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7,900 | Pause dependent ventricular tachycardia resultant from carotid sinus massage. | In this report we describe a case of atrial flutter degenerating into ventricular fibrillation after carotid sinus pressure. Carotid sinus massage is an extremely valuable and widely used diagnostic and therapeutic modality. Although generally considered a rather benign maneuver, it is not without potential risk. |
7,901 | The electrical substrate of vagal atrial fibrillation as assessed by the signal-averaged electrocardiogram of the P wave. | The autonomic nervous system is thought to be involved in the initiation of atrial fibrillation (AF). However, there is a distinct entity of vagal AF characterized by episodes occurring at rest, postprandially, or during sleep. The purpose of this study was to compare intraatrial conduction in patients with vagally mediated AF to those with nonvagal AF, using the signal-averaged electrocardiogram (SAECG) of P wave.</AbstractText>SAECG of P wave was performed in 58 patients with AF using the Marquette Medical System, and the mean filtered P-wave duration (SAPW) was measured. Nine patients were categorized as having pure vagal AF (Group I), and 42 patients as having nonvagal AF (Group II); the remaining seven patients were excluded from analysis because of incomplete data.</AbstractText>The patients in Group I were significantly younger and more likely to have paroxysmal lone AF, as compared to those in Group II. There was no significant difference in left atrial size and left ventricular function in the two groups. The mean SAPW was significantly shorter in Group I when compared to Group II (118 +/- 5 ms vs 149 +/- 39 ms, P < 0.001). Whereas all patients in Group I had a normal SAPW, 79% of patients in Group II had an abnormal SAPW (P < 0.001). A normal SAPW was significantly predictive of vagal AF independent of other co-variables.</AbstractText>(1) Patients with vagal AF are younger, and invariably have paroxysmal lone AF. (2) SAPW is normal and significantly shorter in vagal AF when compared to patients with nonvagal AF. (3) This suggests that those in the vagal AF population have normal intraatrial conduction, which has implications for AF ablation in these patients.</AbstractText> |
7,902 | Are nonsustained ventricular tachycardias predictive of major arrhythmias in patients with dilated cardiomyopathy on optimal medical treatment? | To evaluate the role of nonsustained ventricular tachycardias (NSVT) for the prediction of major ventricular arrhythmias (MVA) in patients with idiopathic dilated cardiomyopathy (DCM) after optimization of medical treatment.</AbstractText>Three hundred nineteen consecutive DCM patients were evaluated after adequate stabilization on optimal angiotensin-converting enzyme (ACE) inhibitor (88%) and beta-blocker (82%) therapy. Frequency, length, and rate of NSVT at 24-hour Holter monitoring were analyzed to assess their values in predicting MVA (unexpected sudden death, SVT, ventricular fibrillation, and appropriate implantable cardioverter defibrillator interventions). During follow-up (median 96 months, 1(st)-3(rd) interquartile range 52-130), MVA incidence was low, and not statistically different between patients with and without NSVT (3 and 2 per 100 patient-years, respectively, P = nonsignificant [NS] at log-rank analysis). At multivariable analysis, the number of NSVT was predictive of MVA only if left ventricular ejection fraction (LVEF) was > 0.35 (two NSVT/day vs no NSVT/day: hazard ratio [HR] 5.3, 95% confidence interval [CI] 1.59-17.85 in LVEF > 0.35 vs HR 0.93, 95% CI 0.3-2.81 in LVEF < or = 0.35). Consequently, in patients with LVEF < or = 0.35, MVA incidence rates were similar regardless of NSVT (3.6 and 4.1 patient-years, respectively, in those with and without NSVT, P = NS), while in patients with LVEF > 0.35, MVA incidence (3.1 per 100 patient-years vs 0.9 per 100 patient-years, P = 0.003) was significantly higher when NSVT were present.</AbstractText>After medical stabilization, NSVT did not increase the risk of MVA in patients with DCM and LVEF < or = 0.35. Conversely, the number and length of NSVT runs were significantly related to the occurrence of MVA in the patients with LVEF > 0.35.</AbstractText> |
7,903 | [Effects of CASI on myocardial ischemia-reperfusion arrhythmia in rats]. | To observe the protective effect of compound acanthopanax senticosus injection (CASI) on myocardial ischemia-reperfusion arrhythmia in rats.</AbstractText>The myocardial ischemia-reperfusion model was induced by 30 min coronary occulusion and 60 min reperfusion in openchest anesthetized rats. The changes of arrhythmia with electrocardiogram lead II, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), the contents of malondialdehyde (MDA) and Ca2+ in myocardium were determined.</AbstractText>In rats treated by CASI (in a dosage of 25, 50 and 100 mg x kg(-1) femoral vein infusion at 30 min after coronary occulusion), the incidence of myocardial ischemia-reperfusion ventricular arrhythmias, for instance the ventricular tachycardia (VT) and ventricular fibrillation (Vf), was effectively prevented, the appearing time of arrhythmia was delayed and the duration of arrhythmia was shortened, while the elevated ST segment lowered as well. At the same time, the contents of myocardial Ca2+ and MDA were decreased significantly as well as the activities of myocardial SOD and GSH-Px increased markedly.</AbstractText>CASI is of protective effect on myocardial ischemia-reperfusion arrhythmia, which may be related to scavenging the oxygen free radicals and Ca2+ overload formed during reperfusion.</AbstractText> |
7,904 | Early complication after hybrid thoracic aortic aneurysm repair. | This brief report describes an unusual hybrid approach complication of aortic arch disease. An acute stent kinking in the first post-operative day promoted ventricular fibrillation and death. Adequate oversizing was achieved and intraoperative angiogram showed no proximal or distal leaks. Unfavorable outcomes are highly under-reported and describing complications are a key instrument to improve this technique. |
7,905 | Left atrial myxoma presenting with ventricular fibrillation. | Coronary artery embolism with myocardial infarction is a very rare and potentially life-threatening complication of left atrial myxoma. We report the case of a 51-year-old male who presented with chest pain. Whilst awaiting medical review in the emergency department, he collapsed and a cardiac monitor revealed ventricular fibrillation. Following successful resuscitation, a 12-lead electrocardiogram demonstrated anterior myocardial infarction that was initially presumed to be secondary to atheromatous coronary disease. An echocardiogram performed before discharge, however, revealed a mass in the left atrium, which was highly suggestive of a myxoma. His subsequent coronary angiogram demonstrated coronary disease limited to a single lesion within a small first obtuse marginal branch of his circumflex coronary artery. He underwent curative surgery, and histology confirmed the diagnosis of myxoma. We have discussed embolic complications of myxoma and the possible reasons for rarity of coronary embolisation. Emphasis is given to the importance of considering other causes of myocardial infarction in relatively young patients and the important role of early echocardiography following myocardial infarction. |
7,906 | Effect of atrial pacing on ventricular rate during atrial fibrillation. A human study. | This research study tests the hypothesis that atrial pacing near the atrioventricular node during atrial fibrillation can affect ventricular rate.</AbstractText>In 13 patients, two monophasic action potential catheters were advanced into the low anterior septum (ANT) and the low posterior septum (POST) near the atrioventricular node. After induction of atrial fibrillation, measurement of the excitable gap was attempted at the ANT and POST regions. During atrial pacing, ventricular cycle length (CL) at the longest excitable gap was compared to ventricular CL at the shortest excitable gap by pairwise analysis.</AbstractText>Transient capture of ANT tissue during ANT pacing was observed in six patients, whereas transient capture of POST tissue during POST pacing was observed in four patients. The ventricular response to ANT and POST pacing at multiple rates was recorded in six and seven patients, respectively. An increase in POST pacing CL by 40 +/- 24 ms prolonged (P < 0.05) ventricular CL by 45 +/- 56 ms. Conversely, an increase in ANT pacing CL by 48 +/- 42 ms shortened (P < 0.05) ventricular CL by 45 +/- 40 ms.</AbstractText>ANT and POST pacing CL affected ventricular CL during atrial fibrillation, even though capture was transient. The opposite direction of the effects of ANT and POST pacing CL on ventricular CL may indicate that the atrial impulses from the POST region are more likely to conduct to the ventricle than impulses from the ANT region as the CL of activation is decreased.</AbstractText> |
7,907 | Reduced incidence of new-onset atrial fibrillation with angiotensin II receptor blockade: the VALUE trial. | Atrial fibrillation (AF) is the most common arrhythmia and increases cardiovascular risk in hypertensive patients. Therefore, in the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) a prespecified objective was to compare the effects of valsartan and amlodipine on new-onset AF.</AbstractText>A total of 15 245 hypertensive patients at high cardiovascular risk received valsartan 80-160 mg/day or amlodipine 5-10 mg/day combined with additional antihypertensive agents. Electrocardiograms were obtained every year and analyzed centrally for evidence of left ventricular hypertrophy and new-onset AF.</AbstractText>At baseline, AF was diagnosed in 2.6% of 7649 valsartan recipients and 2.6% of 7596 amlodipine recipients. During antihypertensive treatment the incidence of at least one documented occurrence of new-onset AF was 3.67% with valsartan and 4.34% with amlodipine [unadjusted hazard ratio 0.843, [95% confidence interval (CI): 0.713, 0.997], P = 0.0455]. The incidence of persistent AF was 1.35% with valsartan and 1.97% with amlodipine [unadjusted hazard ratio 0.683 (95% CI: 0.525, 0.889), P = 0.0046].</AbstractText>Valsartan-based treatment reduced the development of new-onset AF, particularly sustained AF in hypertensive patients, compared with amlodipine-based therapy. These findings suggest that angiotensin II receptor blockers may result in greater benefits than calcium antagonists in hypertensive patients at risk of new-onset AF.</AbstractText> |
7,908 | P wave dispersion is prolonged in patients with Wilson's disease. | To investigate the P wave dispersion as a non-invasive marker of intra-atrial conduction disturbances in patients with Wilson's disease.</AbstractText>We compared Wilsonos disease patients (n = 18) with age matched healthy subjects (n = 15) as controls. The diagnosis was based on clinical symptoms, laboratory tests (ceruloplasmin, urinary and hepatic copper concentrations). P wave dispersion, a measurement of the heterogeneity of atrial depolarization, was measured as the difference between the duration of the longest and the shortest P-waves in 12 lead electrocardiography.</AbstractText>All the patients were asymptomatic on cardiological examination and have sinusal rhythm in electrocardiography. Left ventricular and left atrial diameters, left ventricular ejection fraction and left ventricular mass index were similar in both groups. The Wilson's disease patients had a significantly higher P wave dispersion compared with the controls (44.7 +/- 5.8 vs 25.7 +/- 2.5, P < 0.01).</AbstractText>There was an increase in P wave dispersion in cardiologically asymptomatic Wilson's disease patients which probably represents an early stage of cardiac involvement.</AbstractText> |
7,909 | Incidence of ventricular fibrillation during left coronary arteriography in pigs: comparison of a solution of the nonionic dimer iodixanol with solutions of five different nonionic monomers. | Solutions of iodine contrast media (CM) used for selective coronary arteriography (CA) should have minimal propensity to cause ventricular fibrillation (VF). Commonly used CM for CA are nonionic monomers or dimers.</AbstractText>To compare VF propensity of ready-to-use solutions of one nonionic dimer, iodixanol, and five nonionic monomers, iobitridol, iopamidol, iomeprol, iopromide, and ioversol.</AbstractText>Twenty milliliters of each CM was injected into the left coronary artery (LCA) through an inflated balloon catheter (0.5 ml/s) in 14 pigs; the longest period of injection was 40 s. If VF occurred before 40 s, the injection was stopped and the heart was defibrillated. After VF, there was a delay of 40 min before the next injection. Hemodynamic parameters and vector electrocardiography (VECG) were monitored. A CM with a lower frequency of VF and a longer period between start of injection and start of VF was considered to have a lower VF propensity.</AbstractText>Following 14 injections, each of the five nonionic monomers caused 14 VF, whereas iodixanol caused three VF (P<0.01). When VF occurred after iodixanol, it occurred later than after the other CM (P<0.001). Iodixanol caused less prolongation in QRS time (P<0.01) and QTc time (P<0.05) than the other CM. Prolongations in QRS and QTc times caused by CM parallel the VF propensities of the CM.</AbstractText>Ready-to-use solutions of the dimer iodixanol have lower VF propensity than solutions of the five monomeric CM. This is related to the fact that the solutions of the dimer iodixanol have lower osmolality, higher viscosity, and higher concentrations of NaCl and CaCl2 than solutions of the five monomers.</AbstractText> |
7,910 | Short-term normalization of ventricular repolarization by transcatheter ablation in a patient with suspected Brugada Syndrome. | We report a 30 year old male without structural heart disease who presented with recurrent nocturnal syncope and aborted sudden cardiac death. 12-lead ECG showed elevated ST in inferior leads and short coupled premature ventricular complexes (PVCs). Propafenone challenge suggested a diagnosis of an atypical Brugada syndrome. Two morphological types of PVCs and ventricular fibrillation (VF) were induced during propafenone challenge test. He underwent two ablation procedures in right ventricular inflow tract and left ventricular post-inferior septum region by pace-mapping, respectively. After ablation, VF could not be induced and the elevated ST segments normalized. Two subsequent propafenone challenge tests were also negative. Nonetheless, elevated ST segments and PVCs reappeared by 1 month follow-up. An implantable defibrillator was recommended, but the patient declined for financial reasons. Unfortunately, he suffered a sudden cardiac death at home 10 weeks post-ablation. These findings suggest that short-term normalization of ventricular repolarization possibly due to radiofrequency ablation may occur in Brugada syndrome. However, the transient nature of this finding suggests that it is not a reliable indicator of protection against sudden cardiac death. |
7,911 | Is defibrillation testing still necessary? A decision analysis and Markov model. | To assess the impact of defibrillation threshold (DFT) testing of implanted cardioverter-defibrillators (ICDs) on survival.</AbstractText>DFT testing is generally performed during implantation of ICDs to assess sensing and termination of ventricular fibrillation. It is common clinical practice to defibrillate ventricular fibrillation twice at an output at least 10 J below the maximum output of the device, providing a 10 J safety margin. However, there are few data regarding impact of DFT testing on outcomes.</AbstractText>Decision analysis and Monte Carlo simulation were used to assess expected outcomes of DFT testing. Survival of a hypothetical cohort of patients was assessed according to two strategies-routine DFT testing at time of ICD implant versus no DFT testing. Assumptions in the model were varied over a range of reasonable values to assess outcomes under a variety of scenarios.</AbstractText>Five-year survival with DFT and no-DFT strategies were similar at 59.72% and 59.36%, respectively. The results were not sensitive to changing risk estimates for arrhythmia incidence and safety margin. Results of the Monte Carlo simulation were qualitatively similar to the base case scenario and consistent with a small and nonsignificant survival advantage with routine DFT testing.</AbstractText>The impact of DFT testing on 5-year survival in ICD patients, if it exists, is small. Survival appears higher with DFT testing as long as annual risk of lethal arrhythmia or the risk of a narrow safety margin is at least 5%, although the incremental benefit is marginal and 95% confidence intervals cross zero. A prospective randomized study of DFT testing in modern devices is warranted.</AbstractText> |
7,912 | Effect of single dose magnesium on arrhythmias in patients undergoing coronary artery bypass surgery. | To evaluate the safety and role of prophylactic administration of magnesium in preventing arrhythmias.</AbstractText>This double blind randomized placebo controlled clinical trial was conducted at Aga Khan University Hospital on coronary artery bypass surgery patients. All patients were connected to holter monitor before induction of anaesthesia and this monitoring continued for 24 hours. Study drug containing either 2-grams of magnesium or normal saline was given after intubation. Levels of serum magnesium was checked preoperatively and then in ICU at 0, 6, 12, and 24 hours. Independent t-test and chi square test were used for analysis. Statistical significance was defined as p-value < 0.05.</AbstractText>A total of 104 patients consented to participate in the study, 53 patients were randomly allocated in magnesium (Mg) group and 51 in placebo group. Two (3.77%) patients in magnesium group and five patients (9.8%) in placebo group developed atrial fibrillation. Incidence of ventricular and supraventricular tachycardia was also slightly higher in placebo. Mg level after arrival in CICU (Cardiac Intensive Care Unit) showed mean of 2.1 in magnesium group and 1.6 in placebo group (p = 0.6).</AbstractText>Low magnesium levels were noticed in the placebo group after cardiopulmonary bypass and although prophylactic administration of magnesium sulphate was relatively safe but significant benefit on prevention of arrhythmias could not be attained.</AbstractText> |
7,913 | Endoscopic thoracic sympathectomy for long QT syndrome. | A 54-year-old woman was referred to our service with intractable ventricular arrhythmias secondary to a familial long-QT syndrome. Her first presentation was 4 years previously, when she suffered a cardiac arrest, at this time an (Automatic Implantable Cardioverter Defibrillator) AICD device was inserted and she was commenced on sympathetic blockers. She remained symptomatic with ongoing tachyarrhythmias and the subsequent automatic cardioversion or defibrillation was causing significant amount of distress.</AbstractText>She underwent a left transthoracic endoscopic cardiac sympathectomy and made a good postoperative recovery. She remains asymptomatic at four months.</AbstractText>Though open sympathectomy is an established treatment, there are only isolated reports of thoracoscopic sympathetic cardiac denervation in the literature.</AbstractText> |
