration were assessed by in vivo burst transoesophageal pacing. Using the Langendorff apparatus, left ventricular (LV) function and pressure were measured. The expression of connexin-43 (Cx43) and alpha-smooth muscle actin (α-SMA) in atrial tissues was assessed by quantitative real-time polymerase chain reaction and immunohistochemical staining. Fibrosis was analysed by Masson's trichrome staining. Compared with controls, the LA weight/heart weight ratio was increased in the LVH group alone, and was significantly correlated with AF duration (P < 0.001, R = 0.388). Atrial fibrillation inducibility and duration were higher and longer only in the LVH group (P = 0.002, 0.079, respectively), and isolated LV diastolic dysfunction and elevated LV pressure were observed. Although α-SMA expression and fibrosis were increased in all three cardiomyopathy models, down-regulation of Cx43 expression in the LA was observed in the LVH group alone.</AbstractText>Chronic pressure overload in the absence of LV systolic dysfunction resulted in LA hypertrophy and increased susceptibility to AF, which might be related to conduction abnormality via decreased expression and lateral distribution of Cx43 as well as interstitial fibrosis.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
11,277 | Assessment of atrial fibrillation and vulnerability in patients with Wolff-Parkinson-White syndrome using two-dimensional speckle tracking echocardiography. | The aim was to assess atrial fibrillation (AF) and vulnerability in Wolff-Parkinson-White (WPW) syndrome patients using two-dimensional speckle tracking echocardiography (2D-STE).</AbstractText>All patients were examined via transthoracic echocardiography and 2D-STE in order to assess atrial function 7 days before and 10 days after RF catheter ablation. A postoperative 3-month follow-up was performed via outpatient visit or telephone calls.</AbstractText>Results showed significant differences in both body mass index (BMI) and supraventricular tachycardia (SVT) duration between WPW patients and DAVNP patients (both P<0.05). Echocardiography revealed that the maximum left atrial volume (LAVmax) and the left ventricular mass index (LVMI) in diastole increased noticeably in patients with WPW compared to patients with DAVNP both before and after ablation (all P<0.05). Before ablation, there were obvious differences in the levels of SRs, SRe, and SRa from the 4-chamber view (LA) in the WPW patients group compared with patients in the DAVNP group (all P<0.05). In the AF group, there were significant differences in the levels of systolic strain rate (SRs), early diastolic strain rate (SRe), and late diastolic strain rate (SRa) from the 4-chamber view (LA) both before and after ablation (all P<0.05). In the non-AF group, there were decreased SRe levels from the 4-chamber view (LA/RA) pre-ablation compared to post-ablation (all P<0.05).</AbstractText>Our findings provide convincing evidence that WPW syndrome may result in increased atrial vulnerability and contribute to the development of AF. Further, RF catheter ablation of AAV pathway can potentially improve atrial function in WPW syndrome patients. Two-dimensional speckle tracking echocardiography imaging in WPW patients would be necessary in the evaluation and improvement of the overall function of RF catheter ablation in a long-term follow-up period.</AbstractText> |
11,278 | Automatic quantitative analysis of t-tubule organization in cardiac myocytes using ImageJ. | The transverse tubule system in mammalian striated muscle is highly organized and contributes to optimal and homogeneous contraction. Diverse pathologies such as heart failure and atrial fibrillation include disorganization of t-tubules and contractile dysfunction. Few tools are available for the quantification of the organization of the t-tubule system. We developed a plugin for the ImageJ/Fiji image analysis platform developed by the National Institutes of Health. This plugin (TTorg) analyzes raw confocal microscopy images. Analysis options include the whole image, specific regions of the image (cropping), and z-axis analysis of the same image. Batch analysis of a series of images with identical criteria is also one of the options. There is no need to either reorientate any specimen to the horizontal or to do a thresholding of the image to perform analysis. TTorg includes a synthetic "myocyte-like" image generator to test the plugin's efficiency in the user's own experimental conditions. This plugin was validated on synthetic images for different simulated cell characteristics and acquisition parameters. TTorg was able to detect significant differences between the organization of the t-tubule systems in experimental data of mouse ventricular myocytes isolated from wild-type and dystrophin-deficient mice. TTorg is freely distributed, and its source code is available. It provides a reliable, easy-to-use, automatic, and unbiased measurement of t-tubule organization in a wide variety of experimental conditions. |
