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7,300 | Long-term safety and efficacy of right ventricular outflow tract pacing in patients with permanent pacemakers. | The aim of the present study was to investigate long-term safety and change in pacing parameters of right ventricular outflow tract (RVOT) pacing.</AbstractText>This prospectively designed controlled clinical study comprised patients in Group 1 (n=16) and Group 2 (n=16) who were paced in RVOT and right ventricular apex (RVA), respectively, and were selected from patients with permanent pacemakers who were routinely followed up at our pacemaker clinic. Commercially available active fixation leads were used in all patients. Pacing parameters were compared at implant and long-term follow-up visits. Statistical analyses were performed using Pearson Chi-Square, nonparametric Mann-Whitney U and Wilcoxon Signed Ranks tests.</AbstractText>The mean duration of follow-up was 38.3+/-18.0 months for RVOT and 30.4+/-20.0 months for RVA (p=0.255). Impedance values, pacing thresholds and R wave amplitudes measured at implant and last pacemaker check did not significantly differ between RVOT and RVA pacing groups. There was no lead dislodgment or any other procedure related complication during follow-up.</AbstractText>Right ventricular outflow tract pacing site is safe and pacing impedance and threshold values are comparable with conventional RVA pacing in the long-term.</AbstractText> |
7,301 | Azimilide reduces emergency department visits and hospitalizations in patients with an implantable cardioverter-defibrillator in a placebo-controlled clinical trial. | The goal of this study was to determine whether azimilide, as compared with placebo, will reduce the number of emergency department (ED) visits and hospitalizations caused by arrhythmias or cardiac events in patients with an implantable cardioverter-defibrillator (ICD).</AbstractText>Patients with an ICD may require ED visits and hospitalizations because of arrhythmias, which trigger ICD therapies. The effect of adjunctive antiarrhythmic therapy on these outcomes is not known.</AbstractText>A total of 633 patients with an ICD were randomized in the SHIELD (SHock Inhibition Evaluation with AzimiLiDe) trial, a blinded, placebo-controlled randomized trial of the investigational class III antiarrhythmic azimilide (75 and 125 mg/day), and, prospectively, cardiac and arrhythmic ED visits and hospitalization data were collected over 1 year.</AbstractText>All patients had symptomatic sustained ventricular tachycardia (72%) or ventricular fibrillation (28%) before study entry. Overall, 44% (n = 276) experienced at least 1 cardiac ED visit or hospitalization. Among 214 patients assigned to placebo, 38.3% had at least 1 arrhythmic-related ED visit or hospitalization compared with 21.8% of 220 patients assigned to 75-mg azimilide (p < 0.001) and 27.6% of 199 patients assigned to 125 mg azimilide (p < 0.05). Symptomatic ventricular tachycardia treated by antitachycardia pacing, shocks, and shocks plus symptomatic arrhythmias were significant predictors of cardiac-related ED visits or hospitalizations (relative risk: 2.0, 3.0, and 3.1, respectively). In a stepwise logistic regression model, the presence of congestive heart failure (New York Heart Association functional class II/III) was the only additional independent predictor of cardiac ED visits or hospitalizations.</AbstractText>Azimilide significantly reduces the number of ED visits and hospitalizations in patients with an ICD at high risk of arrhythmias.</AbstractText> |
7,302 | Amiodarone induced pneumonitis and hyperthyroidism: case report. | Amiodarone is a highly effective antiarrhythmic agent used in life-threatening ventricular and supraventricular arrhythmias. Its long-term use may however lead to several adverse effects, including corneal deposits, liver and thyroid gland dysfunction, lung lesions, bone marrow injury, skin lesions, or neurological abnormalities. The article presents the case of a 56-year-old man with a history of a stroke, who after a few days of amiodarone therapy for an episode of atrial fibrillation was diagnosed with amiodarone-induced hyperthyroidism and interstitial pulmonary lesions. Clinical and laboratory symptoms of hyperthyroidism and radiographic signs of pulmonary involvement did not occur until several weeks after discontinuation of amiodarone therapy. Differential diagnosis of causes of hyperthyroidism and diseases causing nodular pulmonary lesions did not demonstrate any other pathologies. Empirical antibiotic therapy and administration of thiamazole and high doses of propranolol failed to improve the patient's clinical status. It was not until thiamazole was given in combination with glucocorticosteroids, when a slow relief of hyperthyroidism symptoms and resolution of radiographic pulmonary signs were observed. Based on the presented case, the risk of appearance of 2 serious concomitant adverse effects was demonstrated, even following a short-term amiodarone therapy. This paper also contains an overview of adverse effects which may be encountered during or after therapy with this effective antiarrhythmic agent. It was emphasized how important it is to select patients appropriately, and to monitor potential adverse effects during amiodarone therapy. |