7,914 | Systolic dysfunction in urban Japan. | Heart failure (HF), which can be caused by left ventricular systolic dysfunction (LVSD), is a growing problem in developed countries with a large aging population. The aim of the present study was to characterize outpatients with LVSD in the adult population (45-84 years) in an urban Japanese community (Niigata City), and delineate their characteristics in comparison with those in a rural one (Sado).</AbstractText>Over a 5-year period, 1,297 patients (67% males) with LVSD (defined as ejection fraction < or =50%) were extracted from 87,953 echocardiography records available in 15 hospitals in Niigata City. The proportion of LVSD increased progressively with age (p-for-trend <0.0001), reaching 1-2% in those aged > or =75 years. The prevalence of comorbidities was noticeable (47% had hypertension, 41% myocardial ischemia, 34% atrial fibrillation, 33% previous hospitalization because of congestive HF, 27% cerebral stroke). In comparison with Sado, Niigata patients were younger, with a higher prevalence of comorbidities (hypertension, diabetes, dyslipidemia, and cerebral stroke).</AbstractText>As the proportion of LVSD cases increases progressively with age, it is expected to simulate a future epidemic. The differences between patients' characteristics and disease patterns in urban and rural communities may favor individually tailoring preventive strategies for HF in these areas.</AbstractText> |
7,915 | An unusual case of isolated non-compacted right ventricular myocardium. | Isolated ventricular non-compaction is a rare type of cardiomyopathy resulting from arrested myocardial development during embryogenesis. This rare entity can be easily diagnosed by characteristic appearance of prominent myocardial trabeculations and deep inter-trabecular spaces. The clinical manifestations include heart failure signs, ventricular arrhythmias, and cardio-embolic events. Although the usual site of involvement is the left ventricle, the right ventricle (RV) can rarely be affected. Here, we report a case of 23-year-old male patient with isolated RV non-compaction. |
7,916 | "Torsade de pointes" during amiodarone infusion in a cirrhotic woman with a prolonged QT interval. | We describe an interesting case of a woman with decompensated cirrhosis, ischaemic heart disease and prolonged QT interval, who developed a new-onset atrial fibrillation. During amiodarone infusion a torsade de pointes occurred, which was immediately converted to sinus rhythm by synchronized cardioversion. A new episode of atrial fibrillation was treated with infusion of a beta-blocker (metoprolol) that restored sinus rhythm and normalized the QT interval. Delayed repolarization, frequently observed in ischaemic heart disease, cirrhosis and pro-arrhythmic drugs administration, represents the background for the development of torsade de pointes. Our report underlines that the potential harmfulness of a prolonged QT interval in cirrhotic patients is currently not perceived in its entirety, so that various categories of drugs affecting ventricular repolarization are rather thoughtlessly used in clinical practice without monitoring the QT interval. Thus, amiodarone should be avoided, if possible, or used with extreme care in arrhythmic patients with advanced liver disease. Moreover, beta-blockers may be considered the first-line treatment for rate-control during supraventricular tachyarrhythmias in cirrhotic patients with delayed repolarization. |
7,917 | Anatomically determined functional conduction delay in the posterior left atrium relationship to structural heart disease. | This study sought to characterize the conduction properties of the posterior left atrium (PLA) in patients with different forms of structural heart disease undergoing cardiac surgery.</AbstractText>The PLA plays an important role in the initiation and maintenance of atrial fibrillation.</AbstractText>This study included 34 patients having elective cardiac surgery. There were 4 groups of patients: normal left ventricular (LV) function (coronary artery bypass grafting [CABG]); severe LV dysfunction (LVF/CABG); severe mitral regurgitation (MR); severe aortic stenosis (AS). Epicardial mapping of the PLA was performed in sinus rhythm and during differential pacing. Activation patterns, regional conduction velocity (CV), conduction heterogeneity, anisotropy, and total plaque activation time (TAT) were assessed.</AbstractText>Left atrial size in patients with LVF/CABG (47 +/- 7 mm) and MR (54 +/- 6 mm) was larger than patients with CABG (39 +/- 7 mm) and AS (42 +/- 6 mm; p < 0.05). During pacing, all patients developed a vertical line of conduction delay running between the pulmonary veins. The extent of this conduction delay was greater in patients with LVF/CABG and MR than patients with AS and CABG (p < 0.05). Conduction heterogeneity, anisotropy, and TAT were greater in patients with LVF/CABG and MR than patients with CABG (p < 0.05). These changes resulted in circuitous wave front propagation.</AbstractText>There is a line of functional conduction delay in a consistent anatomical location in the PLA in patients with structural heart disease. This is most marked in conditions associated with significant chronic atrial enlargement and leads to circuitous wave front propagation, suggesting a potential role in arrhythmogenesis.</AbstractText> |
7,918 | Long-term follow-up after cryothermic ostial pulmonary vein isolation in paroxysmal atrial fibrillation. | This study was designed to evaluate the long-term effect of segmental pulmonary vein (PV) cryoablation in patients with recent-onset paroxysmal atrial fibrillation (PAF).</AbstractText>Patients with PAF have more triggers to initiate and less substrate to sustain atrial fibrillation (AF). Elimination of the potential initiators alone may be sufficient to abolish the arrhythmia.</AbstractText>Patients with PAF were prospectively recruited from July 2001 to July 2005. If the triggers for AF were identified, PV cryoisolation of the arrhythmogenic vein(s) was performed. Otherwise, all PVs were isolated.</AbstractText>Seventy patients with minimal or no heart disease (54 men; age 40 +/- 10 years) were enrolled. The duration of AF was 4 +/- 1 year. The left ventricular ejection fraction and left atrial size were 59 +/- 8% and 41 +/- 5 mm, respectively. An arrhythmogenic PV was found in 10 patients (14%). Complications occurred in 3 patients (4%). No PV stenosis or esophageal injury was detected during a mean follow-up of 33 +/- 15 months. Thirty-four patients (49%) achieved complete success (no AF and no antiarrhythmic drugs [AAD]); 15 patients (22%) had no recurrences with AAD; and 8 patients (11%), still with sporadic bursts of AF, improved >50% with AAD. Overall, 82% of the patients benefited from the procedure. Patients in whom the arrhythmogenic PV was identified and isolated had no recurrences.</AbstractText>Pulmonary vein cryoisolation is effective in 82% of patients with recent-onset PAF during a mean follow-up of 33 +/- 15 (range 15 to 60) months. If the arrhythmogenic PV is identified and isolated, the long-term outcome is excellent, indicating no need to isolate all PVs.</AbstractText> |
7,919 | Persistent atrial fibrillation is associated with reduced risk of torsades de pointes in patients with drug-induced long QT syndrome. | The goal of this study was to identify markers of torsades de pointes (TdP) in patients with drug-associated long QT syndrome (LQTS).</AbstractText>Drug-induced LQTS includes individuals developing marked prolongation of ventricular repolarization on exposure to an offending drug. Under these conditions, TdP develops in some but not all patients.</AbstractText>This was a case-control study of 123 adults with drug-associated LQTS. Patients were divided into LQTS only (LQTS; n = 40, QT >500 ms on drug) and LQTS + TdP (TdP; n = 83).</AbstractText>Baseline QT intervals were similar in the 2 groups (381 +/- 38 ms [LQTS] vs. 388 +/- 43 ms [TdP]). Clinical variables associated with risk of TdP included hypokalemia and female gender; by contrast, persistent atrial fibrillation (AF) at the time of drug discontinuation for QT prolongation was protective despite similar heart rates in AF and sinus rhythm (n = 20, 71 +/- 13 beats/min vs. 69 +/- 13 beats/min). Electrocardiographic variables that significantly increased the risk for TdP included absolute and rate-corrected QT intervals (QTc) on drug therapy, the magnitude of QT and QTc interval prolongation, and the change in T(peak) to T(end) (DeltaT(p)-T(e)), a relatively new index of transmural dispersion of repolarization and potential arrhythmogenicity. Multivariable logistic regression analysis revealed that only gender was predictive for TdP, whereas persistent AF at the time of drug discontinuation for QT prolongation (odds ratio 0.14, 95% confidence interval 0.03 to 0.63, p = 0.01) was negatively associated with the arrhythmia.</AbstractText>This study strongly suggests that despite ongoing rate irregularity, AF reduces the likelihood of developing TdP after the administration of drugs that prolong cardiac repolarization.</AbstractText> |
7,920 | Atrial-selective approaches for the treatment of atrial fibrillation. | Atrial-selective pharmacologic approaches represent promising novel therapeutic options for the treatment of atrial fibrillation (AF). Medical treatment for AF is still more widely applied than interventional therapies but is hampered by several important weaknesses. Besides limited clinical efficacy (cardioversion success and sinus-rhythm maintenance), side effects like ventricular proarrhythmia and negative inotropy are important limitations to present class I and III drug therapy. Although no statistically significant detrimental survival consequences have been documented in trials, constitutional adverse effects might also limit applicability. Cardiac targets for novel atrial-selective antiarrhythmic compounds have been identified, and a large-scale search for safe and effective medications has begun. Several ionic currents (I(KACh), I(Kur)) and connexins (Cx-40) are potential targets, because atrial-selective expression makes them attractive in terms of reduced ventricular side-effect liability. Data on most agents are still experimental, but some clinical findings are available. Atrial fibrillation generates a specifically remodeled atrial milieu for which other therapeutic interventions might be effective. Some drugs show frequency-dependent action, whereas others target structurally remodeled atria. This review focuses on potential atrial-selective compounds, summarizing mechanisms of action in vitro and in vivo. It also mentions favorable interventions on the milieu in terms of conventional (such as antifibrotic effects of angiotensin-system antagonism) and innovative gene-therapy approaches that might add to future AF therapeutic options. |
7,921 | Rationale and design of the Home Automatic External Defibrillator Trial (HAT). | Most cardiac arrests occur in the home, where emergency medical services (EMS) systems are challenged to provide timely care. Because a large proportion of sudden cardiac arrests (SCAs) are due to ventricular tachycardia or ventricular fibrillation, home use of an automated external defibrillator (AED) might offer an opportunity to decrease mortality in those at risk. Predicting who will have a cardiac arrest in the general population is difficult. Individuals at high risk are usually easily identified and may become candidates for implantable cardioverter defibrillators. It is within the population at lower risk where home AEDs may be most useful. The purpose of the Home Automatic External Defibrillator Trial (HAT) is to test whether providing home access to an AED can improve survival in patients at modest risk of SCA, such as those surviving an anterior myocardial infarction but in whom implantable cardioverter defibrillator therapy is not deemed necessary. Between January 23, 2003, and October 20, 2005, 7001 patients were enrolled, with completion of follow-up scheduled for September 30, 2007. Randomization was conducted in a 1:1 fashion between control therapy, comprising the standard lay response to SCA (calling the EMS and performing cardiopulmonary resuscitation), and the use of an AED first, followed by calling the EMS and performing cardiopulmonary resuscitation. The primary end point is all-cause mortality. Secondary outcomes include survival from SCA (witnessed and unwitnessed, in home and out of home), incremental cost-effectiveness, and quality of life measures for both the patient and the spouse/companion. The results of the trial should be available in mid 2008. |
7,922 | Experimental study of pegylated liposomal hemoglobin on norepinephrine release and reperfusion arrhythmias in isolated guinea pig hearts. | Under myocardial reperfusion conditions, hemoglobin (Hb)-based artificial blood showed effectiveness for post-ischemic dysfunction. However, there are no studies about the effects of this product on reperfusion arrhythmias (ventricular fibrillation, VF) associated with norepinephrine (NE) release. This study was to evaluate the effects of the timing of the administration of pegylated liposomal Hb (LHb, P(50)=40-45 mmHg, 1 mg/mL) on NE release and VF.</AbstractText>Isolated guinea pig hearts (n=6 in each group) were randomly divided into four groups in Krebs-Henseleit solution being supplemented or not with LHb as follows: pre-ischemia (PRE), reperfusion (REP), or PRE+REP groups. The hearts were perfused for 30 min (preischemic period) and then subjected to 30 min of global ischemia, followed by 30 min of reperfusion with a normothermic Langendorff apparatus at 30 mm Hg aortic pressure in a constant pressure model.</AbstractText>No differences were documented among the four groups in heart rate, left ventricular-developed pressure, or coronary flow rate. However, the REP group significantly decreased the duration of VF and NE release, but it did not inhibit the incidence of VF.</AbstractText>These results suggest that the administration of LHb, especially with the timing of reperfusion, might prevent reperfusion arrhythmias linked to the inhibition of NE release.</AbstractText> |
7,923 | Recurrence of mitral regurgitation parallels the absence of left ventricular reverse remodeling after mitral repair in advanced dilated cardiomyopathy. | The aim of this study was to assess the occurrence of reverse left ventricular (LV) remodeling after effective mitral valve repair in advanced dilated cardiomyopathy and its impact on clinical outcome and repair durability.</AbstractText>Of 111 patients undergoing mitral valve repair in ischemic or idiopathic dilated cardiomyopathy, 79 patients with no or trivial residual mitral regurgitation (MR) at discharge and with a follow-up length of at least 6 months were included in this study. Preoperatively they had 3 to 4+ functional MR, an ejection fraction of 0.28 +/- 0.055, an indexed LV end-diastolic volume of 113 +/- 33.0 mL/m2, an indexed LV end-systolic volume of 80.8 +/- 26.3 mL/m2, a tenting area of 2.7 +/- 0.9 cm2, and a coaptation depth of 1.1 +/- 0.3 cm. Sixty-three patients (79.8%) were in New York Heart Association class III or IV. A complete, rigid or semirigid undersized ring annuloplasty (with or without "edge-to-edge") was used. Concomitant procedures were coronary artery bypass grafting (49 of 79 patients, 62%), tricuspid valve repair (11 of 79 patients, 13.9%), and ablation of permanent atrial fibrillation (13 of 79 patients, 16.4%).</AbstractText>At a mean follow-up of 2 +/- 1.3 years (median, 1.8 years), LV reverse remodeling was documented in 41 patients (51.8%), whereas in 38 patients (48.1%) LV dimensions remained unchanged or increased compared with preoperative values. The persistence or progression of LV remodeling paralleled the recurrence of MR and worsening of symptoms. Recurrence of MR of 3+ or greater was 0% in the "reverse remodeling" group and 18.4% in the "no reverse remodeling" one (p = 0.008). At 3 years, freedom from recurrence of MR of 2+ or greater was 74% +/- 11.7% and 62% +/- 9.2% (p = 0.004) and New York Heart Association class was 1.5 +/- 0.61 and 2 +/- 0.72 (p < 0.0001), respectively. Predictors of reverse remodeling were ischemic etiology (p = 0.04), concomitant coronary artery bypass grafting (p = 0.02), successful ablation of atrial fibrillation (p = 0.05), and shorter history of congestive heart failure (p = 0.06). The use of the edge-to-edge showed a trend toward favoring reverse remodeling compared with isolated annuloplasty (p = 0.08).</AbstractText>In patients with functional MR undergoing effective repair, the occurrence of reverse LV remodeling is associated with longer repair durability and a better clinical outcome compared with those with persistence or progression of the remodeling process.</AbstractText> |
7,924 | [Constrictive pericarditis or restrictive cardiomyopathy? Echocardiographic tissue Doppler analysis]. | Echocardiographic tissue Doppler imaging (TDI) has been proposed for differentiating between constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM). The aim of this retrospective study was to analyse TDI in patients with severe diastolic dysfunction associated with proven constrictive pericarditis or restrictive cardiomyopathy.</AbstractText>The cohort included 34 consecutive patients (24 men. 10 women; mean age 58 12 years), 20 of whom had proven CP (pericardectomy) and 14 had RCM due to amyloidosis (proven by biopsy). Tissue Doppler Imaging was performed online by pulsed-wave TDI at the lateral and septal mitral annulus in the four-chamber view. Filling pressures were measured invasively.</AbstractText>20 of the 34 patients (60%) were in NYHA class III. 19 of the 34 patients were in sinus rhythm (56 %) and 15 had atrial fibrillation. Left ventricular systolic function was normal in all patients with CP. Eight patients with RCM had normal, 3 patients near normal and 3 patients slightly impaired left ventricular contractile function (EF 50-55% and EF 40%, respectively). Respiratory variation of the transmitral inflow was increased in 10 of 12 patients with CP and sinus rhythm. TDI of the early diastolic velocity across the mitral annulus E} was significantly higher in patients with CP than in those with RCM at the septal and at the lateral mitral annulus (13.8 4.2 cm/s vs. 4.0 1.2 cm/s; p < 0.01 and 11.4 3.4 cm/s vs. 4.4 1.7 cm/s; p < 0.01, respectively). A cut-off value 8 cm/s for the diagnosis of RCM showed a sensitivity of 100% and a specificity of 90% (septal) and 80% (lateral), respectively. The E/E}ratio also was significantly different between both groups (septal: 11.2 8.8 vs. 25.1 8.7; p < 0.01).</AbstractText>TDI of the early diastolic velocity of the mitral annulus E} makes it possible to differentiate between constrictive pericarditis and restrictive cardiomyopathy and should be part of the echocardiographic work-up in clinical routine.</AbstractText> |
7,925 | Characterization of in vivo and in vitro electrophysiological and antiarrhythmic effects of a novel IKACh blocker, NIP-151: a comparison with an IKr-blocker dofetilide. | We investigated the electrophysiological and antiarrhythmic effects of a novel antiarrhythmic agent, NIP-151, and compared these effects with those of an IKr-blocker dofetilide. NIP-151 potently inhibited acetylcholine-activated K current (IKACh) with an IC50, with 1.6 nM in HEK293 cells expressing the GIRK1/4 channel, but it had little effect on IKr (IC50 = 57.6 microM). NIP-151 dose-dependently terminated AF both in vagal nerve stimulation-induced AF (at 5 and 15 microg/kg per minute) and aconitine-induced AF (at 30 and 100 microg/kg) models. This compound significantly prolonged the atrial effective refractory period (ERP), but it had no significant effects on ventricular ERP. There were no significant changes on electrocardiographic variables with NIP-151 (up to 1,000 microg/kg per minute) administration. In contrast, dofetilide had little effect in either AF model, even though this compound potently prolonged atrial ERP. Dofetilide also significantly prolonged ventricular ERP and the QT interval in anesthetized dogs, which are related to proarrhythmic risk. In conclusion, a novel antiarrhythmic agent NIP-151, which potently blocked IKACh, was highly effective in the two types of canine AF models with an atrial-specific ERP-prolonging profile. Therefore, NIP-151 might be useful for the treatment of AF with lower risk of proarrhythmia, compared with IKr blockers. |