11,279 | Unusual Case of a Free-floating Ball Thrombus with Preserved Attachment to the Left Atrial Appendage Causing Recurrent Obstruction of the Left Ventricular Outflow Tract. | Few cases of a left atrial thrombus without mitral valve disease have been reported. We present an unusual case in which a patient presented to the emergency department with syncope and acute cerebral ischemia caused by a ball thrombus originating from the left atrium (LA). An emergency bedside echocardiogram showed the LA ball thrombus intermittently obstructing the mitral orifice and, at times, compromising the left ventricular outflow tract. This thrombus was determined to be the source of cerebral embolization resulting in acute ischemia. Surgical excision of the mass was performed. At operation, the thrombus was found to be tethered to the left atrial appendage. This tethering was not apparent on the echocardiographic images, where the thrombus appeared to be free floating. This case demonstrates the utility of transthoracic echocardiography in establishing the etiology of emergent conditions seemingly unrelated to acute cardiac disease, in this situation a neurologic presentation with syncope and cerebral ischemia. |
11,280 | Ventricular fibrillation induction and diffuse abnormal ST-segment response to ajmaline in a patient with apparent pre-existing dynamic right bundle branch block. | ST-segment elevation in the right precordial electrocardiography (ECG) leads in Brugada syndrome (BS) can be unmasked by class I anti-arrhythmic drugs (sodium channel blockers) administration. It is still debated whether this ECG pattern is better explained by abnormal repolarization or ventricular conduction and depolarization. Conduction diseases can conceal type 1 BS-like ECG in standard V1-V3 leads. ECG alterations were found also in alternative leads. The role of electrophysiology study (EPS) in sudden cardiac death risk stratification remains controversial, and could depend on the phenotypic expression of the cardiac sodium channels disease.</AbstractText>We describe unmasked diffuse J-point and ST-segment anomalies in peripheral and precordial ECG leads and ventricular fibrillation (VF) induction by EPS after ajmaline administration in a patient with pre-existing atypical right bundle branch block (RBBB) concealing subtle anomalies in standard V1-V3 leads. RBBB was influenced by the underlying BS-like ECG associating repolarization anomaly and pre-existing conduction disease. EPS induced VF when RBBB was associated with BS-like ECG, and failed to induce VF when RBBB was present alone.</AbstractText>BS phenotype heterogeneity requires further studies to improve the knowledge of its pathophysiological mechanisms associated with conduction diseases in order to better identify an individual therapy and prognostic stratification.</AbstractText> |
11,281 | Right ventricular function in heart failure with preserved ejection fraction: a community-based study. | The prevalence and clinical significance of right ventricular (RV) systolic dysfunction (RVD) in patients with heart failure and preserved ejection fraction (HFpEF) are not well characterized.</AbstractText>Consecutive, prospectively identified HFpEF (Framingham HF criteria, ejection fraction ≥50%) patients (n=562) from Olmsted County, Minnesota, underwent echocardiography at HF diagnosis and follow-up for cause-specific mortality and HF hospitalization. RV function was categorized by tertiles of tricuspid annular plane systolic excursion and by semiquantitative (normal, mild RVD, or moderate to severe RVD) 2-dimensional assessment. Whether RVD was defined by semiquantitative assessment or tricuspid annular plane systolic excursion ≤15 mm, HFpEF patients with RVD were more likely to have atrial fibrillation, pacemakers, and chronic diuretic therapy. At echocardiography, patients with RVD had slightly lower left ventricular ejection fraction, worse diastolic dysfunction, lower blood pressure and cardiac output, higher pulmonary artery systolic pressure, and more severe RV enlargement and tricuspid valve regurgitation. After adjustment for age, sex, pulmonary artery systolic pressure, and comorbidities, the presence of any RVD by semiquantitative assessment was associated with higher all-cause (hazard ratio=1.35; 95% confidence interval, 1.03-1.77; P=0.03) and cardiovascular (hazard ratio=1.85; 95% confidence interval, 1.20-2.80; P=0.006) mortality and higher first (hazard ratio=1.99; 95% confidence interval, 1.35-2.90; P=0.0006) and multiple (hazard ratio=1.81; 95% confidence interval, 1.18-2.78; P=0.007) HF hospitalization rates. RVD defined by tricuspid annular plane systolic excursion values showed similar but weaker associations with mortality and HF hospitalizations.</AbstractText>In the community, RVD is common in HFpEF patients, is associated with clinical and echocardiographic evidence of more advanced HF, and is predictive of poorer outcomes.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,282 | [Patent venous graft for the left anterior descending branch 25 years after surgery; report of a case]. | We report a case of a patent venous graft for the left anterior descending branch 25 years after surgery. In 1986 at the age of 59 years, the patient underwent coronary artery bypass grafting( CABG) to the left anterior descending(LAD)artery using a saphenous vein graft (SVG). In 2011, twenty-five years after the surgery, the patient experienced a chest pain and was hospitalized. Due to a strong chest pain and pulmonary edema, emergency coronary angiography was performed under tracheal intubation. The SVG was patent, but severe stenosis was found proximal to the middle of the graft. Although percutaneous coronary intervention with a bare-metal stent was performed, the patient died of ventricular fibrillation on the 38th postoperative day. The use of arterial grafts for CABG is currently predominant, but SVG should still be considered a reliable alternative. |