7,303 | Mitral valve repair: beyond the French correction. | We analysed retrospectively patients who underwent mitral valve repair using techniques beyond the "French correction", as popularised by Carpentier.</AbstractText>From June 1997 to June 2006, 153 patients underwent mitral valve repair. Their mean age was 63.1 +/- 13.5 years (range 19-87). Mean Euroscore was 4.9 +/- 2.1 (2-13). Type II lesions were present in 109 cases. There were 123 degenerative cases. Preoperative mitral regurgitation (MR) was severe in 145 cases. Ninety patients were in NYHA class III/IV. The transseptal approach was employed in 89.5% of the series. Annuloplasty alone was performed in 36 patients, whereas leaflet plication/exclusion was applied in 53 patients. The edge-to-edge technique was used in 79. Mitral valve repair was combined with procedures for ischaemic heart disease in 41 patients.</AbstractText>The mean postoperative stay was 8.1 +/- 3.7 days (4-25). There was no mortality in the isolated mitral valve repair group. New onset atrial fibrillation occurred in 17% postoperatively. Mean follow-up was 34.3 +/- 25.1 months (0-105). No or mild MR was present in 139 (91%) patients, while 144 (94%) were in NYHA class I. Four patients underwent redo repair. There was a statistically significant difference in relation to the MR between patients who had Alfieri repair with annuloplasty compared to no annuloplasty (p < 0.001). Furthermore, there was a significant difference between the isolated valve and the combined group in terms of postoperative hospital stay (p = 0.006) and survival (p = 0.033).</AbstractText>Our study demonstrates that the techniques beyond the "French correction" simplify the repair, especially when combined with other cardiac procedures. These techniques were applied with no mortality in the isolated mitral valve repair group.</AbstractText> |
7,304 | Ventricular arrhythmias and antioxidative medication: experimental study. | Reperfusion arrhythmias could be due to free radicals, while contraction excitation feedback is the cause of arrhythmias generated by blood pressure elevation (BPE). The aim of this study was to test the antiarrhythmic effects of an antioxidant (vitamin C [vit C], 1.5 g), an iron-binding agent (deferoxamine [Def], 1 g), and their combination in an experimental model of arrhythmia based on these 2 mechanisms.</AbstractText>Thirty anaesthetised sheep were divided into 4 groups, depending on the infused agent: saline (8 sheep), combination of vit C and Def (8), Def (6), and vit C (8). Induction of ventricular arrhythmias was attempted in all animals using both ischaemia-reperfusion (phase I) and a combination of ischaemia and BPE (phase II). In all cases ischaemia was caused by ligating the left anterior descending coronary artery distally to the origin of the 1st diagonal artery, while reperfusion was achieved by releasing the ligation 45 min later. BPE was achieved by obstructing the ascending aorta or by administering intravenous metaraminol. All agents were infused intravenously for 15 min and their administration was started 30 min after the first ligation. Phases I and II lasted 50 and 20 min, respectively.</AbstractText>Ventricular tachycardia/fibrillation (VT/VF) was induced in all animals in the control group (8/8) and in the Def group (6/6). VT/VF appeared in 6/8 of the animals in the vit C group (75%) and in only 3/8 of the animals in the combination therapy group (37.5%). The difference between the combination and control groups was statistically significant (p < 0.03).</AbstractText>The intravenous administration of vit C and Def in combination protects against VT/VF induced by ischaemia-reperfusion and/or BPE. Administration of Def alone does not appear to help, while the action of vit C alone is not clear.</AbstractText> |
7,305 | [Occurrence of arrhythmias related to treatment of myocardial infarction]. | Percutaneous coronary catheter intervention (PCI) reduces mortality in ST-elevation myocardial infarction (STEMI) more than fibrinolysis. However, it remains uncertain whether PCI reduces the incidence of early post-infarction arrhythmias.</AbstractText>We compared the incidence of arrhythmias in two groups of consecutive STEMI-patients who underwent continuous ECG monitoring. One group was treated with PCI in 2006-07, while a historic control group received thrombolysis in 1996-98.</AbstractText>93 (38%) PCI patients and 97 (53%) of the thrombolysed patients (p = 0.001) had arrhythmias. 27% of the patients in the PCI group were treated for arrhythmias vs. 34% of the thrombolysed (n.s.). Significantly fewer PCI-treated patients had atrial fibrillation (5% vs. 16%), AV-block II/III (0% vs. 6%) and asystole (0% vs. 5%), but an increased frequency of ventricular tachycardia was recorded (10% vs. 5%). 41% of all arrhythmic and 63% of treated events occurred in the first hour after PCI; corresponding results for thrombolysis were 23% and 28% (p = 0.000). Mortality was greater in the thrombolysed group (11% vs. 2%, p = 0.006), but patients were older, had more risk factors and larger emit ions of cardiac enzymes. After adjustment for the confounding effects of age, gender, score for ST-elevation and infarct localization, there was still a reduction in total arrhythmias in the PCI-treated group (odds ratio 0.37, 95% confidence interval 0.19-0.73, p = 0.004).</AbstractText>PCI-treatment seems to reduce early post-STEMI arrhythmias, but a non-randomized design and the use of historical controls, reduce the strength of this conclusion.</AbstractText> |