7,926 | [Clinical case of the month. Atrial flutter with rapid ventricular response (1:1 atrioventricular conduction) caused by flecaïnide]. | We report a case of 1:1 flutter in a patient taking flecaïnide for atrial fibrillation. We discuss the mechanism of the arrhythmia, its treatment and the preventive attitude to be adopted. |
7,927 | Survival from in-hospital cardiac arrest during nights and weekends. | Occurrence of in-hospital cardiac arrest and survival patterns have not been characterized by time of day or day of week. Patient physiology and process of care for in-hospital cardiac arrest may be different at night and on weekends because of hospital factors unrelated to patient, event, or location variables.</AbstractText>To determine whether outcomes after in-hospital cardiac arrest differ during nights and weekends compared with days/evenings and weekdays.</AbstractText>We examined survival from cardiac arrest in hourly time segments, defining day/evening as 7:00 am to 10:59 pm, night as 11:00 pm to 6:59 am, and weekend as 11:00 pm on Friday to 6:59 am on Monday, in 86,748 adult, consecutive in-hospital cardiac arrest events in the National Registry of Cardiopulmonary Resuscitation obtained from 507 medical/surgical participating hospitals from January 1, 2000, through February 1, 2007.</AbstractText>The primary outcome of survival to discharge and secondary outcomes of survival of the event, 24-hour survival, and favorable neurological outcome were compared using odds ratios and multivariable logistic regression analysis. Point estimates of survival outcomes are reported as percentages with 95% confidence intervals (95% CIs).</AbstractText>A total of 58,593 cases of in-hospital cardiac arrest occurred during day/evening hours (including 43,483 on weekdays and 15,110 on weekends), and 28,155 cases occurred during night hours (including 20,365 on weekdays and 7790 on weekends). Rates of survival to discharge (14.7% [95% CI, 14.3%-15.1%] vs 19.8% [95% CI, 19.5%-20.1%], return of spontaneous circulation for longer than 20 minutes (44.7% [95% CI, 44.1%-45.3%] vs 51.1% [95% CI, 50.7%-51.5%]), survival at 24 hours (28.9% [95% CI, 28.4%-29.4%] vs 35.4% [95% CI, 35.0%-35.8%]), and favorable neurological outcomes (11.0% [95% CI, 10.6%-11.4%] vs 15.2% [95% CI, 14.9%-15.5%]) were substantially lower during the night compared with day/evening (all P values < .001). The first documented rhythm at night was more frequently asystole (39.6% [95% CI, 39.0%-40.2%] vs 33.5% [95% CI, 33.2%-33.9%], P < .001) and less frequently ventricular fibrillation (19.8% [95% CI, 19.3%-20.2%] vs 22.9% [95% CI, 22.6%-23.2%], P < .001). Among in-hospital cardiac arrests occurring during day/evening hours, survival was higher on weekdays (20.6% [95% CI, 20.3%-21%]) than on weekends (17.4% [95% CI, 16.8%-18%]; odds ratio, 1.15 [95% CI, 1.09-1.22]), whereas among in-hospital cardiac arrests occurring during night hours, survival to discharge was similar on weekdays (14.6% [95% CI, 14.1%-15.2%]) and on weekends (14.8% [95% CI, 14.1%-15.2%]; odds ratio, 1.02 [95% CI, 0.94-1.11]).</AbstractText>Survival rates from in-hospital cardiac arrest are lower during nights and weekends, even when adjusted for potentially confounding patient, event, and hospital characteristics.</AbstractText> |
7,928 | Effects of wall stress on the dynamics of ventricular fibrillation: a simulation study using a dynamic mechanoelectric model of ventricular tissue. | To investigate the mechanisms underlying the increased prevalence of ventricular fibrillation (VF) in the mechanically compromised heart, we developed a fully coupled electromechanical model of the human ventricular myocardium.</AbstractText>The model formulated the biophysics of specific ionic currents, excitation-contraction coupling, anisotropic nonlinear deformation of the myocardium, and mechanoelectric feedback (MEF) through stretch-activated channels. Our model suggests that sustained stretches shorten the action potential duration (APD) and flatten the electrical restitution curve, whereas stretches applied at the wavefront prolong the APD. Using this model, we examined the effects of mechanical stresses on the dynamics of spiral reentry. The strain distribution during spiral reentry was complex, and a high strain-gradient region was located in the core of the spiral wave. The wavefront around the core was highly stretched, even at lower pressures, resulting in prolongation of the APD and extension of the refractory area in the wavetail. As the left ventricular pressure increased, the stretched area became wider and the refractory area was further extended. The extended refractory area in the wavetail facilitated the wave breakup and meandering of tips through interactions between the wavefront and wavetail.</AbstractText>This simulation study indicates that mechanical loading promotes meandering and wave breaks of spiral reentry through MEF. Mechanical loading under pathological conditions may contribute to the maintenance of VF through these mechanisms.</AbstractText> |
7,929 | How to avoid inappropriate therapy. | With wider indications for implantable cardioverter defibrillator therapy, more patients at lower risk for ventricular tachyarrhythmia receive this treatment. To maintain the ratio of benefit versus side-effects at an acceptable level, the risk of inappropriate implantable cardioverter defibrillator therapy has to be minimized.</AbstractText>Implantable cardioverter defibrillators require the activation of enhanced detection criteria. These can avoid inappropriate therapy of sinus tachycardia (gradual onset) and atrial fibrillation (irregular rate) while other regular supraventricular tachycardias may be misclassified even with combinations of criteria (QRS morphology, abrupt onset, regular rate). Carefully programmed, dual-chamber implantable cardioverter defibrillators provide better ventricular tachyarrhythmia/supraventricular tachycardias discrimination. Key issues are long tachycardia detection (18 cycles or more), deactivation or restrictive programming of safety therapy despite supraventricular tachycardia classification, and restriction of shock therapy to high tachycardia rates (>or=250 bpm). Further developments are necessary to reduce the incidence of inappropriate therapy due to lead failure that is more frequent in physically active patients.</AbstractText>With optimized programming, the rate of inappropriate ventricular tachyarrhythmia detection is significantly reduced. Particularly the prevention of inappropriate shocks has important implication for the quality of life and acceptance of implantable cardioverter defibrillator treatment.</AbstractText> |
7,930 | Clinical significance of pacemaker-detected atrial high-rate episodes. | Pacemakers currently being implanted offer several advanced diagnostic features. Among these is the ability to store counters and intracardiac electrograms of individual atrial high-rate episodes, which are a surrogate of atrial fibrillation. As the majority of these episodes are brief and asymptomatic, their clinical significance remains to be determined. The purpose of this review is to provide a better understanding of the clinical significance of pacemaker-detected atrial high-rate episodes.</AbstractText>Follow-up after dual-chamber pacemaker implantation demonstrates that nearly 30% of patients without a known history of atrial fibrillation develop an atrial high-rate episode lasting 5 min or more. Patients experiencing such an episode are at a twofold increased risk of stroke and death. An important risk factor for developing an atrial high-rate episode is a high burden of right ventricular pacing, suggesting that ventricular pacing should be minimized whenever possible.</AbstractText>Atrial high-rate episodes are frequently observed in patients after dual-chamber pacemaker implantation and can be associated with adverse outcomes. Ongoing studies seek to determine whether the overall burden of these episodes correlates with the risk of thromboembolism, especially in patients without a history of atrial fibrillation, which would help guide decision-making regarding the initiation of anticoagulation.</AbstractText> |
7,931 | Cardiac resynchronization therapy in the setting of permanent atrial fibrillation and heart failure. | Heart failure and atrial fibrillation have been called the twin modern epidemics. They are often present concomitantly and are believed to directly predispose to each other. They form a sinister synergy, and management of atrial fibrillation in the setting of heart failure is challenging; relatively new therapeutic strategies like cardiac resynchronization therapy and catheter ablation need to be validated in this complex setting. This review will summarize the current management strategies of atrial fibrillation in the setting of heart failure.</AbstractText>Recent observational studies and a single randomized trial point towards a potential benefit of cardiac resynchronization therapy in heart-failure patients with permanent atrial fibrillation; particularly, biventricular pacing was superior compared with conventional right-ventricular stimulation. However, recent results suggest that even a relatively high-percentage biventricular capture may be inadequate, and that the benefits of cardiac resynchronization therapy may only be extended to chronic atrial fibrillation patients with previous atrioventricular junctional ablation.</AbstractText>Rigorously designed clinical studies are needed to clarify the role of ablation, resynchronization therapy and drugs when atrial fibrillation complicates the course of heart failure.</AbstractText> |
7,932 | An unusual diagnosis of atrial shunt defect by magnetic resonance imaging. | Paroxysmal atrial arrhythmias especially atrial fibrillation are frequently encountered in adult patients with atrial septal defect. However, the diagnosis of atrial defect can be difficult. Thransthoracic echocardiography, the mostly utilized cardiac technique, has shown a limited ability to identify small atrial defects. Transesophageal echocardiography has shown high accuracy to identify but it isn't well tolerated of the patients. Recently, the utility of multislice computed tomography in the evaluation of direction, location, and size of shunt flow in congenital heart disease has been demonstrated. Cardiac magnetic resonance imaging (MRI) is a recent imaging technique that permits with high spatial resolution and without ionising radiation an accurate identification of many cardiovascular diseases. We report an unusual detection of an atrial defect by phase-contrast cine MRI in a patient clinically suspected of arrhitmogenic right ventricular displasia. |
7,933 | Cerebral cortical microvascular flow during and following cardiopulmonary resuscitation after short duration of cardiac arrest. | To examine changes in cerebral cortical macro- and microcirculation and their relationship to the severity of brain ischaemia during and following resuscitation from a short duration of cardiac arrest.</AbstractText>Bilateral cranial windows were created in eight domestic pigs weighing 41+/-1 kg, exposing the frontoparietal cortex for orthogonal polarization spectral imaging together with estimation of cortical-tissue partial pressure of carbon dioxide, a quantitator of the severity of cerebral ischaemia. After 3 min of untreated ventricular fibrillation, cardiopulmonary resuscitation was begun and continued for 4 min before defibrillation. Aortic pressure, end-tidal and cortical-tissue partial pressure of carbon dioxide, and cortical microcirculatory blood flow in vessels of less and more than 20 microm in diameter were continuously measured.</AbstractText>Cerebral microcirculatory blood flow progressively decreased over the 3-min interval that followed onset of ventricular fibrillation. Chest compression restored cortical microvascular flow to approximately 40% of the pre-arrest value. Following return of spontaneous circulation, microvascular flow velocity was restored to baseline values over 3 min. Reversal of cerebral ischaemia with normalisation of cerebral cortical-tissue partial pressure of carbon dioxide occurred over 7 min after resuscitation. Cortical microcirculatory blood flow in microvessels less than 20 microm was highly correlated with flow in vessels more than 20 microm together with mean aortic pressure and end-tidal partial pressure of carbon dioxide.</AbstractText>Cerebral cortical microcirculatory flow ceased only 3 min after onset of cardiac arrest. Flow was promptly restored to 40% of its pre-arrest value after start of chest compression. After resuscitation, both macro- and microcirculatory flows were fully restored over 3 min, but cerebral ischaemia reversed more slowly.</AbstractText> |
7,934 | Evaluation of the outcome of out-of-hospital cardiac arrest resuscitation efforts in Denizli, Turkey. | The objective of this study was to evaluate the outcomes and associated factors for short-term success and long-term survival rates of resuscitated non-traumatic out-of-hospital cardiac arrest (OHCAs) in Denizli, Turkey. All non-traumatic OHCA patients from the Emergency Departments of the Pamukkale University and City Hospitals between the dates of January 1, 2004 and March 1, 2005 were included in this study. A successful outcome was defined as the return of spontaneous circulation or breathing, or evidence of a palpable pulse or a measurable blood pressure. Information on post-resuscitation long-term survival up to 9 months also was obtained by telephone. A total of 222 adults experiencing OHCAs were resuscitated. The number of successful outcomes was 85 (38.3%); 25 (11.2%) were discharged alive; and 21 (9.4%) were alive at the 9-month follow-up. The predicted mean arrest time was 11.7 min (95% confidence interval 10.27-13.2). Type of transportation to the Emergency Department (ambulance, 32.1% vs. private vehicle, 44.5%; p = 0.057), place of arrest (home, 32.6% vs. other, 44.0%; p = 0.08), first rhythm at the scene (asystole, 22.9% vs. ventricular fibrillation-pulseless ventricular tachycardia, 48.0%, vs. pulseless electrical activity, 12.5%; p = 0.056), and advanced cardiac life support starting time (the first 8 min, 46.8% vs. later than 8 min, 32.0%; p = 0.025) had an effect on outcome. Intensive public education for diagnosis and appropriate reporting of OHCA, the importance of bystander cardiopulmonary resuscitation, and the use of automated external defibrillators have an impact on the potential to increase the number of survivors. |
7,935 | Gender related differences in patients presenting with acute heart failure. Results from EuroHeart Failure Survey II. | This analysis evaluates the gender differences in patients hospitalised for acute heart failure (AHF) in the EuroHeart Failure Survey II (EHFS).</AbstractText>Of the 3580 patients included in EHFS II, 1384 (39%) were women, mean age 73 years. 2196 (61%) were men, mean age 68 years. Women more frequently had new-onset AHF, hypertension and valvular disease and less frequently coronary heart disease or dilated cardiomyopathy compared with men. Smoking, chronic obstructive pulmonary disease, peripheral arterial disease and renal failure were less common, but diabetes and anaemia significantly more frequent in women. Atrial fibrillation and preserved left ventricular function were more common in women. Men were more often non-compliant with medication. After adjustment for indications and age, there were no significant gender differences in prescription of HF medication. All-cause readmission rate during the one-year follow-up was lower in women. However, the proportion of HF hospitalisation and one-year mortality after discharge (20%) were similar in both genders.</AbstractText>Women frequently present with new-onset AHF. A significant gender difference exists in aetiology, ventricular function and co-morbidities. Women's use of HF medication has improved. These findings emphasize the importance of individualised management and need for more comprehensive recruitment of women in clinical trials.</AbstractText> |
7,936 | Stroke and thromboembolism in atrial fibrillation: a systematic review of stroke risk factors, risk stratification schema and cost effectiveness data. | The risk of stroke in atrial fibrillation (AF) needs to be assessed in each patient to determine the clinical and cost-effectiveness of thromboprophylaxis, with the aim of appropriate use of antithrombotic therapy. To achieve this, stroke risk factors in AF populations need to be identified and stroke risk stratification models have been devised on the basis of these risk factors. In this article, we firstly provide a systematic review of studies examining the attributable stroke risk of various clinical, demographic and echocardiographic patient characteristics in AF populations. Secondly, we performed a systematic review of published stroke risk stratification models, in terms of the results of the review of stroke risk factors and their ability to accurately discriminate between different levels of stroke risk. Thirdly, we review the health economic evidence relating to the cost-effectiveness of anticoagulation and antiplatelet therapy as thromboprophylaxis in AF patients. The studies included in the systematic review of stroke risk factors identified history of stroke or TIA, increasing age, hypertension and structural heart disease (left-ventricular dysfunction or hypertrophy) to be good predictors of stroke risk in AF patients. The evidence regarding diabetes mellitus, gender and other patient characteristics was less consistent. Three stroke risk stratification models were identified that were able to discriminate between different categories of stroke risk to at least 95% accuracy. Few models had addressed the cumulative nature of risk factors where a combination of risk factors would confer a greater risk than either factor alone. In patients at high risk of stroke, anticoagulation is cost effective, but not for those with a low risk of stroke. With the evidence available for stroke risk factors and the various alternative stroke risk stratification models, a review of these models in terms of the evidence on which they are devised and their performance in representative AF populations is important. The appropriate administration of thromboprophylaxis in AF patients would need to balance the risks and benefits of antithrombotic therapy with its cost-effectiveness. |
7,937 | Improved care for patients with congestive heart failure. | Congestive heart failure (CHF) affects 4.9 million people, mostly elderly, in the United States; 550,000 new cases are diagnosed each year. Evidence-based treatment approaches offer opportunities to reduce mortality, complications, and rehospitalization rates.</AbstractText>Seven key components of care tailored to the patient's clinical condition and comorbidities that should be provided to all patients with CHF, in the absence of contraindications or intolerance: (1) left ventricular systolic function assessment, (2) angiotension-converting enzyme-inhibitor or angiotensin receptor blockers at discharge for CHF patients with systolic dysfunction (left ventricular ejection fraction < 40%), (3) anticoagulation at discharge for CHF patients with chronic or recurrent atrial fibrillation, (4) smoking cessation advice and counseling, (5) discharge instructions that address activity level, diet, discharge medications, follow-up appointment, weight monitoring, and what to do if symptoms worsen, (6) influenza immunization (seasonal), and (7) pneumococcal immunization. Hospitals should also consider beta-blocker therapy at discharge for stabilized patients without contraindications.</AbstractText>The 5 Million Lives Campaign's focus on delivering reliable, evidence-based care for patients with CHF is part of an overall strategy to reduce medically induced harm.</AbstractText> |