11,283 | Predictors of high defibrillation threshold in patients with implantable cardioverter-defibillator using a transvenous dual-coil lead. | Defibrillation testing (DT) is considered a standard procedure during implantable cardioverter-defibrillator (ICD) implantation. However, little is known about the factors that are significantly related to patients with high defibrillation threshold (DFT) using the present triad system.</AbstractText>We examined 286 consecutive patients who underwent ICD implantation with a transvenous dual-coil lead and DT from December 2000 to December 2011. We defined patients who required 25 J or more by the implanted device as the high DFT group, and those who required less than 25 J as the normal DFT group. For each patient, assessment parameters included underlying disease, comorbidities, NYHA functional class, drugs, and echocardiographic measures. The high DFT group consisted of 12 patients (4.2%). Multivariate analysis identified 3 independent predictors for high DFT: atrial fibrillation (odds ratio (OR) 4.85, 95% confidence interval (CI) 1.24-22.33, P=0.023), hypertension (OR 4.01, 95% CI 1.08-15.96, P=0.039), thickness of interventricular septum (IVS) >12 mm (OR 4.82, 95% CI 1.17-20.31, P=0.030).</AbstractText>Atrial fibrillation, hypertension and IVS hypertrophy were significantly associated with high DFT. Identification of such patients could help to lower the risk of complications with DT.</AbstractText> |
11,284 | Optimising pharmacotherapy for secondary prevention of non-invasively managed acute coronary syndrome. | About half of all patients who experience an acute coronary syndrome (ACS) in Australia have their conditions managed non-invasively - that is, they do not undergo coronary angiography and revascularisation in hospital. ACS patients whose conditions are managed non-invasively may not receive the same level of evidence-based care as those who receive coronary revascularisation. This article reviews the optimal pharmacological management of ACS managed non-invasively. There is strong evidence to support the prescription of dual antiplatelet therapy (DAPT; aspirin with a P2Y12 inhibitor). DAPT should continue for 12 months after an ACS, then aspirin should be continued indefinitely. Anticoagulation with warfarin or a novel oral anticoagulant may be needed if atrial fibrillation occurs; the combination with DAPT increases the risk of bleeding. Unless contraindicated, high-intensity statin therapy should be prescribed for all post-ACS patients irrespective of their cholesterol level. Non-statin lipid therapy has not been shown to improve outcomes. Use of β-adrenergic blockers is recommended in most guidelines, but the clinical trials to support this recommendation were performed more than 30 years ago, and routine long-term use may not be relevant to modern treatment, except when there is cardiac failure or left ventricular dysfunction. Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers are also widely recommended, but the evidence for benefit is stronger when there is left ventricular dysfunction. Calcium-channel blockers, nitrates, antiarrhythmic drugs, digoxin and diuretics do not improve outcomes in post-ACS patients. |
11,285 | A practical guide to early repolarization. | Early repolarization has been associated in the past decade with idiopathic ventricular fibrillation and arrhythmic death. The purpose of this review is to clarify recent changes in the definition of early repolarization and provide a practical approach to patients with this electrocardiographic sign.</AbstractText>Recent population studies have associated early repolarization with arrhythmic death. Challenges remain, however, in interpreting the risk of the early repolarization electrocardiographic pattern, as it is a common finding in the general population with a prevalence of 3-13%. Early repolarization characteristics associated with an especially high risk include high-amplitude J-point elevation, horizontal/descending ST segment, and inferior lead location.In view of the association of early repolarization with sudden death, a syndrome termed 'early repolarization syndrome' (ERS) has been accepted as the latest 'channelopathy' in patients with cardiac arrest, pronounced early repolarization pattern, and an otherwise structurally normal heart.The physiological basis of early repolarization is thought to involve an electrical transmural gradient produced by the transient outward current. Recent genetic studies have associated mutations in genes contributing to this current and other ion channels with ERS, although definitive genetic data do not yet exist to confirm pathogenicity.</AbstractText>ERS patients are rare and have a high risk of recurrent cardiac events. ICD implantation and possibly quinidine are the recommended treatments in this group. Opposingly, asymptomatic individuals with early repolarization are very common and, as a group, have a good prognosis. Sudden death preventive measures in these asymptomatic patients are limited to rare and unique cases.</AbstractText> |