7,938 | [Case of caffeine poisoning survived by percutaneous cardio-pulmonary support]. | A 17-year-old woman presented to the Emergency Department of our hospital following a suicide attempt. She reported having ingested 340 tablets of caffeine, each of which contained 200mg of caffeine, about 3 hours earlier. Soon after arrival, her blood pressure dropped, and electrocardiography revealed sinus tachycardia and ventricular tachycardia (VT). Subsequently, she developed ventricular fibrillation (VF), and VF was resistant to pharmaceutical interventions and even to cardioversion. Therefore, we performed percutaneous cardiopulmonary support (PCPS). This resulted in disappearance of VF and tachycardia, symptoms of caffeine poisoning, and improvement was observed 16 hours after the start of PCPS. In our case, caffeine poisoning symptoms disappeared without blood purification, after PCPS had stabilized her circulation. Based on our observations in this case, stabilization of the circulation using PCPS in severe caffeine poisoning with VF, a potentially fatal arrhythmia, is a significantly beneficial strategy. |
7,939 | Comparison of 15:1, 15:2, and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation in a canine model of a simulated, witnessed cardiac arrest. | This experimental study compared the effect of compression-to-ventilation (CV) ratios of 15:1, 15:2, and 30:2 on hemodynamics and resuscitation outcome in a canine model of a simulated, witnessed ventricular fibrillation (VF) cardiac arrest.</AbstractText>Thirty healthy dogs, irrespective of species (mean +/- SD, 19.2 +/- 2.2 kg), were used in this study. A VF arrest was induced. The dogs received cardiopulmonary resuscitation (CPR) and were divided into three groups based on the applied CV ratios of 15:1, 15:2, and 30:2. After 1 minute of untreated VF, 4 minutes of basic life support (BLS) was performed. At the end of the 4 minutes, the dogs were defibrillated with an automatic external defibrillator (AED) and advanced cardiac life support (ACLS) efforts were continued for 10 minutes or until restoration of spontaneous circulation (ROSC) was attained, whichever came first.</AbstractText>None of the hemodynamic parameters, and arterial oxygen profiles was significantly different between the three groups during BLS- and ACLS-CPR. Eight dogs (80%) from each group achieved ROSC during BLS and ACLS. The survival rate was not different between the three groups. In the 15:1 and 30:2 groups, the number of compressions delivered over 1 minute were significantly greater than in the 15:2 group (73.1 +/- 8.1 and 69.0 +/- 6.9 to 56.3 +/- 6.8; p < 0.01). The time for ventilation during which compressions were stopped at each minute was significantly lower in the 15:1 and 30:2 groups than in the 15:2 group (15.4 +/- 3.9 and 17.1 +/- 2.7 to 25.2 +/- 2.6 sec/min; p < 0.01).</AbstractText>In a canine model of witnessed VF using a simulated scenario, CPR with three CV ratios, 15:1, 15:2, and 30:2, did not result in any differences in hemodynamics, arterial oxygen profiles, and resuscitation outcome among the three groups. CPR with a CV ratio of 15:1 provided comparable chest compressions and shorter pauses for ventilation between each cycle compared to a CV ratio of 30:2.</AbstractText> |
7,940 | [Antithrombotic therapy in congestive heart failure]. | The risk of thromboembolic complications is increased in patients with advanced chronic heart failure and severe left ventricular dysfunction. Accepted indications for oral anticoagulation include patients with a history of thromboembolism, concomitant atrial fibrillation, or venous, arterial or cardiac thrombosis. In other subgroups, the benefit of chronic anticoagulation has not been proven and existing data from uncontrolled nonrandomized, mostly retrospective studies and prospective, randomized controlled studies are conflicting. This article summarizes the available data on the thromboembolic risk and the potential benefit of antithrombotic therapy and attempts to provide current orientation and recommendations for anticoagulant therapy in patients with chronic heart failure and severe left ventricular dysfunction. |
7,941 | The potential benefits of treatment of sleep apnea in heart failure. | At least half of patients with heart failure (HF) suffer from sleep apnea. Growing evidence suggests that there may be a strong pathophysiological link between chronic HF and sleep apnea due to nocturnal oxygen desaturation and sympathetic activation. It seems that sleep apnea contributes to systolic and diastolic HF, reduced left and right ventricular function, and arrhythmia (e.g. atrial fibrillation, bradycardia, or ventricular ectopy). Therefore, treatment of sleep apnea might alleviate cardiac symptoms and improve cardiac function. Nevertheless, the exact role of long-term treatment of sleep apnea in HF patients remains to be elucidated, as important clinical endpoints (e.g mortality) have been assessed in only a few studies. Heart Fail Monit 2008;5(4):106-11. |
7,942 | Long-term outcome of the atrioventricular node ablation and pacemaker implantation for symptomatic refractory atrial fibrillation. | To investigate long-term outcome and to determine predictors of development of heart failure (HF) in patients with atrioventricular (AV) node ablation and permanent right ventricular pacing because of symptomatic refractory atrial fibrillation (AF).</AbstractText>Atrioventricular node ablation and subsequent permanent pacing is a well-established therapy for patients with AF. Long-term right ventricular pacing may induce HF.</AbstractText>In 121 (45 with previous HF) patients with drug refractory AF, AV node ablation and implantation of a pacemaker was performed. At baseline and after a mean follow-up of 4.3 +/- 3.3 years, New York Heart Association (NYHA) functional class for HF and left ventricular (LV) and atrial diameters were assessed. During and at the end of follow-up, hospitalizations for HF, mortality, and quality of life were assessed using the SF-36 and an AVN-specific questionnaire. No significant changes in NYHA functional class (87 vs. 77% in NYHA I/II at baseline vs. end of follow-up) and LV end diastolic diameter (51 +/- 7 vs. 52 +/- 8 mm) were observed. Left ventricular end systolic diameter decreased (from 37 +/- 9 to 34 +/- 7 mm, P = 0.03) and fractional shortening improved (from 28 +/- 10 to 34 +/- 9, P = 0.02) in all patients and in patients with previous HF, but not in patients without previous HF. Hospitalizations for HF occurred in 24 patients (20%), predominantly those with previous HF. All-cause mortality occurred in 31 (26%) patients. At the end of follow-up, quality of life was comparable with the control group.</AbstractText>Long-term outcome of AV node ablation and permanent pacing is good. Atrioventricular node ablation remains a treatment option for AF.</AbstractText> |
7,943 | Effect of acetate-free biofiltration with a potassium-profiled dialysate on the control of cardiac arrhythmias in patients at risk: a pilot study. | Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia. |
7,944 | Predictors and frequency of conduction disturbances after open-heart surgery. | The risk of developing conduction disturbances after coronary bypass grafting (CABG) or valvular surgery has been well established in previous studies, leading to permanent pacemaker implantation in about 2% to 3% of patients, and in 10% of patients undergoing repeat cardiac surgery. We sought to determine the incidence, features and predictors of conduction disorders in the immediate post-operative period of patients subjected to open-heart surgery, and the need for permanent pacemaker implantation.</AbstractText>We prospectively studied 374 consecutive patients who underwent open-heart surgery in our institution: coronary artery bypass (CABG) (n=128), Mitral valve replacement(MVR)(n=18), aortic valve replacement(AVR) (n=21), MVR and AVR(n=56), repair of ventricular septal defect (VSD) (n=51), repair of tetralogy of Fallot (TOF) (n=57),CABG and valvular surgery (n=6), others (n=37).</AbstractText>Among 374 patients included in our study (mean age 34.46+/-25.68; 146 males), 192 developed new conduction disorders: symptomatic sinus bradycardia in 8%, atrial fibrillation with slow ventricular response (AF) in 4.5%, first-degree atrioventricular block (AVB)in 6.4%, second-degree AVB in 0.3%, third-degree AVB in 7%, new right bundle branch block (RBBB) in 33%, and new left bundle branch block (LBBB) in 2.1%. In 5.6% patients, a permanent pacemaker was implanted, 47.6% of them underwent valvular surgery. In 44.1% of patients the conduction defects occurred in the first 48 hr. after surgery. In CABG group, 29.7% of patients developed new conduction disturbances; the most common of them was symptomatic sinus bradycardia. After valvular surgery 44.2% of patients developed conduction disturbances, of those the most common was atrial fibrillation with slow ventricular response . After VSD and TOF repair, the most common conduction disturbance was new RBBB. Perioperative myocardial infarction (MI) occurred in 1.9% of patients. The occurrence conduction disturbance was compared with patient age, sex, occurrence of perioperative MI, ejection fraction (EF), postoperative use of ss-adernergic receptor blocking agents and digitalis and type of cardiac surgery. By regression analysis there was a correlation between type of surgery and new conduction defects, being significant for CABG and TOF repair. Only the occurrence of perioperative MI was related to PPM implantation.</AbstractText>Irreversible AVB requiring a PPM is an uncommon complication after open-heart surgery. Peri-operative MI is a risk factor.</AbstractText> |
7,945 | Construction and validation of a plunge electrode array for three-dimensional determination of conductivity in the heart. | The heart's response to electrical shock, electrical propagation in sinus rhythm, and the spatiotemporal dynamics of ventricular fibrillation all depend critically on the electrical anisotropy of cardiac tissue. Analysis of the microstructure of the heart predicts that three unique intracellular electrical conductances can be defined at any point in the ventricular wall; however, to date, there has been no experimental confirmation of this concept. We report the design, fabrication, and validation of a novel plunge electrode array capable of addressing this issue. A new technique involving nylon coating of 24G hypodermic needles is performed to achieve nonconductive electrodes that can be combined to give moderate-density multisite intramural measurement of extracellular potential in the heart. Each needle houses 13 silver wires within a total diameter of 0.7 mm, and the combined electrode array gives 137 sites of recording. The ability of the electrode array to accurately assess conductances is validated by mapping the potential field induced by a point current source within baths of saline of varying concentration. A bidomain model of current injection in the heart is then used to test an approximate relationship between the monodomain conductivities measured by the array, and the full set of bidomain conductivities that describe cardiac tissue. |
7,946 | A time-dependent adaptive remeshing for electrical waves of the heart. | In this work, a time-dependent remeshing strategy and a numerical method are presented for the simulation of the action potential propagation of the human heart. The main purpose of these simulations is to accurately predict the depolarization-repolarization front position, which is essential to the understanding of the electrical activity in the myocardium. A bidomain model, which is commonly used for studying electrophysiological waves in the cardiac tissue, will be employed for the numerical simulations. Numerical results are enhanced by the introduction of an anisotropic remeshing strategy. The illustration of the performance and the accuracy of the proposed method are presented using a 2-D analytical solution and a test case with re-entrant waves. |
7,947 | [Long term follow-up results of 199 patients with hypertrophic cardiomyopathy]. | To investigate the associations among clinical characteristics and prognosis in patients with hypertrophic cardiomyopathy (HCM).</AbstractText>Clinical and follow up data of 234 patients with HCM hospitalized in our institute from June, 1999 to March, 2006 were retrospectively analyzed.</AbstractText>A total of 199 out of 234 patients (85%) were followed up for (31.7 +/- 22.6) months. Twenty-one patients died during follow-up, and HCM-related deaths occurred in 19 patients including 11 (57.9%) patients with cardiac arrest, 7 (36.8%) patients with heart failure, 1 patient with stroke. The non-cardiac deaths were 1 accident death and 1 death due to acute pancreatitis. The survival rates of all followed up patients at 1, 2, 3, 4 and 5 years were 96.7%, 94.7%, 94.7%, 93.6% and 89.0%, respectively. Single risk factor analysis indicated that male gender, severe cardiac dysfunction, atrial fibrillation, sustained or non-sustained ventricular tachycardia (SVT or NSVT), left atrial enlargement, left ventricular outflow-track (LVOT) obstruction, family history were correlated with poor prognosis. Multifactor analysis showed SVT or NSVT (RR = 2.234, P < 0.001), NYHA class III - IV (RR = 1.964, P = 0.003) were independent risk factors for death. Among the cardio-cerebral death patients, echocardiography showed 14/19 (73.7%) Maron type III and 1/19 (5.2%) apical myocardial hypertrophy.</AbstractText>A relative benign long-term prognosis was shown in this group of HCM patients. Patients with apical myocardial hypertrophy, SVT or NSVT, NYHA class III - IV were facing increased risk of deaths.</AbstractText> |
7,948 | Role of anticoagulation therapy after pulmonary vein antrum isolation for atrial fibrillation treatment. | Atrial fibrillation (AF) increases the risk of atrioembolic stroke. However, the role of anticoagulation therapy (OAT) in preventing cerebrovascular accidents (CVA) after intracardiac echocardiography-guided pulmonary vein antrum isolation (ICE-PVAI) is still unclear. In the present study, we evaluated the incidence of CVA following the interruption of OAT 3 months after ICE-PVAI.</AbstractText>Between September 2002 and March 2004, 85 consecutive patients (72 men, mean age 62 +/- 7 years) underwent ICE-PVAI for symptomatic drug-refractory AF. Heart disease was present in 61 patients (72%) (left ventricular ejection fraction = 58 +/- 6%, LA diameter 44 +/- 6 mm). Eighty-five consecutive patients who underwent electrical cardioversion (EC) for AF, matched for age, sex and heart disease, served as a control group. After 3 months, OAT was stopped unless one of the following conditions was observed: (i) AF-recurrence; (ii) severe pulmonary vein stenosis; (iii) non-good atrial contractility on transesophageal echocardiography; or (iv) other indications for OAT.</AbstractText>In the study group, OAT was stopped after 3 months in 77 patients (90%) and no CVA occurred during the remaining follow-up (15 +/- 7 months). In the control group, 1 month after EC, OAT was stopped by the referring physician in 29 patients (34%). A stroke occurred in five patients (6%) (P = 0.09; mean P = 0.059) during follow-up. In two of these (2%), the stroke was fatal.</AbstractText>Stopping OAT 3 months after ICE-PVAI seems to be safe in patients without AF recurrences after the first 3 months following ablation. Further randomized-controlled studies are needed to confirm these preliminary data.</AbstractText> |
7,949 | Economic and health consequences of managing bradycardia with dual-chamber compared to single-chamber ventricular pacemakers in Italy. | This study sought to estimate the economic implications of managing bradycardia due to sinoatrial node disease or atrioventricular block with dual compared to single-chamber ventricular pacemakers from an Italian government perspective. Dual-chamber pacemakers lower the risk of developing atrial fibrillation and pacemaker syndrome.</AbstractText>A discrete event simulation of a patient's course for 5 years following pacemaker implantation. Each patient may experience the following: complications, pacemaker syndrome, atrial fibrillation, stroke, or death. Risk functions were based on published data from the Canadian Trial of Physiologic Pacing and Mode Selection Trial in Sinus-Node Dysfunction. Identical patients were simulated after receiving a single or dual-chamber pacemaker. Quality-adjusted life-years (QALYs) and direct medical costs were estimated (2004 Euros). Benefits and costs were discounted at 3%.</AbstractText>The model predicts that implanting the dual-chamber device in 1000 patients will prevent 36 patients from developing atrial fibrillation, 168 from developing severe pacemaker syndrome, but will lead to 13 additional hospitalizations with complications over 5 years. Health benefits are achieved at an incremental cost of 23 euros per patient, and 0.09 QALY, yielding an incremental cost-effectiveness ratio of euro 260 euros/QALY. Sensitivity analysis shows that device replacement rates due to pacemaker syndrome have the biggest impact on the final results.</AbstractText>In the long term, higher initial costs of the dual-chamber device may be offset by a reduction in costs associated with reoperations and atrial fibrillation.</AbstractText> |
7,950 | Long-term follow-up of patients paced in VDD mode for advanced atrioventricular block: a pilot study. | The aim of this pilot study was to estimate the survival trend of patients implanted with VDD pacemakers, and to compare it with the survival curve of the general population of the same region.</AbstractText>Ninety-seven patients (65 male, mean age 78 +/- 6 years) with advanced atrioventricular block referred to our institution were implanted with single-lead VDD pacemakers. All patients were stimulated at the right ventricular apex. At each follow-up visit, a clinical examination was performed and telemetric data collected. In case of death, the family was contacted to record the cause of death. Data on the survival probability of the general population in the Marche Region were obtained from the Italian Institute of Statistics (ISTAT).</AbstractText>During the follow-up (mean 7 +/- 6 years), 17 patients (17.5%) died and eight patients (8.2%) developed atrial fibrillation. Atrioventricular synchrony was 97 +/- 3% in the overall patient population, excluding patients with atrial fibrillation. Only one patient was upgraded to DDD pacing owing to symptomatic loss of atrial sensing; after the upgrading procedure symptoms disappeared. During the follow-up period, 19 pacemakers were replaced for end of life of the battery. Patients who died during follow-up were aged 80 +/- 7 years at implantation and 85 +/- 6 years at death. The comparison between the trend line simulating the patient survival probability of the studied VDD population, and the survival probability of males in the Marche Region did not show any significant difference.</AbstractText>In patients chronically paced with a single-lead VDD system, survival probability seems to be similar to that of the general population.</AbstractText> |
7,951 | [RF ablation of longstanding persistent atrial fibrillation in patient with familial dilated cardiomyopathy]. | A vicious circle of interactions between dilated cardiomyopathy and longstanding persistent AF/AFL may cause symptoms of advanced congestive heart failure. In a 31-year-old patient with diagnosis of familial dilated cardiomyopathy and permanent AF lasting for five years, gradually decreased left ventricular ejection fraction (LVEF) and increased diameter of heart chambers - left ventricular diastolic dimension (LVdD) 7.7 cm, left atrium (LA) 5.4 cm, and LVEF 15% were noted. Pharmacological treatment was ineffective Successful RF ablation of AF/AFL substrate (CTI block, PVs isolation, CFAE ablation, roof and MIG line, CS applications) reversed symptoms of significant heart remodeling (LVdD 5.9 cm, LA 4.3 cm, LVEF 50%). |