11,286 | Contact force-sensing catheters. | The purpose of this review is to highlight recent research findings in contact force-sensing radiofrequency ablation catheters.</AbstractText>Contact force parameters evaluated during pulmonary vein isolation for treating atrial fibrillation correlated well with the presence of gaps in the wide area circumferential ablation lines at 3 months, decreased procedural times, and improved clinical outcome at 1 year. The contact force during pulmonary vein isolation should be a target of 10-20 g of force and a minimum force-time integral of 400 g/s for each new lesion. In the ventricle, contact force varied depending on whether a transseptal versus retrograde aortic approach was utilized: contact force use yielded more visible ablation lesions at necropsy.</AbstractText>Contact force-sensing catheters have demonstrated improved outcome after catheter ablation of atrial fibrillation. Future studies will focus on ventricular tachycardia ablation; preliminary data suggest more durable lesions with contact force-sensing catheters. Contact force catheters may enhance academic training by giving real-time feedback regarding catheter contact, increase safety, and may lead to a resurgence in remote navigation ablation systems.</AbstractText> |
11,287 | Beating heart myocardial revascularisation of a sudden cardiac death survivor with spontaneous coronary artery dissection: pitfalls from diagnosis to surgery. | Spontaneous coronary artery dissection is a rare clinical condition with a wide range of clinical presentations ranging from asymptomatic cases to life-threatening ventricular arrhythmias and sudden cardiac death. The exact pathophysiological mechanism has not been fully established yet. We would like to present a survivor of sudden cardiac death presenting with ventricular fibrillation due to spontaneous coronary artery dissection. The prompt evaluation, medical management, surgical myocardial revascularisation and value of off-pump coronary artery bypass surgery are discussed. |
11,288 | Sudden death of a horse with supraventricular tachycardia following oral administration of flecainide acetate. | To describe a case of supraventricular tachycardia and sudden death in a horse following administration of flecainide acetate.</AbstractText>An 8-year-old Hanoverian warmblood gelding was treated for chronic, naturally occurring, supraventricular tachycardia with digoxin, procainamide hydrochloride, quinidine sulfate, and flecainide acetate. After oral administration of flecainide, polymorphic ventricular tachycardia (torsades de pointes) and ventricular fibrillation developed, leading to cardiovascular collapse and death.</AbstractText>Atrial fibrillation is the most commonly diagnosed dysrhythmia associated with poor performance in horses, while atrial tachycardia is rarely documented. Here, we describe a case of sudden death in a horse with atrial tachycardia following the oral administration of flecainide acetate, after the lack of response to other antiarrhythmic drugs. Information provided in this case report is new and will make clinicians aware of the potential complications of flecainide alone or in combination with other drugs, in horses with cardiac dysrhythmias.</AbstractText>© Veterinary Emergency and Critical Care Society 2014.</CopyrightInformation> |
11,289 | Clinical impact of a new left bundle branch block following TAVI implantation: 1-year results of the TAVIK cohort. | Compared with surgical aortic valve replacement, transcatheter aortic valve implantation (TAVI) is associated with a higher risk of developing a new conduction disorder that necessitates permanent pacemaker implantation (PM). The most frequently observed conduction disorder is left bundle branch block (LBBB), which impairs left ventricular function.</AbstractText>The primary objective of this study was to assess the incidence and prognostic significance of persistent new-onset LBBB following TAVI. Factors predictive of persistent new-onset LBBB were also explored.</AbstractText>This study included a total of 793 patients who underwent TAVI between May 2008 and April 2012. Patients were divided into two groups: those with persistent new-onset LBBB and those without persistent new-onset LBBB. Follow-up was conducted within 1-year of TAVI.