7,952 | Diastolic dysfunction and atrial fibrillation. | Isolated diastolic heart failure (DHF) is defined as heart failure with preserved left ventricular (LV) systolic function in the absence of valve disease. DHF is a clinical diagnosis confirmed by echocardiography and is presumed to be due to diastolic dysfunction (DD). DD is characterized by abnormalities in relaxation and/or distensibility (restriction) of the left ventricle (LV). DHF accounts for 30% to 50% of patients with heart failure and is an independent predictor of atrial fibrillation (AF) in the elderly.</AbstractText>This paper will describe the diagnosis of DD in both sinus rhythm and AF as well report on agents used in the treatment of DHF and prevention of AF in DHF. DIAGNOSIS IN SINUS RHYTHM: Early DD is identified by Doppler determined mitral inflow measurements: The ratio of the peak velocity of the early filling (E) wave to the atrial contraction (A) wave, E/A is <1, the deceleration time (DT) is slow (>240 ms), the isovolumic relaxation period (IRP) is prolonged (>110 ms). In Moderate DD, the LV stiffens with elevated left atrial pressure resulting in "pseudonormal" filling pattern with E/A ratio >1. This is unmasked by pulmonary vein measurements with the systolic forward flow (S) being less than (approximately 50%) diastolic forward flow wave (D). Retrograde flow wave (A (R)) is increased >0.25 m/s. As the LV stiffens, restrictive features develop resulting in rapid early filling with E/A ratio >2, shortened DT <150 ms and IRP <60 ms. The A (R) wave is increased in amplitude >0.35 m/s and duration >30 ms. Early diastolic filling reflected by tissue Doppler determination of mitral annulus motion velocity (E') is reduced in DD. The E/E' ratio correlates well with filling pressures. DIAGNOSIS IN AF: Atrial contraction is absent and therefore measurements independent of atrial influence such as DT, IRP, E/E' ratio and S wave are used. THERAPY FOR DHF AND AF PREVENTION: While not well established, Treatment with ACE-inhibitors, angiotensin receptor blockers (ARBs) and aldosterone antagonists have shown objective improvement in DHF and ARBs have been found to decrease the incidence of AF. Candesartan decreases the incidence of AF in patients with symptomatic heart failure and preserved LV systolic function. There are ongoing studies of Irbesartan and spironolactone to evaluate their effect on DHF treatment.</AbstractText>Diagnosis of DD is made by echocardiography in patients with sinus rhythm or in patients with AF. Randomized controlled trials in patients with DHF are under way. The treatment of DHF and AF prevention will continue to evolve.</AbstractText> |
7,953 | Endothelin system and atrial fibrillation post-cardiac surgery. | We investigated the relation between the endothelin system and atrial fibrillation.</AbstractText>Endothelin has been implicated in the pathophysiology of atrial fibrillation, but the exact role of A- and B-receptors is unknown.</AbstractText>We obtained right atrial biopsies from patients in sinus rhythm and preserved left ventricular function, undergoing off-pump coronary artery bypass grafting. The expression of endothelin, A- and B-receptors was measured using real time reverse-transcribed polymerase chain reaction.</AbstractText>We studied 52 patients (45 male, mean age 66+/-1 years, mean ejection fraction 52+/-1%). During a 5-day post-operative period, persistent atrial fibrillation occurred in 15 patients (28.8%). Endothelin mRNA expression was comparable in patients who subsequently developed atrial fibrillation and in those maintaining sinus rhythm. However, the former group displayed down-regulation of endothelin A- (by approximately 60%, p=0.0059) and of B-receptors (by approximately 40%, p=0.0084). The decreased endothelin A-receptor expression could predict atrial fibrillation occurrence (Wilks lambda=0.86, F=6.16, p=0.017).</AbstractText>Decreased endothelin A- and B-receptor expression is associated with atrial fibrillation after bypass surgery.</AbstractText> |
7,954 | The new world of cardiac interventions: a brief review of the recent advances in non-coronary percutaneous interventions. | Advances in cardiovascular interventional techniques have allowed percutaneous treatment of conditions that either previously required open operations or have not been amenable to treatment. Conditions such as atrial and ventricular septal defects and patent foramen ovale are now amenable to percutaneous closure using implantable devices. A number of strategies have evolved to reduce the risk of stroke such as percutaneous occlusion of the left atrial appendage for patients in atrial fibrillation. Valvular heart disease and complications of its repair are approachable via the percutaneous route. Percutaneous pulmonary and aortic valve replacements have been performed in humans. There are evolving techniques for repair of the mitral valve and of prosthetic paravalvular leaks using devices such as the Amplatzer septal occluder to repair the defects without the need for repeat open heart surgery. Hypertrophic cardiomyopathy with left ventricular outflow tract obstruction can now be approached using alcohol septal ablation with results comparable to the surgical technique. These advances have occurred as a result of improvement in the design of the devices used as well as a better understanding of the pathophysiology of conditions. Many of these techniques are in evolution and in this paper we review some of the recent developments in this dynamic area of interventional cardiology. |
7,955 | [The system of hemostasis in patients with atrial fibrillation: markers of left auricular thrombosis]. | Thrombosis of the left atrial appendage (LAA) is considered to be main cause of thromboembolic complications of atrial fibrillation (AF). Aim of this work was to study parameters of the hemostasis system in patients with AF in dependence on the presence of thrombus in the LAA. We examined 92 patients (58 men and 34 women) who at hospital admission had AF attack which lasted more than 48 hours. In patients with thrombus in the LAA according to data of transesophageal echocardiography differed magnitude of mean pulmonary artery pressure (odds ratio [OR] 1.053 95% confidence interval [CI] 1.007 to 1.102, p=0.024), diameter of left ventricular (LV) outflow tract (OR 7.711 95% CI 1.291 to 46.029, p=0.025), LV ejection fraction less than 40% (OR 0.286 95% CI 0.081 to 1.008, p=0.051), levels of type 1 plasminogen activator inhibitor-PAI-1 (OR 0.641 95% CI 0.422 to 0.974, p=0.037), and D-dimer (OR 1.003, 95% CI 1.000 to 1.006, p=0.046). Factors independently related to the presence of thrombus in LAA turned out only levels of PAI-1 (OR 0.51, 95% CI 0.276 to 0.936, p=0.03) and D-dimer (OR 1.01, 95% CI 1.001 to 1.014, p=0.026). Thus depletion of the system of fibrinolysis can lead to thrombus formation in the LAA and increase risk of development of thromboembolic complications. |
7,956 | [Clinical efficacy of permanent cardiac pacing in patients with bradysystolic forms of disturbances of cardiac rhythm and conduction]. | From 1996 to 2002 primary implantations of pacing systems because of bradysystolic disturbances of cardiac rhythm and conduction had been carried out in 311 patients. Indications were disturbances of atrioventricular conduction in 168 and sick sinus syndrome in 143 patients. According to type of permanent pacing patients were divided into 3 groups: with single-chamber ventricular on demand pacing (VVI, n=215), with single-chamber atrial pacing (AAI, n=39), and with dual-chamber pacing (DDD, n=57). As characteristics illustrating long term clinical results of permanent pacing we used development of the pacemaker syndrome; development of permanent atrial fibrillation; risk of thromboembolic complications and strokes; progression of heart failure; total, cardiovascular mortality and their structure; 7 year survival. |
7,957 | [Complications of stress-echocardiography used for diagnosis of ischemic heart disease]. | Prevalence of minor and major complications, side effects of stress echocardiography (stress-echoCG) was studied in a group of 1359 patients with suspected ischemic heart disease (IHD). Dipyridamole/atropine test was carried out in 184, dobutamine/atropine test - in 231, transesophageal atrial pacing (TEAP) - in 154, veloergometry (VEM) in half sitting position - in 122, and combination stress-echoCG - in 668 patients (dipyridamole/TEAP, n=151; dipyridamole/dobutamine, n=162; dipyridamole/paired TAP, n=112). We classified ventricular and supraventricular extrasystoles, head ache, nausea, muscular tremor as side effects, short paroxysms (less than 2 min) of hemodynamically insignificant supraventricular and ventricular tachycardia - as minor complications, and development of acute coronary syndrome, ventricular fibrillation - as major complications. Most frequent side effects during stress-echoCG were rare ventricular extrasystoles (26.0% during dobutamine, 18.9% during VEM test), and head ache (16,7% in dipyridamole tests). Major complications occurred in 2 cases (0,147%). One patient during standard dipyridamole test developed acute coronary syndrome requiring urgent coronary angiography and angioplasty of the right coronary artery. Another patient after administration of 0.25 ml of 0.1% atropine solution at the background of dobutamine infusion (40 mcg/kg/min) had ventricular fibrillation requiring resuscitative measures. Although stress-echoCG in general is a safe and highly informative method of diagnosis of IHD it can be accompanied with side effects during action of stress-agents, minor and major complications during conduction of tests. This dictates necessity of obtainment of compulsory informed consent from patients. |
7,958 | [Metalloproteinase activity of the blood in patients with arterial hypertension with paroxysmal form of atrial fibrillation]. | Aim of the study was to investigate interrelationship between serum markers of myocardial fibrosis: matrix metalloproteinase -1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and parameters of echocardiography in patients with arterial hypertension (AH) and paroxysmal form of atrial fibrillation (n=39). We revealed positive correlation of levels of TIMP-1 with thickness of interventricular septum in diastole (r=0,47, p=0,02), peak velocity of late filling of the right ventricle (r=0,46, p=0,01), and negative relation between MMP-1 levels and degree of mitral and tricuspid regurgitation (r=0,43, p=0,005 and r=0,38, p=0,04, respectively). In the group of patients with increased left ventricular myocardial mass index (LVMMI) TIMP-1 level was significantly higher than in patients with normal LVMMI (p < 0,05). In the group combining patients with concentric and eccentric LV hypertrophy TIMP-1 level was significantly higher than in the group combining patients with LV concentric remodeling and normal geometry (p < 0,05). No correlations were revealed between MMP-1 and TIMP-1 levels and parameters of diastolic dysfunction. In patients with AH increase of serum concentrations of TIMP-1 was associated with increased thickness of interventricular septum, increase of LVMMI, and with prognostically unfavorable types of LV remodeling. |
7,959 | [Autotransplantation of the heart as the method of treatment of congestive heart failure]. | Congestive heart failure with preserved or moderately lowered left ventricular pump function in some patients is caused by mitral regurgitation. Its consequences are left atrial dilation, pulmonary hypertension, tricuspid regurgitation, thromboembolic complications, disturbances of rhythm with elevated risk of sudden death. As efficacy of drug treatment and electroimpulse therapy is small surgery is the method of choice and one of alternatives - autotransplantation of the heart. Here we present a successful experience of application of this technique in a patient with moderately lowered left ventricular function, extreme degree of mitral and tricuspid regurgitation, atriomegaly, atrial fibrillation, and pronounced manifestations of congestive heart failure. |
7,960 | [Arrhythmias in pregnancy: etiology and perinatal outcomes]. | We analysed 132 case forms of pregnant women who delivered in a special maternity hospital for patients with cardiovascular diseases. Complex disorders of heart rhythm (paroxysmal supraventricular tachycardia, atrial fibrillation, frequent ventricular extrasystoles, and II - III degree atrioventricular block) were revealed in 64 (48.5%) of women. Etiological factors of these arrhythmias and blocks in 50% of cases were organic and functional derangements of cardiovascular system. In other 50% of cases causes of heart rhythm disorders were not established and they were classified as idiopathic. Perinatal outcomes in women with arrhythmias and blocks were worse than in women without this pathology. They appeared as intrauterine retardation of fetus development and various derangements of central nervous system in newborns. |
7,961 | [The role of omega-3 fatty acids from fish in prevention of cardiovascular diseases]. | Fish and fish oil are rich sources of omega-3 fatty acids--essential polyunsaturated fatty acids. These acids in doses of 1 g per day have been shown to significantly reduce the all-cause mortality in post myocardial infarction (MI) patients and the risk for sudden death caused by cardiac arrhythmias. One of the recently most studied mechanisms that may contribute to this benefits of omega-3 fatty acids is their anti-arrhythmic effect. Namely, these acids influence membrane ion channels, increase ventricular fibrillation threshold and increase heart rate variability. Although the data concerning primary prevention is less straightforward than the data relating secondary prevention, it seems that the use of omega-3 fatty acids in primary prevention might be justified as well. In higher doses (2 to 4 g per day) they are used to treat hypertriglyceridemia. Potential mechanisms by which omega-3 fatty acids may reduce risk for cardiovascular disease include also antithrombotic (they decrease platelet aggregation/reactivity, reduce plasma viscosity, enhance fibrinolysis) and anti-inflammatory effects (e.g. they decrease IL-6, MCP-1, TNF), improving vascular endothelial cell function (e.g. they increase availability of nitric oxide), reducing expression of endothelial cells adhesion molecules, inhibiting smooth muscle cells migration and proliferation, and reducing blood pressure. Based upon clinical studies the use of omega-3 fatty acids should be considered today at least as a part of comprehensive secondary prevention strategy in post-MI patients. It has been also shown that adding highly concentrated omega-3 fatty acids to standard treatment in the secondary prevention of MI is cost effective versus standard treatment alone. Particularly important is that there are no significant drug interactions with omega-3 fatty acids. |
7,962 | Sudden cardiac death caused by migration of a TrapEase inferior vena cava filter: case report and review of the literature. | A 43-year-old female presented with sudden onset of palpitations, chest pain, and shortness of breath associated with hypoxemia. A helical computed tomography (CT) scan of the chest revealed a large saddle pulmonary embolism. Intravenous tPA relieved the shortness of breath and improved the hypoxemia. Inferior vena cava (IVC) filter (TrapEase, Cordis Corp., Miami, FL, USA) was placed. On day 6 of her hospitalization, she went into cardiopulmonary arrest while walking back from the rest room. The patient died despite a prolonged attempt at cardiopulmonary resuscitation. At that time, ventricular tachycardia and then ventricular fibrillation were recorded. Autopsy of the heart showed the IVC filter entrapped within the tricuspid valve.</AbstractText>The incidence of IVC filter migration ranges from 0.3 to 6% with rare migration to the heart or lung (0.1-1.25%). Sudden cardiac death from migration of IVC filter is extremely rare. We report the first case of sudden cardiac death caused by migration of the TrapEase filter to the heart. There are two reports in the literature of death from migrating Greenfield and Antheor filters.</AbstractText>An IVC filter migration to the heart, although rare, can cause serious arrhythmia and sudden cardiac death.</AbstractText>Copyright (c) 2008 Wiley Periodicals, Inc.</CopyrightInformation> |
7,963 | Haemodynamic impact of the left ventricular pacing site during graded ischaemia in an open-chest pig model. | In post-operative setting after cardiac surgery, the choice of the optimal ventricular pacing site remains an issue, particularly in patients with ischaemic cardiomyopathy. We aimed to investigate the impact of the left ventricular (LV) pacing site in an animal model of incremental myocardial ischaemia.</AbstractText>Three epicardial LV pacing leads were implanted in 10 pigs [LV1 in the territory of the left anterior descending (LAD) artery, LV2 in the lateral border of this territory, LV3 in an anatomically opposed position]. A two-dimensional strain echocardiogram was performed at baseline and during two levels of incremental ischaemia, corresponding to 30 and 70% reduction of coronary flow in the LAD, during spontaneous sinus rhythm (SR) and during LV1, LV2, LV3, and multi-LV (LV1 + LV2 + LV3) pacing. At baseline (n = 10), LV + dP/dt(max) was decreased (P < 0.01) during LV1, LV2, LV3, and multi-LV pacing compared with SR. At first level of ischaemia (n = 7; 3 animals died from ventricular fibrillation), LV1 pacing (ischaemic area) induced a significant decrease in LV + dP/dt(max) compared with SR, LV2, LV3, and multi-LV pacing (P < 0.05). At second level of ischaemia (n = 6), LV1 pacing induced a significant decrease in LV + dP/dt(max) associated with an increase in the extent of myocardium with echocardiographic post-systolic shortening compared with SR, LV2, LV3, or multi-LV pacing (P < 0.05). In contrast, multi-LV pacing induced a significant haemodynamic improvement compared with SR, LV1, LV2, and LV3 (P < 0.05).</AbstractText>Pacing within an ischaemic area has detrimental impact on acute global and regional LV function. More studies are needed to assess the impact of multi-LV pacing in chronic ischaemic conditions.</AbstractText> |
7,964 | Risk stratification after myocardial infarction: a new method of determining the neural component of the baroreflex is potentially more discriminative in distinguishing patients at high and low risk for arrhythmias. | We hypothesize that the neural component (NC) of the baroreflex sensitivity (BRS) is a better risk stratifier for ventricular tachycardia/fibrillation (VT/VF) than conventional BRS itself, because it is both independent of vessel wall stiffness and can be measured non-invasively.</AbstractText>NC was determined by correlating spontaneous carotid artery diameter variations with R-R interval variations using spectral analyses. In consecutive outpatient populations with chronic coronary artery disease the ability of the NC to distinguish post-myocardial infarction (MI) patients at risk for VT/VF (post-MI(HIGH RISK)) from post-MI less prone to arrhythmias (post-MI(LOW RISK)) was compared with the pressure-derived BRS(phenyl) and BRS(spectral) method. Ninety-six patients, i.e. 28 post-MI(LOW RISK), 28 post-MI(HIGH RISK) [a LVEF(left ventricular ejection fraction) <30% and/or history of VT/VF] and 40 healthy controls were enrolled. With NC, rather than with BRS methods, median values for post-MI(HIGH RISK) were smaller than for post-MI(LOW RISK) patients (NC, P = 0.03; BRS(spectral), P = 0.35; BRS(phenyl), P = 0.63). Variability of R-R interval (LF = 0.04-0.15 Hz) was significantly larger in the control group than in the post-MI(HIGH RISK) and post-MI(LOW RISK) group (P < 0.01 and P < 0.01). To separate post-MI(HIGH RISK) from post-MI(LOW RISK) patients, a linear combination of age and the logarithm of the NC measurement was constructed as a risk index. By optimizing the intercept of this line, an optimal sensitivity and specificity pair was determined. The sum of optimal specificity and sensitivity was higher for NC (155) than for BRS(spectral) (133) and BRS(phenyl) method (132). With all methods, values for post-MI patients were significantly smaller than for controls.</AbstractText>NC may be superior to conventional BRS measures in identifying post-MI patients at high risk for VT/VF.</AbstractText> |