</AbstractText>Persistent new-onset LBBB was observed in 31.1 % (n = 197) out of 634 eligible patients. At 30 days and 1-year post-TAVI, the all-cause mortality rate was higher in patients with persistent new-onset LBBB (6.1 %, n = 12 and 20.8 %, n = 41, respectively) than in patients without new-onset LBBB (3.3 %, n = 10 and 13.0 %, n = 57, respectively; p = 0.014 and p = 0.010 for the two time points). Multivariate regression analyses revealed, that persistent new-onset LBBB was an independent predictor of all-cause mortality at 1 year (HR 1.84, 95 %CI 1.35-2.02). PM implantation was observed slightly more frequently in patients with persistent new-onset LBBB (14.2 %) than in those without (9.4 %; HR 1.60, 95 %CI 0.96-2.67). Risk factors for pacemaker (PM) were baseline RBBB (HR 6.23, 95 %CI 3.76-10.33), chronic atrial fibrillation (HR 1.75, 95 %CI 1.10-2.56) and the Medtronic CoreValve implantation (HR 2.40, 95 %CI 1.55-3.75). At 1-year follow-up, the mean survival of patients with PM (81.2 %) was slightly lower, but not significantly different from that of patients without PM (85.0 %; p = 0.377). Upon multivariable logistic binary regression analysis Medtronic CoreValve was associated with an increase rate of persistent new-onset LBBB (HR 2.52, 95 %CI 1.67-3.80) and PM implantation. Mortality during 1 year of follow-up, however, was neither increased in the total population (p = 0.232), nor in a subgroup of those with LBBB in a comparison of Medtronic CoreValve and Edwards SAPIEN.</AbstractText>This study demonstrated that persistent new-onset LBBB was associated with increased mortality in patients undergoing TAVI. Compared with the Edwards SAPIEN valve, implantation of the Medtronic CoreValve resulted in a higher rate of both persistent new-onset LBBB and PM but not death.</AbstractText> |
11,290 | Grading and interpretation of white matter hyperintensities using statistical maps. | We aimed to generate rigorous graphical and statistical reference data based on volumetric measurements for assessing the relative severity of white matter hyperintensities (WMHs) in patients with stroke.</AbstractText>We prospectively mapped WMHs from 2699 patients with first-ever ischemic stroke (mean age=66.8±13.0 years) enrolled consecutively from 11 nationwide stroke centers, from patient (fluid-attenuated-inversion-recovery) MRIs onto a standard brain template set. Using multivariable analyses, we assessed the impact of major (age/hypertension) and minor risk factors on WMH variability.</AbstractText>We have produced a large reference data library showing the location and quantity of WMHs as topographical frequency-volume maps. This easy-to-use graphical reference data set allows the quantitative estimation of the severity of WMH as a percentile rank score. For all patients (median age=69 years), multivariable analysis showed that age, hypertension, atrial fibrillation, and left ventricular hypertrophy were independently associated with increasing WMH (0-9.4%, median=0.6%, of the measured brain volume). For younger (≤69) hypertensives (n=819), age and left ventricular hypertrophy were positively associated with WMH. For older (≥70) hypertensives (n=944), age and cholesterol had positive relationships with WMH, whereas diabetes mellitus, hyperlipidemia, and atrial fibrillation had negative relationships with WMH. For younger nonhypertensives (n=578), age and diabetes mellitus were positively related to WMH. For older nonhypertensives (n=328), only age was positively associated with WMH.</AbstractText>We have generated a novel graphical WMH grading (Kim statistical WMH scoring) system, correlated to risk factors and adjusted for age/hypertension. Further studies are required to confirm whether the combined data set allows grading of WMH burden in individual patients and a tailored patient-specific interpretation in ischemic stroke-related clinical practice.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,291 | Atrial fibrillation ablation in systolic dysfunction: clinical and echocardiographic outcomes. | Heart failure and atrial fibrillation (AF) often coexist in a deleterious cycle.</AbstractText>To evaluate the clinical and echocardiographic outcomes of patients with ventricular systolic dysfunction and AF treated with radiofrequency (RF) ablation.</AbstractText>Patients with ventricular systolic dysfunction [ejection fraction (EF) <50%] and AF refractory to drug therapy underwent stepwise RF ablation in the same session with pulmonary vein isolation, ablation of AF nests and of residual atrial tachycardia, named "background tachycardia". Clinical (NYHA functional class) and echocardiographic (EF, left atrial diameter) data were compared (McNemar test and t test) before and after ablation.</AbstractText>31 patients (6 women, 25 men), aged 37 to 77 years (mean, 59.8 ± 10.6), underwent RF ablation. The etiology was mainly idiopathic (19 p, 61%). During a mean follow-up of 20.3 ± 17 months, 24 patients (77%) were in sinus rhythm, 11 (35%) being on amiodarone. Eight patients (26%) underwent more than one procedure (6 underwent 2 procedures, and 2 underwent 3 procedures). Significant NYHA functional class improvement was observed (pre-ablation: 2.23 ± 0.56; postablation: 1.13 ± 0.35; p < 0.0001). The echocardiographic outcome also showed significant ventricular function improvement (EF pre: 44.68% ± 6.02%, post: 59% ± 13.2%, p = 0.0005) and a significant left atrial diameter reduction (pre: 46.61 ± 7.3 mm; post: 43.59 ± 6.6 mm; p = 0.026). No major complications occurred.</AbstractText>Our findings suggest that AF ablation in patients with ventricular systolic dysfunction is a safe and highly effective procedure. Arrhythmia control has a great impact on ventricular function recovery and functional class improvement.</AbstractText> |
11,292 | Alternating membrane potential/calcium interplay underlies repetitive focal activity in a genetic model of calcium-dependent atrial arrhythmias. | Atrial fibrillation is often initiated and perpetuated by abnormal electrical pulses repetitively originating from regions outside the heart's natural pacemaker. In this study we examined the causal role of abnormal calcium releases from the sarcoplasmic reticulum in producing repetitive electrical discharges in atrial cells and tissues. Calsequestrin2 is a protein that stabilizes the closed state of calcium release channels, i.e. the ryanodine receptors. In the atria from mice predisposed to abnormal calcium releases secondary to the absence of calsequestrin2, we observed abnormal repetitive electrical discharges that may lead to atrial fibrillation. Here, we report a novel pathological rhythm generator. Specifically, abnormal calcium release leads to electrical activation, which in turn results in another abnormal calcium release. This process repeats itself and thus sustains the repetitive electrical discharges. These results suggest that improving the stability of ryanodine receptors might be useful to treat atrial fibrillation.</AbstractText>Aberrant diastolic calcium (Ca) release due to leaky ryanodine receptors (RyR2s) has been recently associated with atrial fibrillation (AF) and catecholaminergic polymorphic ventricular tachycardia (CPVT). However, it remains unclear how diastolic Ca release contributes to the rising of rapid repetitive focal activity, which is considered as a common AF triggering mechanism. To address this question, we conducted simultaneous voltage/Ca optical mapping in atrial tissue and one-/two-dimensional confocal imaging in atrial tissue and myocytes from wild-type (WT, n = 15) and CPVT mice lacking calsequestrin 2 (Casq2(-/-), n = 45), which promotes diastolic Ca release. During β-adrenergic stimulation (100 nM isoproterenol), only Casq2(-/-) atrial myocytes showed pacing-induced self-sustained repetitive activity (31 ± 21 s vs. none in WT). Importantly, in atrial tissue, this repetitive activity could translate to Ca-dependent focal arrhythmia. Ectopic action potential (AP) firing during repetitive activity occurred only when diastolic Ca release achieved a sufficient level of synchronization. The AP, in turn, synchronized subsequent diastolic Ca release by temporally aligning multiple sources of Ca waves both within individual myocytes and throughout the atrial tissue. This alternating interplay between AP and diastolic Ca release perpetuates the self-sustaining repetitive activity. In fact, pharmacological disruption of synchronized diastolic Ca release (by ryanodine) prevented aberrant APs; and vice versa, the inhibition of AP (by TTX or 0 Na, 0 Ca solution) de-synchronized diastolic Ca release. Taken together, these results suggest that a cyclical interaction between synchronized diastolic Ca release and AP forms a pathological rhythm generator that is involved in Ca-dependent atrial arrhythmias in CPVT.</AbstractText>© 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.</CopyrightInformation> |
11,293 | The clinical challenge of preventing sudden cardiac death immediately after acute ST-elevation myocardial infarction. | Unfortunately, of all patients experiencing acute myocardial infarction (MI), usually in the form of ST-elevation MI, 25-35% will die of sudden cardiac death (SCD) before receiving medical attention, most often from ventricular fibrillation. For patients who reach the hospital, prognosis is considerably better and has improved over the years. Reperfusion therapy, best attained with primary percutaneous coronary intervention compared to thrombolysis, has made a big difference in reducing the risk of SCD early and late after ST-elevation MI. In-hospital SCD due to ventricular tachyarrhythmias is manageable, with either preventive measures or drugs or electrical cardioversion. There is general agreement for secondary prevention of SCD post-MI with implantation of a cardioverter defibrillator (ICD) when malignant ventricular arrhythmias occur late (>48 h) after an MI, and are not due to reversible or correctable causes. The major challenge remains that of primary prevention, that is, how to prevent SCD during the first 1-3 months after ST-elevation MI for patients who have low left ventricular ejection fraction and are not candidates for an ICD according to current guidelines, due to the results of two studies, which did not show any benefits of early (<40 days after an MI) ICD implantation. Two recent documents may provide direction as to how to bridge the gap for this early post-MI period. Both recommend an electrophysiology study to guide implantation of an ICD, at least for those developing syncope or non-sustained ventricular tachycardia, who have an inducible sustained ventricular tachycardia at the electrophysiology study. An ICD is also recommended for patients with indication for a permanent pacemaker due to bradyarrhythmias, who also meet primary prevention criteria for SCD. |