7,965 | Atrial fibrillation in left ventricular noncompaction with and without neuromuscular disorders is associated with a poor prognosis. | The study in patients with left ventricular hypertrabeculation/noncompaction (LVHT) aimed to compare patients with and without atrial fibrillation (AF) regarding prevalence of neuromuscular disorders (NMD), cardiac symptoms, electrocardiographic (ECG) findings, left ventricular function, location and extension of LVHT and mortality.</AbstractText>LVHT was diagnosed in 102 patients (30 female, age 53+/-16 years) between June 1995 and November 2006. A specific NMD was diagnosed in 21, a NMD of unknown etiology in 47, the neurologic investigation was normal in 14, and 20 patients refused. The 15 patients with AF were older (65 versus 51 years, p<0.01), suffered more often from exertional dyspnoea (100 versus 62%, p<0.01), diabetes mellitus (33 versus 12%, p<0.05) and heart failure (100 versus 57%, p<0.01) than patients without AF. The prevalence of NMD was slightly higher in patients with than without AF (87 versus 82%, p=NS). AF patients had more frequent ECG abnormalities (2.3 versus 1.4, p<0.01), valvular abnormalities (93 versus 48%, p<0.01), lateral wall LVHT (87 versus 37%, p<0.01), more extensive LVHT (2.1 versus 1.5 ventricular parts, p<0.05), a worse left ventricular fractional shortening (14 versus 25%, p<0.01) and higher mortality during 3.8 years.</AbstractText>LVHT-patients with AF deserve special care because they have a worse prognosis than LVHT-patients without AF.</AbstractText> |
7,966 | [Health effects of occupational exposure to static magnetic fields used in magnetic resonance imaging: a review]. | Magnetic resonance imaging is an established diagnostic tool involving exposure to static magnetic fields (SMF) of patients and health personnel (radiology technicians, radiologists, anaesthetists, surgeons, maintenance staff). Occupational exposure to SMF will be governed by the rules of European Union Directive 2004/40/EC covering health and safety requirements regarding the exposure of workers to risks from electromagnetic radiations, which must be incorporated into national law by each member state by 30 April 2008. It applies to all employment sectors and addresses short-term adverse health effects on workers, but excludes possible long-term effects. This study aims to critically review the recent literature on the topic so as to propose guidelines on the need to provide information and training of workers and appropriate health surveillance.</AbstractText>To identify the studies published after the review by the World Health Organization (WHO) in the series Environmental Health Criteria, a search was carried out on Medline. The strategy defined for searching studies was based on the following MeSH terms, which comprehensively addressed the problem: (i) Magnetic Resonance Imaging, (ii) Electromagnetic Fields, (iii) Electromagnetic Fields/adverse effects, (iv) Occupational Health. These terms were used to create appropriate search links to identify the studies according to the following criteria: (i) English language, (ii) inclusion of review, case-control and cohort study, controlled trials, (iii) abstract availability (iv) human effects, mechanism of action, pathophysiology or in vitro studies, (v) studies published after 1 January 2004 not considered in the WHO review. Twenty-eight studies were available as full-text.</AbstractText>Although studies carried out at cellular level are valuable in investigating mechanisms of interaction, they did not show any specific effect as a consequence of exposure to SMF. Experimental studies carried out on volunteers showed that short-term exposure to SMF induces a variety of acute effects: (i) vertigo, nausea and a metallic taste in the mouth occur during body or head movement with SMF in T range and may result in a possible negative influence on the performance of workers during critical procedures, (ii) changes in blood pressure and heart rate within the range of physiological variability occur for exposures to SMF up to 8 T (iii) induction of ectopic heart beats and increased likelihood of reversible arrhythmia (possibly leading to ventricular fibrillation) may occur in susceptible workers) (iv) a decrease of working memory and eye-hand coordination are dose-dependent for exposures to 1.5-3 T SMF and may affect the performance of workers executing intricate procedures. The limitations of the available studies, however, do not allow any firm conclusions to be drawn about the effects of SMF on the described endpoints.</AbstractText>According to Directive 2004/40/EC, the employer must ensure that workers exposed to risks from electromagnetic fields receive all necessary information about the potential risks and that appropriate health surveillance is carried out to prevent any adverse health effects. According to the reported data it will not be easy to proved information and training and the appropriate health surveillance for the exposed workers. In fact, information and training activities might be influenced by the uncertainties resulting from the available evidence, since ability will be needed to find a balance between few certainties and several doubts, while the same uncertainties might reflect on the preventive and periodical examinations aiming at preventing short-term adverse health effects.</AbstractText> |
7,967 | [In-hospital prognosis of right ventricular myocardial infarction]. | To identify prognostic risk factors for in-hospital outcome of right ventricular myocardial infarction (RVI).</AbstractText>A retrospective study of 20 patients admitted with acute myocardial infarction with a RVI defined by ST segment elevation > or = 1 mm in V3R and V4R leads.</AbstractText>The mean age was 62 years. RVI was associated with an inferior myocardial infarction in 18 patients. Half of the patients had hemodynamic complication on admission (cardiogenic shock in 4 cases, right ventricular failure in 6 cases) and third degree atrio-ventricular block was present in 5 patients. Sixteen patients (80%) received thrombolysis and 3 went to an emergency angioplasty. The in-hospital mortality was 25% caused by a cardiogenic shock in 4 patients and a ventricular fibrillation in 1 patient. Statistic analysis showed that cardiogenic shock on admission, the absence of thrombolytic therapy and the low ejection fraction of the left ventricle were associated with a high in-hospital mortality (p = 0.004, p = 0.03, p = 0.03 respectively).</AbstractText>In-hospital outcome of RVI is characterized by hemodynamic complications leading to a high incidence of mortality. Thus RVI must be diagnosed quickly and maximal therapeutic efforts must be done to procure the opening of the occluded coronary artery.</AbstractText> |
7,968 | Thiazolidinedione drugs block cardiac KATP channels and may increase propensity for ischaemic ventricular fibrillation in pigs. | <AbstractText Label="AIMS/HYPOTHESIS" NlmCategory="OBJECTIVE">Opening of ATP-sensitive potassium (K(ATP)) channels during myocardial ischaemia shortens action potential duration and is believed to be an adaptive, energy-sparing response. Thiazolidinedione drugs block K(ATP) channels in non-cardiac cells in vitro. This study determined whether thiazolidinedione drugs block cardiac K(ATP) channels in vivo.</AbstractText>Experiments in 68 anaesthetised pigs determined: (1) effects of inert vehicle, troglitazone (10 mg/kg i.v.) or rosiglitazone (0.1 or 1.0 mg/kg i.v.) on epicardial monophasic action potential (MAP) during 90 min low-flow ischaemia; (2) effects of troglitazone, rosiglitazone or pioglitazone (1 mg/kg i.v.) on response of MAP to intracoronary infusion of a K(ATP) channel opener, levcromakalim; and (3) effects of inert vehicle, rosiglitazone (1 mg/kg i.v.) or the sarcolemmal K(ATP) blocker HMR-1098 on time to onset of ventricular fibrillation following complete coronary occlusion.</AbstractText>With vehicle, epicardial MAP shortened by 44+/-9 ms during ischaemia. This effect was attenuated to 12+/-8 ms with troglitazone and 6+/-6 ms with rosiglitazone (p<0.01 for both vs vehicle), suggesting K(ATP) blockade. Intracoronary levcromakalim shortened MAP by 38+/-10 ms, an effect attenuated to 12+/-8, 13+/-4 and 9+/-5 ms during co-treatment with troglitazone, rosiglitazone or pioglitazone (p<0.05 for each), confirming K(ATP) blockade. During coronary occlusion, median time to ventricular fibrillation was 29 min in pigs treated with vehicle and 6 min in pigs treated with rosiglitazone or HMR-1098 (p<0.05 for both vs vehicle), indicating that K(ATP) blockade promotes ischaemic ventricular fibrillation in this model.</AbstractText><AbstractText Label="CONCLUSIONS/INTERPRETATION" NlmCategory="CONCLUSIONS">Thiazolidinedione drugs block cardiac K(ATP) channels at clinically relevant doses and promote onset of ventricular fibrillation during severe ischaemia.</AbstractText> |
7,969 | Public health impact of full implementation of therapeutic hypothermia after cardiac arrest. | Induced hypothermia improves outcomes in patients resuscitated successfully after cardiac arrest due to ventricular fibrillation. However, a minority of US physicians currently use the therapy. The aim of this study was to project the public health impact of implementing hypothermia in all eligible US out-of-hospital cardiac arrest (OHCA) survivors.</AbstractText>The number of OHCA patients expected to have a good outcome after hypothermia was calculated using a linear model. Literature-derived input variables included OHCA incidence rates and US 2000 census data, percent with return to spontaneous circulation (ROSC), percent eligible for hypothermia, and the expected benefit from hypothermia. Sensitivity analyses were performed to calculate a plausible range around the reference case.</AbstractText>An additional 2298 US patients per year are expected to have a good neurological outcome if US physicians implement hypothermia fully in comatose survivors of OHCA. The two-way sensitivity analyses found that this number ranged from 766 to 5171 patients. This model is similarly sensitive to varying the incidence of OHCA, percent with ROSC, percent of patients eligible for hypothermia, and the number needed to treat.</AbstractText>If US physicians adopt therapeutic hypothermia fully in eligible patients with OHCA, 2298 additional patients per year would be expected to achieve a good neurological outcome, a substantial public health impact. Barriers to adoption should be researched and addressed to increase acceptance and use by US physicians.</AbstractText> |
7,970 | The intrinsic resistance of female hearts to an ischemic insult is abrogated in primary cardiac hypertrophy. | Important sex differences in cardiovascular disease outcomes exist, including conditions of hypertrophic cardiomyopathy and cardiac ischemia. Studies of sex differences in the extent to which load-independent (primary) hypertrophy modulates the response to ischemia-reperfusion (I/R) damage have not been characterized. We have previously described a model of primary genetic cardiac hypertrophy, the hypertrophic heart rat (HHR). In this study the sex differences in HHR cardiac function and responses to I/R [compared to control normal heart rat (NHR)] were investigated ex vivo. The ventricular weight index was markedly increased in HHR female (7.82 +/- 0.49 vs. 4.80 +/- 0.10 mg/g; P < 0.05) and male (5.76 +/- 0.22 vs. 4.62 +/- 0.07 mg/g; P < 0.05) hearts. Female hearts of both strains exhibited a reduced basal contractility compared with strain-matched males [maximum first derivative of pressure (dP/dt(max)): NHR, 4,036 +/- 171 vs. 4,258 +/- 152 mmHg/s; and HHR, 3,974 +/- 160 vs. 4,540 +/- 259 mmHg/s; P < 0.05]. HHR hearts were more susceptible to I/R (I = 25 min, and R = 30 min) injury than NHR hearts (decreased functional recovery, and increased lactate dehydrogenase efflux). Female NHR hearts exhibited a significantly greater recovery (dP/dt(max)) post-I/R relative to male NHR (95.0 +/- 12.2% vs. 60.5 +/- 9.4%), a resistance to postischemic dysfunction not evident in female HHR (29.0 +/- 5.6% vs. 25.9 +/- 6.3%). Ventricular fibrillation was suppressed, and expression levels of Akt and ERK1/2 were selectively elevated in female NHR hearts. Thus the occurrence of load-independent primary cardiac hypertrophy undermines the intrinsic resistance of female hearts to I/R insult, with the observed abrogation of endogenous cardioprotective signaling pathways consistent with a potential mechanistic role in this loss of protection. |
7,971 | Prediction of unexpected sudden death among healthy dogs by a novel marker of autonomic neural activity. | Unexpected sudden death among apparently healthy individuals remains a daunting problem. We have previously shown that autonomic modulation of cardiac arrhythmias and autonomic markers, such as baroreflex sensitivity (BRS) and heart rate variability (HRV), carry predictive power after myocardial infarction.</AbstractText>We tested the hypothesis that a parameter combining BRS and HRV could predict risk for ventricular fibrillation (VF) during a first ischemic episode in otherwise healthy dogs.</AbstractText>In 43 fully instrumented dogs, BRS and frequency domain analysis of HRV were determined, as well as the occurrence (n = 10, high-risk) or absence (n = 33, low-risk) of VF during 2 minutes of myocardial ischemia superimposed on submaximal exercise. TARVA (Tonic and Reflex Vagal Activity), expressed in units, is the parameter resulting from the multiplication of BRS by HF/LF (an index of tonic vagal activity).</AbstractText>High-risk dogs had markedly lower TARVA values, reflecting lower cardiac vagal activity, than low-risk animals (12 +/- 5 versus 56 +/- 43 units, P < .001). The area under the receiver-operator characteristic curve for TARVA was 0.96 (95% confidence interval 0.86 to 0.99); its optimal cutoff had a 100% sensitivity and a 88% specificity with positive and negative predictive values of 71% and 100%, respectively.</AbstractText>Differences in cardiac autonomic activity, present in healthy dogs, allow prediction of arrhythmic risk during a first ischemic episode. Increased risk is associated with reduced vagal activity. If confirmed in humans, this finding would open the way to the identification of those apparently healthy subjects at risk for sudden cardiac death during their first episode of myocardial ischemia.</AbstractText> |
7,972 | Prophylactic implantation of cardioverter-defibrillator in patients with severe cardiac amyloidosis and high risk for sudden cardiac death. | Cardiac light-chain amyloidosis carries a high risk for death predominantly from progressive cardiomyopathy or sudden death (SCD). Independent risk factors for SCD are syncope and complex nonsustained ventricular arrhythmias.</AbstractText>The purpose of this study was to test whether prophylactic placement of an implantable cardioverter-defibrillator (ICD) reduces SCD in patients with cardiac amyloidosis.</AbstractText>Nineteen patients with histologically proven cardiac amyloidosis and a history of syncope and/or ventricular extra beats (Lown grade IVa or higher) received an ICD.</AbstractText>During a mean follow-up of 811 +/- 151 days, two patients with sustained ventricular tachyarrhythmias were successfully treated by the ICD. Two patients underwent heart transplantation, and seven patients died due to electromechanical dissociation (n = 6) or glioblastoma (n = 1). Nonsurvivors more often showed progression of left ventricular wall thickness, low-voltage pattern, ventricular arrhythmias (Lown grade IVa or higher), and higher N-terminal pro-brain natriuretic peptide levels than did survivors. Bradycardias requiring ventricular pacing (VVI 40/min <1%, DDD 60/min 6% +/- 1%) occurred only rarely.</AbstractText>Patients with cardiac amyloidosis predominantly die as a result of electromechanical dissociation and other diagnoses not amenable to ICD therapy. Selected patients with cardiac amyloidosis may benefit from ICD placement. Better predictors of arrhythmia-associated SCD and randomized trials are required to elucidate the impact of ICD placement in high-risk patients with cardiac amyloidosis.</AbstractText> |
7,973 | Endovascular treatment of an intramural aortic haematoma following cardiopulmonary resuscitation for myocardial ischemia with ventricular fibrillation. | Cardiopulmonary resuscitation by manual cardiac compression can restore cardiocirculatory function but can also injure patients. Commonly reported are skeletal fractures of the rips and sternum, while injuries to the large thoracic vessels will frequently be lethal. We report the case of a 57-year-old male patient with sudden cardiac arrest because of myocardial ischemia with ventricular fibrillation, successful cardiopulmonary resuscitation, associated with an intramural haematoma (IMH) of the descending thoracic aorta treated by endovascular aortic repair. Secondary coronary angiography revealed a severe three vessel coronary disease with an occlusion of the proximal anterior descending branch and a subtotal stenosis of the first segmental branch of the left coronary artery (LCA) and a high-grade stenosis of the posterolateral segmental branch of the circumflex left coronary artery. Stenotic segments of coronary arteries were treated successfully by implantation of three drug-eluting stents followed by dual antiplatelet therapy. The patients recovered almost completely and was discharged for further rehabilitation after 3 weeks. |
7,974 | Non-selective cyclooxygenase inhibition before periodic acceleration (pGz) cardiopulmonary resuscitation (CPR) in a porcine model of ventricular fibrillation. | Whole body periodic acceleration (pGz) along the spinal axis is a novel method of cardiopulmonary resuscitation (CPR). Oscillatory motion of the supine body in a horizontal fashion provides ventilation and blood flow to vital organs during cardiac arrest and pulsatile shear stress to the vascular endothelium. We previously showed in pigs that pGz-CPR affords better overall survival, post resuscitation myocardial function, and neurological outcomes compared to conventional chest compression CPR. pGz through pulsatile shear stress on the vascular endothelium elicits acute production of prostaglandins and endothelial-derived nitric oxide (eNO) in whole animal models and in vitro preparations. The salutary effects associated with pGz-CPR compared to chest compression CPR are in part related to endothelial-derived nitric oxide. Both eNO and prostaglandins are cardioprotective in ischemia reperfusion models. To differentiate between the roles of these mediators, indomethacin a non-selective cyclooxygenase inhibitor (COX) was used as a tool to investigate prostaglandin effects during pGz-CPR by acute outcomes of survival, cardioprotection and regional blood flows (RBF). Two groups of anesthetized, intubated pigs weighing 25-36kg were studied. Prior to electrical induction of ventricular fibrillation (VF) animals received equal volumes of either saline placebo Control (CONT) (n=9) or indomethacin (INDO), (n=8), (2mg/kg). After 3min of unsupported VF, both groups received 15min of pGz-CPR followed by pharmacologic and electrical attempts for resuscitation. Return of circulation (ROSC) to 3h occurred in (78%) in CONT and (63%) in INDO pretreated animals. There was no statistically significant difference in hemodynamics between groups at baseline or during the protocol. At baseline, INDO caused a decrease in brain RBF. Two hours after ROSC, INDO blunted the hyperemia response to brain and heart. Echocardiographic evidence of myocardial dysfunction was most notable for the INDO group in the wall motion score index (WMSI). After 3h of ROSC there was a 4-fold difference in both creatine phosphokinase (CPK) and Troponin I concentration between INDO and CONT. Therefore, non-specific acute inhibition of COX in part blunts the salutary effects of pGz-CPR. These data suggest that prostaglandins in part are involved in the cardio protection induced by pGz during CPR. |