11,294 | Abciximab-induced alveolar hemorrhage treated with rescue extracorporeal membranous oxygenation. | We describe a case of a 75-year-old woman presenting emergently with an anterior S-T elevation myocardial infarction that deteriorated into ventricular fibrillation requiring prompt resuscitation, resulting in cardiogenic shock. Emergency primary percutaneous coronary intervention of the left anterior descending coronary artery with adjunctive abciximab and heparin resulted in adequate coronary flow, and intra-aortic balloon pump was used to support hemodynamics. Within one hour of intervention, she developed acute respiratory distress with four-quadrant opacification of lung fields, difficulty with oxygenation, and hypotension. Emergency bronchoscopy revealed diffuse erythematous proximal airways with bloody secretions bilaterally confirming diffuse alveolar hemorrhage. An emergency veno-arterial extracorporeal membranous oxygenation (ECMO) circuit was placed at the bedside, acutely improving oxygenation and hemodynamics. She survived the hospitalization with multiple complications related to access site and prolonged intensive care unit stay, was discharged to acute rehabilitation. She is currently thriving 18 months post-procedure. This case highlights the use of ECMO in the often-fatal condition of diffuse alveolar hemorrhage related to glycoprotein inhibitor use. |
11,295 | Fragmented QRS predicts heart failure progression in patients with hypertrophic cardiomyopathy. | Although fragmented QRS complex (frag-QRS) reflecting intra-ventricular conduction delay has been shown to be a prognostic marker for cardiac events, few data exist regarding the impact of frag-QRS on cardiac events in hypertrophic cardiomyopathy (HCM).</AbstractText>Ninety-four HCM patients (56 male; mean age, 58 ± 17 years) were retrospectively investigated. Frag-QRS was defined as the presence of various RsR' patterns in at least 2 contiguous ECG leads. Major arrhythmic events (MAE) were defined as sudden cardiac death, and combined sustained ventricular tachycardia/ventricular fibrillation. New-onset atrial fibrillation (AF) was diagnosed based on ECG during provisional or routine medical examination. Heart failure (HF) with hospitalization was defined as hospital admission due to subjective or objective symptoms. Frag-QRS was detected in 31 patients (33%).TNNI3 was the most frequent disease-causing gene. Median follow-up was 4.6 years. The 4-year cumulative survival rates of cardiac death, MAE, new-onset AF and HF with hospitalization were 97.6%, 94.6%, 87.5% and 89.3%, respectively. On multivariate analysis, frag-QRS was significantly associated with HF with hospitalization (adjusted hazard ratios [95% confidence intervals]: 5.4 [1.2-36], P=0.03). Moreover, HF-free survival was significantly lower in the frag-QRS (+) group compared to the frag-QRS (-) group (79.0% vs. 95.1%, P=0.03).</AbstractText>Frag-QRS is associated with HF with hospitalization in HCM patients who had a unique distribution of gene mutations.</AbstractText> |
11,296 | Relationship between catheter contact force and radiofrequency lesion size and incidence of steam pop in the beating canine heart: electrogram amplitude, impedance, and electrode temperature are poor predictors of electrode-tissue contact force and lesion size. | Electrode-tissue contact force (CF) is believed to be a major factor in radiofrequency lesion size. The purpose of this study was to determine, in the beating canine heart, the relationship between CF and radiofrequency lesion size and the accuracy of predicting CF and lesion size by measuring electrogram amplitude, impedance, and electrode temperature.</AbstractText>Eight dogs were studied closed chest. Using a 7F catheter with a 3.5 mm irrigated electrode and CF sensor (TactiCath, St. Jude Medical), radiofrequency applications were delivered to 3 separate sites in the right ventricle (30 W, 60 seconds, 17 mL/min irrigation) and 3 sites in the left ventricle (40 W, 60 seconds, 30 mL/min irrigation) at (1) low CF (median 8 g); (2) moderate CF (median 21 g); and (3) high CF (median 60 g). Dogs were euthanized and lesion size was measured. At constant radiofrequency and time, lesion size increased significantly with increasing CF (P<0.01). The incidence of a steam pop increased with both increasing CF and higher power. Peak electrode temperature correlated poorly with lesion size. The decrease in impedance during the radiofrequency application correlated well with lesion size for lesions in the left ventricle but less well for lesions in the right ventricle. There was a poor relationship between CF and the amplitude of the bipolar or unipolar ventricular electrogram, unipolar injury current, and impedance.</AbstractText>Radiofrequencylesion size and the incidence of steam pop increase strikingly with increasing CF. Electrogram parameters and initial impedance are poor predictors of CF for radiofrequency ablation.</AbstractText>© 2014 American Heart Association, Inc.</CopyrightInformation> |