7,975 | Genotype-phenotype analysis and natural history of left ventricular hypertrophy in LEOPARD syndrome. | Because it is unclear whether the genotype may influence the clinical course in patients with LEOPARD syndrome (LS), we analyzed clinical and molecular predictors of adverse cardiac events in patients with left ventricular hypertrophy (LVH). A comprehensive cardiovascular evaluation, including baseline electrocardiogram, echocardiography, exercise test and 24 hr Holter monitoring at the time of clinical diagnosis and during follow-up was conducted on 24 patients referred to our departments. Phenotypical examination and diagnosis were performed by expert clinical geneticists. The entire PTPN11 and RAF1 coding regions were screened for mutations by DHPLC analysis, followed by sequencing. Patients without PTPN11 mutations (34%) showed a higher frequency of family history of sudden death (P = 0.007), increased left atrial dimensions (P = 0.05), bradyarrhythmias (P = 0.04), episodes of supraventricular tachycardias (P = 0.06), atrial fibrillation (P = 0.009), and nonsustained ventricular tachycardias (P = 0.05) during Holter monitoring. Six patients (25%) had adverse cardiac events during follow-up (including sudden deaths, resuscitated cardiac arrest, septal myectomy, and heart failure). LVH, New York Heart Association Class, left ventricular outflow tract obstruction, and nonsustained ventricular tachycardias were associated to adverse cardiac events. Of note, three patients with mutations in exon 13 showed a severe obstructive cardiomyopathy, with serious cardiac complications during follow-up (heart failure, septal myectomy, and sudden death). In conclusion, patients with LVH associated with LS seem to carry a relatively high risk of adverse (arrhythmic and nonarrhythmic) events. Further genotype-phenotype studies are warranted to fully elucidate the impact of the genotype on the natural history of patients with LS and LVH. |
7,976 | Antiarrhythmic activity of n-tyrosol during acute myocardial ischemia and reperfusion. | Antiarrhythmic activity of n-tyrosol was demonstrated on the model of early occlusion and reperfusion arrhythmia. The preparation reduces the incidence of ventricular tachycardia and fibrillation, increases the percent of animals without ventricular arrhythmia, and moderates the severity of developing ventricular arrhythmias. |
7,977 | Biphasic versus monophasic shock for external cardioversion of atrial flutter: a prospective, randomized trial. | External cardioversion is effective to terminate persistent atrial flutter. Biphasic shocks have been shown to be superior to monophasic shocks for ventricular defibrillation and atrial fibrillation cardioversion. The purpose of this trial was to compare the efficacy of rectilinear biphasic versus standard damped sine wave monophasic shocks in symptomatic patients with typical atrial flutter.</AbstractText>135 consecutive patients were screened, 95 (70 males, mean age 62 +/- 13 years) were included. Patients were randomly assigned to a monophasic or biphasic cardioversion protocol. Forty-seven patients randomized to the monophasic protocol received sequential shocks of 100, 150, 200, 300 and 360 J. Forty-eight patients with the biphasic protocol received 50, 75, 100, 150 or 200 J.</AbstractText>First-shock efficacy with 50-Joule, biphasic shocks (23/48 patients, 48%) was significantly greater than with the 100-Joule, monophasic waveform (13/47 patients, 28%, p = 0.04). The cumulative second-shock efficacy with the 50- and 75-Joule, biphasic waveform (39/48 patients, 81%) was significantly greater than with the 100- and 150-Joule, monophasic waveform (25/47 patients, 53%, p < 0.05). The cumulative efficacy for the higher energy levels showed naturally no significant difference between the two groups. The amount of the mean delivered energy was significantly lower in the biphasic group (76 +/- 39 J) compared to the monophasic one (177 +/- 78 J, p < 0.05).</AbstractText>For transthoracic cardioversion of typical atrial flutter, biphasic shocks have greater efficacy and the mean delivered current is lower than for monophasic shocks. Therefore, biphasic cardioversion with lower starting energies should be recommended.</AbstractText>(c) 2008 S. Karger AG, Basel.</CopyrightInformation> |
7,978 | The predictive value of transthoracic echocardiographic variables for sinus rhythm maintenance after electrical cardioversion of atrial fibrillation. Results from the CAPRAF study, a prospective, randomized, placebo-controlled study. | The recurrence rate of atrial fibrillation after electrical cardioversion is disappointingly high. The aim of the present study was to prospectively investigate if standard echocardiographic variables at the day of cardioversion could predict sinus rhythm maintenance.</AbstractText>Transthoracic echocardiographic examination was performed within 4 h after cardioversion for all the patients in the CAPRAF (Candesartan in the Prevention of Relapsing Atrial Fibrillation) study.</AbstractText>Cardioversion was successful for 137 patients not given specific antiarrhythmic therapy, and only 41 (30%) maintained sinus rhythm at 6-month follow-up. There were significant (p = 0.05) lower transmitral A wave velocities in the group with relapsing atrial fibrillation compared with the group with sinus rhythm at 6-month follow-up. All patients with the lowest A wave velocities had an early recurrence of atrial fibrillation. There were no differences between the groups regarding atrial dimensions or left ventricular function. The use of the angiotensin II receptor antagonist candesartan had no influence on the echocardiographic variables, nor on the recurrence rate of atrial fibrillation after cardioversion.</AbstractText>Transthoracic echocardiographic examination performed a short time after electrical cardioversion of atrial fibrillation showed that only A wave peak velocities were significantly predictive of sinus rhythm maintenance 6 months after the procedure.</AbstractText>(c) 2008 S. Karger AG, Basel.</CopyrightInformation> |
7,979 | Association of impaired thrombolysis in myocardial infarction myocardial perfusion grade with ventricular tachycardia and ventricular fibrillation following fibrinolytic therapy for ST-segment elevation myocardial infarction. | The goal of this analysis was to evaluate the association of impaired Thrombolysis In Myocardial Infarction myocardial perfusion grade (TMPG) with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF).</AbstractText>Impaired TMPG after successful restoration of epicardial flow among patients treated with fibrinolytic therapy for ST-segment elevation myocardial infarction (STEMI) has been associated with adverse clinical outcomes, but its relationship to VT/VF has not been evaluated.</AbstractText>In the CLARITY-TIMI 28 (Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis In Myocardial Infarction 28) study, 3,491 patients underwent angiography a median of 3.5 days after fibrinolytic administration for STEMI; TMPG was assessed, and its association with VT/VF was evaluated.</AbstractText>We observed VT/VF in 4.8% of patients. Impaired myocardial perfusion (TMPG 0/1/2) was associated with an increased incidence of VT/VF (7.1% vs. 2.6% with TMPG 3; log-rank p < 0.001). Among patients with restoration of normal epicardial flow (Thrombolysis In Myocardial Infarction flow grade 3), the incidence of VT/VF was increased among patients with impaired TMPG (4.7% vs. 2.7%; p = 0.02). Among patients with left ventricular ejection fraction >or=30%, impaired TMPG remained associated with an increased incidence of VT/VF (4.7% vs. 2.5%; p = 0.03). We found that VT/VF was associated with increased mortality (25.2% vs. 3.5%; p < 0.0001). Furthermore, among patients with VT/VF, impaired TMPG was associated with increased mortality (17.1% vs. 2.3%; p = 0.02). All but 1 death among patients who had VT/VF were among patients with impaired myocardial perfusion.</AbstractText>Despite restoration of normal epicardial flow or a left ventricular ejection fraction >or=30%, impaired myocardial perfusion on angiography 3.5 days after fibrinolytic administration for STEMI is associated with an increased incidence of VT/VF.</AbstractText> |
7,980 | Heart transplantation in hypertrophic cardiomyopathy. | Heart transplantation (HT) is the sole therapeutic option for selected patients with hypertrophic cardiomyopathy (HC) and refractory heart failure. However, the results of HT have not been systematically investigated in HC. We assessed the pathophysiologic profile of HT candidates and the outcome after transplantation in 307 patients with HC consecutively evaluated at our tertiary referral center from 1987 to 2005; follow-up was 9.9+8.2 years. Outcome of recipients with HC was compared with that of 141 patients who underwent transplantation for idiopathic dilated cardiomyopathy at our center over the same period. Of 21 patients with HC who entered the transplantation list, 20 had end-stage evolution with systolic dysfunction and 1 had an extremely small left ventricular cavity with impaired filling and recurrent cardiogenic shock during paroxysmal atrial fibrillation. Of 33 study patients with HC who showed end-stage evolution during follow-up, the 23 who were included on the waiting list or died from refractory heart failure (2 patients) were significantly younger than the 10 patients who remained clinically stable (37+/-14 vs 57+/-17 years, p=0.004). Of the 21 HT candidates, 18 underwent transplantation during follow-up. In heart transplant recipients, 7-year survival rate was 94% and not different from that of the 141 patients who received transplants for idiopathic dilated cardiomyopathy (p=0.66). In conclusion, long-term outcome after HT in patients with HC is favorable and similar to that of patients with idiopathic dilated cardiomyopathy. In patients with end-stage HC, young age is associated with more rapid progression to refractory heart failure. |
7,981 | Long term outcome of cavotricuspid isthmus cryoablation for the treatment of common atrial flutter in 180 patients: a single center experience. | Recent literature has shown that common type atrial flutter (AFL) can recur late after cavotricuspid isthmus (CTI) catheter ablation using radiofrequency energy (RF). We report the long term outcome of a large group of patients undergoing CTI ablation using cryothermy for AFL in a single center.</AbstractText>Patients with AFL referred for CTI ablation were recruited prospectively from July 2001 to July 2006. Cryoablation was performed using a deflectable, 10.5 F, 6.5 mm tip catheter. CTI block was reassessed 30 min after the last application during isoproterenol infusion. Recurrences were evaluated by 12-lead ECG and 24 h Holter recording every clinic visit (1/3/6/9 and 12 months after the procedure and yearly thereafter) or if symptoms developed.</AbstractText>The 180 enrolled patients had the following characteristics: 39 women (22%), mean age 58 years, no structural heart disease in 86 patients (48%), mean left atrium diameter 44+/-7 mm and mean left ventricular ejection fraction 57+/-7%. The average number of applications per patient was 7 (3 to 20) with a mean temperature and duration of -88 degrees C and 3 min, respectively. Acute success was achieved in 95% (171) of the patients. There were no complications. After a mean follow-up of 27+/-17 (from 12 to 60) months, the chronic success rate was 91%. The majority of the recurrences occurred within the first year post ablation. One hundred and twenty three patients had a history of atrial fibrillation (AF) prior to CTI ablation and 85 (69%) of those remained having AF after cryoablation. In 20 of 57 (35%) patients without a history of AF prior to CTI ablation, AF occurred during follow-up.</AbstractText>This prospective study showed a 91% chronic success rate (range 12 to 60 months) for cryoablation of the CTI in patients with common type AFL and ratified the frequent association of AF with AFL.</AbstractText> |
7,982 | QT/RR relationship in patients after remote anterior myocardial infarction with left ventricular dysfunction and different types of ventricular arrhythmias. | QT/RR relationship was found to be both rate-dependent and rate-independent, what suggests the influence of autonomic drive and other not-autonomic related factors on it. The steeper QT/RR slope in patients after acute myocardial infarction (MI) was described, but the relationship to ventricular arrhythmias is unknown. The purpose of this study was to calculate differences in QT/RR relationship in patients after remote anterior MI with left ventricular dysfunction and different types of ventricular arrhythmias.</AbstractText>The cohort of 95 patients (age: 63 +/- 11 years, LVEF: 35 +/- 9%) with previous anterior MI (mean 1.1 years) was divided into two well-matched groups-50 patients without episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) (NoVT/VF: 39 males, 64 +/- 12 years, LVEF 37 +/- 8%) and 45 patients with VT and/or VF (all with ICD implanted) (VT/VF: 35 males, 62 +/- 10 years, LVEF 34 +/- 10%). No true antiarrhythmics were used. QT/RR slope was calculated from 24-hour Holter ECG for the entire recording (E), daytime (D) and nighttime (N) periods.</AbstractText>Groups did not differ in basic clinical data (age, LVEF, treatment). QT/RR slopes were steeper in VT/VF than in NoVT/VF group in all analyzed periods: E - 0.195 +/- 0.03 versus 0.15 +/- 0.03 (P < 0.001), N - 0.190 +/- 0.03 versus 0.138 +/- 0.03 (P < 0.001) and D - 0.200 +/- 0.04 versus 0.152 +/- 0.03 (P < 0.001). No significant day-to-night differences were found in both groups.</AbstractText>Steeper QT/RR slope and complete lack of day-to-night differences in VT/VF patients show inappropriate QT adaptation to the heart rate changes. The prognostic significance of this parameter needs prospective studies.</AbstractText> |
7,983 | Cardiac arrhythmias imprint specific signatures on Lorenz plots. | Despite the growing number of studies using Lorenz (Poincaré) plots (LPs) for the analysis of heart rate variability (HRV), a possible correlation between the underlying ECG waveforms and the RR scatter plots has never been systematically studied. We report a comprehensive investigation of distinct Lorenz plot patterns (LPPs) encountered in the context of major cardiac tachyarrhythmias as assessed by 24-hour Holter monitoring and detail the mechanisms underlying the specific LPPs.</AbstractText>The 24-hour ambulatory electrocardiograms (AECGs) of 2700 patients with atrial and/or ventricular tachyarrhythmias and the AECGs of 200 controls with pure sinus rhythm were analyzed using an Elatec arrhythmia analyzing system (Elamedical, Paris 1996). This system allows for the generation of two-dimensional LPs and the exploration of the underlying ECG waveforms. Each LPP obtained was categorized according to its shape and basic geometric parameters. In accordance with the most characteristic LPP feature, the LPPs were grouped into the following distinct classes: 1) comet shape; 2) torpedo shape; 3) H-Fan shape; 4) SZ-Fan shape; 5) double side lobe pattern type A (DSLP-A); 6) double side lobe pattern type B (DSL-B); 7) triple side lobe pattern type A (TSLP-A); 8) triple side lobe pattern type B (TSLP-B);9 island pattern type A (IP-A); 10) island pattern type B (IP-B).</AbstractText>While a comet or a torpedo shape was associated with sinus rhythms, the other LPPs were specifically linked to the presence of cardiac tachyarrhythmias. Thus, a Fan shape was associated with atrial fibrillation or multifocal atrial tachycardia, whereas a DSLP indicated the presence of atrial premature beats, and a TSLP was highly specifically linked to frequent ventricular premature beats. An island pattern was exclusively associated with the presence of an atrial tachycardia or atrial flutter (sensitivity: 100%, specificity: 100%).</AbstractText>Major tachyarrhythmias imprint specific patterns on two-dimensional Lorenz plots generated from 24-hour Holter recordings. Thus, the Lorenz plot method has the potential to significantly improve the accuracy of arrhythmia detection and differentiation, particularly with respect to supraventricular tachyarrhythmias.</AbstractText> |
7,984 | Limited clinical utility of Holter monitoring in patients with palpitations or altered consciousness: analysis of 8973 recordings in 7394 patients. | To determine the clinical utility of 24 hour Holter monitoring by measuring the frequency of candidate arrhythmias recorded during the investigation of palpitations and altered consciousness.</AbstractText>Of 9,729 Holter recordings, reports were available in 8,973 (92.2%) performed in the 7394 patients who comprise the study group. The mean age of the study group was 66 +/- 19 years and 56.4% were women.</AbstractText>The most common indications were altered consciousness (41.7%) and palpitations (36.2%). Among patients with palpitations and sinus rhythm (n=2688), recordings were normal in 2247 (83.6%). Abnormalities included paroxysmal atrial fibrillation (PAF, 6.6%), narrow complex tachycardia (NCT, 2.8%) nonsustained or sustained ventricular tachycardia (NSVT/VT, 2.6%). Among patients with altered consciousness (n=3075), recordings were normal in 2589 (84.2%). Abnormalities included PAF (9.5%), NCT (2.6%), NSV/VT (0.2%), pause >2.8s (2.2%) and high degree AV block (1.3%). The diagnostic yield of Holter monitoring was particularly low in patients aged < or =50 years, of whom 93.1% had palpitations and 95.3% had altered consciousness had normal recordings.</AbstractText>The diagnostic utility of Holter monitoring in patients being investigated for palpitations and altered consciousness is very limited, particularly in young patients for whom alternative diagnostic methods should be considered.</AbstractText> |
7,985 | P-wave duration and dispersion in obese subjects. | Although previous studies have documented a variety of electrocardiogram (ECG) abnormalities in obesity, P-wave alterations, which represent an increased risk for atrial arrhythmia, have not been studied very well in these patients. The aim of the present study was to evaluate P-wave duration and P dispersion (Pd) in obese subjects, and to investigate the relationship between P-wave measurements, and the clinical and echocardiographic variables.</AbstractText>The study population consisted of 52 obese and 30 normal weight control subjects. P-wave duration and P-wave dispersion were calculated on the 12-lead ECG. As echocardiographic variables, left atrial diameter (LAD), left ventricular end-diastolic, and end-systolic diameters (LVDD and LVSD), left ventricular ejection fraction (LVEF), interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), and left ventricular mass (LVM) of the obese and the control subjects were measured by means of transthoracic echocardiography.</AbstractText>There were statistically significant differences between obese and controls as regards to Pmax (maximum P-wave duration) and Pd (P dispersion) (P < 0.001 and P < 0.001, respectively). Pmin (minimum P wave duration) was similar in both groups. Correlation analysis showed that Pd in the obese patients was related to any the clinical and echocardiographic parameters including BMI, LAD, LVDD, IVST, LVPWT, and LVM.</AbstractText>Our data suggest that obesity affects P-wave dispersion and duration, and changes in P dispersion may be closely related to the clinical and the echocardiographic parameters such as BMI, LAD, IVST, LVPWT, and LVM.</AbstractText> |