11,297 | Three-dimensional computer model of the right atrium including the sinoatrial and atrioventricular nodes predicts classical nodal behaviours. | The aim of the study was to develop a three-dimensional (3D) anatomically-detailed model of the rabbit right atrium containing the sinoatrial and atrioventricular nodes to study the electrophysiology of the nodes. A model was generated based on 3D images of a rabbit heart (atria and part of ventricles), obtained using high-resolution magnetic resonance imaging. Segmentation was carried out semi-manually. A 3D right atrium array model (∼3.16 million elements), including eighteen objects, was constructed. For description of cellular electrophysiology, the Rogers-modified FitzHugh-Nagumo model was further modified to allow control of the major characteristics of the action potential with relatively low computational resource requirements. Model parameters were chosen to simulate the action potentials in the sinoatrial node, atrial muscle, inferior nodal extension and penetrating bundle. The block zone was simulated as passive tissue. The sinoatrial node, crista terminalis, main branch and roof bundle were considered as anisotropic. We have simulated normal and abnormal electrophysiology of the two nodes. In accordance with experimental findings: (i) during sinus rhythm, conduction occurs down the interatrial septum and into the atrioventricular node via the fast pathway (conduction down the crista terminalis and into the atrioventricular node via the slow pathway is slower); (ii) during atrial fibrillation, the sinoatrial node is protected from overdrive by its long refractory period; and (iii) during atrial fibrillation, the atrioventricular node reduces the frequency of action potentials reaching the ventricles. The model is able to simulate ventricular echo beats. In summary, a 3D anatomical model of the right atrium containing the cardiac conduction system is able to simulate a wide range of classical nodal behaviours. |
11,298 | Peripheral amiodarone-related phlebitis: an institutional nursing guideline to reduce patient harm. | Intravenous amiodarone is one of the most widely used antiarrythmics for the treatment of atrial fibrillation with rapid ventricular response. Peripheral amiodarone infusion, however, often causes pain during infusion and subsequent phlebitis.Data collection on a cardiac telemetry unit revealed a high rate of phlebitis. A multidisciplinary team developed and implemented amiodarone peripheral infusion guidelines. The pre-guideline phlebitis rate was 85% and post-guideline rate was 38%, representing a 47% change or improvement. An additional finding was that the severity of phlebitis was reduced, as well. The results of this study suggest that the implementation of a peripheral amiodarone infusion guideline reduced the incidence and severity of amiodarone-related phlebitis in the cardiac population. |
11,299 | Effect of global cardiac ischemia on human ventricular fibrillation: insights from a multi-scale mechanistic model of the human heart. | Acute regional ischemia in the heart can lead to cardiac arrhythmias such as ventricular fibrillation (VF), which in turn compromise cardiac output and result in secondary global cardiac ischemia. The secondary ischemia may influence the underlying arrhythmia mechanism. A recent clinical study documents the effect of global cardiac ischaemia on the mechanisms of VF. During 150 seconds of global ischemia the dominant frequency of activation decreased, while after reperfusion it increased rapidly. At the same time the complexity of epicardial excitation, measured as the number of epicardical phase singularity points, remained approximately constant during ischemia. Here we perform numerical studies based on these clinical data and propose explanations for the observed dynamics of the period and complexity of activation patterns. In particular, we study the effects on ischemia in pseudo-1D and 2D cardiac tissue models as well as in an anatomically accurate model of human heart ventricles. We demonstrate that the fall of dominant frequency in VF during secondary ischemia can be explained by an increase in extracellular potassium, while the increase during reperfusion is consistent with washout of potassium and continued activation of the ATP-dependent potassium channels. We also suggest that memory effects are responsible for the observed complexity dynamics. In addition, we present unpublished clinical results of individual patient recordings and propose a way of estimating extracellular potassium and activation of ATP-dependent potassium channels from these measurements. |
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