7,986 | Implantable cardioverter defibrillators save lives from lightning-related electrocution too! | We report an unusual case of a 75-year-old male electrocuted by lightning strike rescued by implantable cardioverter defibrillator (ICD) shock coincidentally. Lightning strikes are an unusual cause of fatal cardiac arrhythmias. Depending on the amount of energy and the current vector affecting the heart, the arrhythmia burden ranges from asystole to ventricular fibrillation. |
7,987 | Mechanisms of ventricular fibrillation initiation in MADIT II patients with implantable cardioverter defibrillators. | The availability of stored intracardiac electrograms from implantable defibrillators (ICDs) has facilitated the study of the mechanisms of ventricular tachyarrhythmia onset. This study aimed to determine the patterns of initiation of ventricular fibrillation (VF) in Multicenter Automatic Defibrillator Implantation Trial (MADIT) II patients along with associated electrocardiogram (ECG) parameters and clinical characteristics.</AbstractText>Examination of stored electrograms enabled us to evaluate the rhythm preceding each episode of VF and to calculate (intracardiac) ECG parameters including QT, QT peak (QTp), coupling interval, and prematurity index.</AbstractText>Sixty episodes of VF among 29 patients (mean age 64.4 +/- 2.5 years) were identified. A single ventricular premature complex (VPC) initiated 46 (77%) episodes whereas a short-long-short (SLS) sequence accounted for 14 (23%) episodes. Of the 29 patients studied, 23 patients had VF episodes preceded by a VPC only, two patients with SLS only, and four patients with both VPC and SLS-initiated episodes. There were no significant differences between initiation patterns in regards to the measured ECG parameters; a faster heart rate with SLS initiation (mean RR prior to VF of 655 +/- 104 ms for SLS and 744 +/- 222 ms for VPC) approached significance (P = 0.06). The two patients with SLS only were not on beta-blockers compared to 83% of the VPC patients.</AbstractText>Ventricular fibrillation is more commonly initiated by a VPC than by a SLS sequence among the MADIT II population. Current pacing modes designed to prevent bradycardia and pause-dependent arrhythmias are unlikely to decrease the incidence of VPC-initiated episodes of VF.</AbstractText> |
7,988 | Removal of CPR artifacts from the ventricular fibrillation ECG by adaptive regression on lagged reference signals. | Removing cardiopulmonary resuscitation (CPR)-related artifacts from human ventricular fibrillation (VF) electrocardiogram (ECG) signals provides the possibility to continuously detect rhythm changes and estimate the probability of defibrillation success. This could reduce "hands-off" analysis times which diminish the cardiac perfusion and deteriorate the chance for successful defibrillations.</AbstractText>Our approach consists in estimating the CPR part of a corrupted signal by adaptive regression on lagged copies of a reference signal which correlate with the CPR artifact signal. The algorithm is based on a state-space model and the corresponding Kalman recursions. It allows for stochastically changing regression coefficients. The residuals of the Kalman estimation can be identified with the CPR-filtered ECG signal. In comparison with ordinary least-squares regression, the proposed algorithm shows, for low signal-to-noise ratio (SNR) corrupted signals, better SNR improvements and yields better estimates of the mean frequency and mean amplitude of the true VF ECG signal.</AbstractText>The preliminary results from a small pool of human VF and animal asystole CPR data are slightly better than the results of comparable previous studies which, however, not only used different algorithms but also different data pools. The algorithm carries the possibility of further optimization.</AbstractText> |
7,989 | Efficacy of automatic mode switching in DDDR mode pacemakers: the most 2 study. | Effective automatic mode switching (AMS) algorithms capable of detecting a range of supraventricular tachyarrhythmias is important given evidence of atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT) post-implantation of pacemakers.</AbstractText>The aim of the study was to assess the efficacy, defined as ability to detect a specific atrial rate and activate AMS, of five different AMS mechanisms during simulation of AF, AFL, and AT.</AbstractText>A total of 48 subjects (35 men, 13 women; mean age: 69 +/- 8 years) implanted with DDDR pacemakers utilizing five different AMS mechanisms (mean atrial rate, rate cut-off, complex 'fallback' algorithm, retriggerable atrial refractory period, and physiological band 'beat-to-beat') were tested using an external electronic device that simulated the occurrence of supraventricular tachyarrhythmias. AF, AFL, and AT were simulated by delivering low voltage pulse trains at 350, 250 and 160 beats/min, respectively.</AbstractText>Mean efficacy for all AMS mechanisms was 81% [range: 57% to 100%] at 350 beats/min, 81% [range: 57-100%] at 250 beats/min, and 79% [range: 57-100%] at 160 beats/min. The AMS mechanisms that yielded 100% efficacy were the rate cut-off and physiological band 'beat-to-beat.'</AbstractText>Not all AMS algorithms are equally efficacious at detecting atrial arrhythmias and subsequently activating AMS. Our results suggest that the most efficacious AMS algorithms are those that use rate cut-off and physiological band 'beat-to-beat' to detect supraventricular tachyarrhythmias.</AbstractText> |
7,990 | The Northern Ireland Public Access Defibrillation (NIPAD) study: effectiveness in urban and rural populations. | To assess the impact of mobile automated external defibrillators (AEDs) on out-of-hospital cardiac arrests (OHCAs) in urban and rural populations.</AbstractText>Prospective before and after intervention, population study.</AbstractText>Urban and rural areas of 160,000 each. Patients, interventions and</AbstractText>In 2004-6 the demographics of OHCAs were assessed. In 2005-6 AEDs were deployed (29 urban, 53 rural): 335 urban first responders (FRs) and 493 rural FRs were trained in AED use and dispatched to OHCAs. Call-to-response interval (CRI), resuscitation and survival-to-discharge rates for OHCA were compared.</AbstractText>In 2004 there were 163 urban OHCAs and the emergency medical services (EMS) attended 158 (ventricular fibrillation (VF) 27/158 (17.1%)). In 2005-6 there were 226 OHCAs, EMS attended 216 (VF 30/216 (13.9%)). In 2005-6 FRs were paged to 128 OHCAs (56.6%), FRs attended 88/128 (68.8%): 18/128 (14.1%) reached before the EMS. The best combined FR/EMS mean (SD) CRI in 2005-6 (5 min 56 s (4)) was better than the EMS alone in 2004 (7 min (3); p = 0.002). Survival rate was 5.1% in 2004, 1.4% in 2005-6 (p = NS). In 2004 there were 131 rural OHCAs, EMS attended 121 (VF 19/121 (15.7%)). In 2005-6 there were 122 OHCAs, EMS attended 114 (VF 19/114 (16.7%)). In 2005-6 FRs were paged to 49 OHCAs, FRs attended 42/49 (85.7%): 23/49 (46.9%) reached before the EMS. The best combined FR/EMS mean (SD) CRI in 2005-6 (9 min 22 s (6)) was better than the EMS alone in 2004 (11 min 2 s (6); p = 0.018). Survival rate was 2.5% in 2004, 3.5% in 2005-6 (p = NS).</AbstractText>Despite improvement in CRI there was no impact on survival (witnessed arrest 32.8%, VF 15.6%).</AbstractText>ISRCTN07286796.</AbstractText> |
7,991 | A case of vagally mediated idiopathic ventricular fibrillation. | A 25-year-old woman experienced three episodes of syncope over the course of 2 years. The attacks all occurred just after she had sat down, and two were accompanied by convulsions. She had no obvious prodromes and no personal or family history of cardiovascular disease.</AbstractText>Electrocardiography, chest radiography, echocardiography, cerebral and cardiac MRI, electroencephalography, 24 h Holter monitoring, electrophysiological study with drug provocation testing and heart-rate variability analysis.</AbstractText>Vagally mediated ventricular fibrillation initiated by premature ventricular complexes arising from the right ventricular outflow tract.</AbstractText>Catheter ablation was performed at the right ventricular outflow tract and an implantable cardioverter-defibrillator was fitted.</AbstractText> |
7,992 | The non-synonymous coding IKr-channel variant KCNH2-K897T is associated with atrial fibrillation: results from a systematic candidate gene-based analysis of KCNH2 (HERG). | Atrial fibrillation (AF) is the most frequent arrhythmia in humans. Rare familial forms exist. Recent evidence indicates a genetic susceptibility to common forms of AF. The alpha-subunit of the myocardial I(Kr)-channel, encoded by the KCNH2 gene, is crucial to ventricular and atrial repolarization. Patients with mutations in KCNH2 present with higher incidence of AF. Common variants in KCNH2 have been shown to modify ventricular repolarization. We intended to investigate, whether such variants may also modulate atrial repolarization and predispose to AF.</AbstractText>In a two-stage association study we analysed 1207 AF-cases and 2475 controls. In stage I 40 tagSNPs (single nucleotide polymorphisms) from the KCNH2 genomic region were genotyped in 671 AF-cases and 694 controls. Of five associated variants, the common K897-allele of the KCNH2-K897T variant was replicated in n = 536 independent AF cases and n = 1781 controls in stage II [overall odds ratio 1.25, 95% confidence interval 1.11-1.41, P = 0.00033]. This association remained significant after adjustment for gender and age.</AbstractText>We report a genetic association finding including positive replication between the K897-allele and higher incidence of AF. This provides a molecular correlate for complex genetic predispositions to AF. The consequences of the K897T variant at the atrial level will require further functional investigations.</AbstractText> |
7,993 | [Acute inferior myocardial infarction masking the J wave syndrome. Based on four observations]. | The J wave syndrome is characterized by a prominent J wave accompanied by ST-segment elevation in the absence of structural heart disease. It includes the benign early repolarization syndrome, the highly arrhythmogenic Brugada syndrome and idiopathic ventricular fibrillation. Although acute coronary syndromes are one of the leading causes of ST-segment deviation, no clinical reports that specifically describe the modulating effects of an ischemic injury current on the ECG manifestations of the J wave syndrome have been found. This report describes four cases of patients with acute inferior ST-segment elevation myocardial infarction who had J wave (or negative deplacement of the J point) and ST-segment depression in the right precordial leads. Later, these precordial ECG alterations disappeared and were progressively replaced by prominent J (R') waves and anterior ST-segment elevations, suggesting the presence of a J wave syndrome. In conclusion, the J wave syndrome may be obscured by an acute inferior myocardial infarction with concomitant ST-segment depression in the right precordial leads. In such circumstances, early detection of the J wave (or depressed J point) may be used as ECG marker of the early repolarization syndrome or Brugada syndrome. |
7,994 | [Out-of-hospital treatment and 1-year survival in patients with ST-elevation acute myocardial infarction. Results of the Spanish Out-of-Hospital Fibrinolysis Evaluation Project (PEFEX)]. | To investigate out-of-hospital treatment, including fibrinolysis, in patients with ST-elevation acute myocardial infarction and to determine the 1-year survival rate.</AbstractText>Prospective cohort study based on an ongoing out-of-hospital registry of patients with ST-elevation acute myocardial infarction who were treated by out-of-hospital emergency teams in Andalusia, Spain during 2001-2004. Patients were followed up in hospital and one year after the acute episode.</AbstractText>The study involved 2372 patients. Out-of-hospital fibrinolysis was used in 467 (19.7%). Among these, 20.7% received treatment within the first hour, 68% within the first 2 hours, and 2 (0.4%) hemorrhagic strokes occurred. Episodes of ventricular fibrillation were recorded in 158 patients (6.7%), 106 (67%) of whom were discharged. In addition, 386 (16.3%) patients died in the short term (both out of and in hospital), with 26 (1.1%) dying before they reached hospital. The cumulative 1-year mortality rate was 22.4% (531 patients) overall, and 6.6% (29 patients) in the out-of-hospital fibrinolysis group. Increased survival at 1 year was associated with out-of-hospital fibrinolysis (odds ratio [OR]=0.368; 95% confidence interval [CI], 0.238-0.566) and percutaneous coronary intervention during admission (OR=0.445; 95% CI, 0.268-0.740).</AbstractText>In routine clinical practice, out-of-hospital fibrinolysis was performed safely, reduced short-term mortality, and improved the 1-year survival rate. The combination of appropriate out-of-hospital treatment, including early defibrillation and fibrinolysis within the first three hours, together with the systematic application of percutaneous coronary intervention during hospital admission is a suitable treatment strategy for the comprehensive care of patients with ST-elevation acute myocardial infarction.</AbstractText> |
7,995 | Surgical methods to reverse left ventricular remodeling. | Heart transplantation remains the gold standard treatment for "end-stage" dilated cardiomyopathy. However, its epidemiologic impact on the heart failure problem continues to be small due to limited donor organ availability and contraindications. Therefore, several "conventional" surgical procedures have been developed to reverse the vicious cycle of ventricular remodeling that accompanies systolic heart failure and to improve symptoms and survival of the patients. This review discusses indications, results, and limitations of the most common surgical methods currently used to arrest or reverse cardiac remodeling. |
7,996 | Inhibiting the renin-angiotensin system with ACE Inhibitors or ARBs after MI. | As part of the recommended modern post-myocardial infarction (MI) management, including reperfusion strategies, antiplatelet therapy, and beta-blockers, we may wonder whether the impact of early inhibition of the renin-angiotensin system (RAS) is as important as it was 20 years ago. This review demonstrates that significant clinical benefit can be derived from angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) even when added to other currently recommended treatment strategies in post-MI patients. Moreover, the effects of RAS inhibition extend far beyond the early post-MI neurohormonal activation and left ventricular remodeling phases. The favorable effects of RAS inhibition on important prognostic markers such as atrial fibrillation, renal function, and diabetes have recently been unraveled. Post-MI RAS inhibition also benefits all age groups, including elderly patients. |
7,997 | Diagnosis and treatment of sleep apnea in heart disease. | One of the most common yet unidentified conditions in heart disease is sleep-disordered breathing (SDB). Although it is most prevalent in patients with heart failure, it has been epidemiologically and pathophysiologically linked to ischemic heart disease, hypertension, sudden cardiac death, atrial fibrillation, and stroke. There are two primary SDB syndromes: obstructive sleep apnea (OSA) and central sleep apnea (CSA; also known as Cheyne-Stokes respiration). The pathophysiologic mechanisms that underlie these disorders appear to be distinct but both involve recurrent cycles of excessive sympathetic activation, hypoxemias and hypercapnias, and increases in ventricular wall stress. Signs and symptoms may include daytime somnolence, snoring, difficult-to-control hypertension, and refractory arrhythmias or angina. In heart failure, half of patients will have SDB and most patients will exhibit evidence of both OSA and CSA, although one or the other may predominate. The current standard diagnostic method is overnight laboratory polysomnography. Primary therapies for OSA include lifestyle changes, various facial and oral appliances, head and neck surgery, and continuous positive airway pressure (CPAP). CPAP is the most effective form of therapy for OSA, with few side effects, but is limited by compliance because of comfort-related issues. In patients with cardiovascular disease who predominantly suffer from OSA, treatment recommendations should be based on current guidelines for OSA. For patients with heart failure with predominant CSA, the current cornerstone of therapy is the optimization of medical therapy and resynchronization therapy when indicated. When SDB persists despite optimal medical management, referral to a sleep medicine consultant should be considered. |
7,998 | Risk stratification and prevention of sudden death in hypertrophic cardiomyopathy. | Sudden cardiac death is the most devastating manifestation of hypertrophic cardiomyopathy (HCM) and often occurs in young and previously asymptomatic patients. Therefore, risk stratification for sudden death has a major role in the management of HCM and has acquired even greater relevance since the implantable cardioverter-defibrillator (ICD) has proved to be highly effective in preventing sudden death in this disease. The ICD is definitely indicated for secondary prevention of sudden death in patients with HCM who have survived a cardiac arrest with documented ventricular fibrillation, or experienced one or more episodes of sustained ventricular tachycardia. However, uncertainties persist regarding the precise selection of patients for primary prophylactic ICD implantation. A number of risk markers are used to assess the magnitude of risk, including family history of premature sudden death; extreme left ventricular (LV) hypertrophy (> 30 mm) in young patients; nonsustained ventricular tachycardia on Holter electrocardiographic recording; unexplained (not neurally mediated) syncope, particularly in young patients; and blood pressure decrease or inadequate increase during upright exercise. Multiple risk factors convey a definite increase in risk. However, a single risk factor such as family history of multiple sudden deaths, massive LV hypertrophy in a young patient, or frequent and/or prolonged runs of nonsustained ventricular tachycardia on Holter, may also justify consideration of a prophylactic ICD. |
7,999 | Ryanodine receptor: a novel therapeutic target in heart disease. | In excitable cells such as skeletal and cardiac myocytes excitation-contraction coupling is an important intermediate step between initiation of the action potential and induction of contraction. This process is predominantly controlled by Ca(2+) release from the sarcoplasmic reticulum via the ryanodine receptor. This very large protein (MW 560 kDa) exists as a homotetramer (~2.2 MDa) and is expressed in three isoforms: RyR1, expressed in skeletal muscle; RyR2, expressed in cardiac muscle; and RyR3, expressed in various cells at lower levels than the other isoforms. Release of Ca(2+) via RyR2 is induced by Ca(2+) influx through L-type Ca(2+) channels and is modulated by multiple factors, including phosphorylation of RyR2 protein by protein kinase A, calmodulin kinase II and FKBP12.6, and stimulation via the beta-adrenergic receptor signaling pathway. Hyperphosphorylation of RyR2 induces Ca(2+) leak during diastole, which can cause fatal arrhythmias and lead to heart failure. This makes RyR2 an important therapeutic target. Although there are few commercially available drugs that inhibit Ca(2+) leak from RyR2, K201 (JTV-519), a benzothiazepine derivative, has emerged as a new ryanodine receptor-selective agent that prevents atrial fibrillation, ventricular arrhythmias, heart failure and exercise-induced sudden cardiac death. In this review, we discuss recent advances in our understanding of the basic structure and function of ryanodine receptors, their involvement in heart disease, and the development of drugs to prevent ryanodine receptor malfunction and recent patents. |
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