7,306 | Peroxynitrite decreases arrhythmias induced by ischaemia reperfusion in anaesthetized dogs, without involving mitochondrial KATP channels. | Exogenous peroxynitrite from nanomolar to micromolar concentrations exerts cardioprotection. Here, we have assessed its effects on ischaemia- and reperfusion-induced ventricular arrhythmias in vivo and a possible role for mitochondrial K(ATP) channels in these effects, using the channel inhibitor 5-hydroxydecanoate (5-HD).</AbstractText>Chloralose-urethane-anaesthetized dogs were treated twice for 5 min with peroxynitrite (100 nM, by intracoronary infusions) in both the absence and presence of 5-HD (150 microg kg(-1) min(-1)), and then subjected to 25 min occlusion of the left anterior descending coronary artery. The severity of ischaemia and of arrhythmias, as well as the levels of nitrotyrosine were assessed and compared with a group of control dogs, subjected only to a 25 min occlusion and reperfusion insult.</AbstractText>Compared with controls, infusion of peroxynitrite markedly suppressed the number of ventricular premature beats (388+/-88 vs 133+/-44), the incidence of ventricular fibrillation both during occlusion (50% vs 10%) and reperfusion (100% vs 44%), and increased survival (0% vs 50%; all P<0.05). The severity of ischaemia (epicardial ST-segment changes, inhomogeneity of electrical activation) during occlusion and nitrotyrosine levels on reperfusion were significantly less in the peroxynitrite-treated dogs than in the controls. 5-HD did not modify the cardioprotective effects of peroxynitrite.</AbstractText>Exogenous peroxynitrite provided antiarrhythmic protection in vivo, which might have been on account of a reduction in endogenous peroxynitrite formation. This protection seemed not to be mediated through mitoK(ATP) channels.</AbstractText> |
7,307 | Endothelin-1 is not predictive of ventricular ectopy or ventricular fibrillation during acute myocardial ischemia. | Endothelin(ET)-1 (ET-1) increases after myocardial infarction and may have effects on myocardial function. ET-1 has also been shown to affect the action potential (AP) which may be arrhythmogenic and predispose to ventricular fibrillation (VF). The effects of ET-2 and ET-3 are uncertain. We hypothesized that the ETs increase during acute ischemia and that plasma levels are predictive of ischemically induced VF. Thirty-four domestic swine underwent balloon occlusion of the proximal LAD coronary artery. Occlusion was confirmed angiographically. Venous samples were collected from the right atrium at baseline and at 5 min intervals for 30 min or until VF induction. ET-1, ET-2, and ET-3 were measured using ELISA. Changes in plasma concentrations were assessed using repeated measures ANOVA with Dunnett's. A p < 0.05 was considered statistically significant. All animals had angiographic evidence of successful proximal LAD occlusion. ET-1 levels were significantly increased from a baseline at 20 min and remained elevated during 30 min of occlusion. ET-2 and ET-3 levels did not change from baseline values (figure, mean +/- SE). VF occurred in 60% of animals. Peak ET-1 values were not significantly different between VF and non-VF animals (6.2 +/- 2.2 vs. 4.8 +/- 2.3 pg/mL). No single ET-1 value had a VF predictive value >50%. There is a significant increase in ET-1 level within 20 min of acute myocardial ischemia. Despite known effects of ET-1 on the AP, this increase did not correlate with the occurrence of VF. |
7,308 | ECG scaling properties of cardiac arrhythmias using detrended fluctuation analysis. | We applied detrended fluctuation analysis to characterize at very short time scales during episodes of cardiac arrhythmias the raw electrocardiogram (ECG) waveform, aiming to get a global insight into its dynamical behaviour in patients who experienced sudden death. We found that in 15 recordings involving different types of arrhythmias (taken from PhysioNet's Sudden Cardiac Death Holter Database), the ECG waveform, besides showing a less-random dynamics, becomes more regular during bigeminy, ventricular tachycardia or even atrial fibrillation and ventricular fibrillation. The ECG waveform scaling properties thus suggest that reduced complexity dominates the underlying mechanisms of arrhythmias. Among other explanations, this may result from shorted or restricted (i.e. less diverse) pathways of conduction of the electrical activity within ventricles. |
7,309 | Epicardial ultrasonic ablation of atrial fibrillation during concomitant cardiac surgery is a valid option in patients with ischemic heart disease. | Surgical therapy of atrial fibrillation concomitant to coronary bypass grafting using epicardial Ultrasound technology was assessed after a minimum 6-month follow-up.</AbstractText>A cohort of 98 consecutive patients with a mean age of 72+/-7.58 years and a primary diagnosis of ischemic heart disease had surgery for structural disease. Coronary artery bypass grafting was isolated (n=51) or associated (n=47) with various combinations of aortic, mitral, tricuspid, and left ventricular restoration surgery. Atrial fibrillation duration ranged from 6 to 360 months (mean 71 months) and was permanent in 47 patients, paroxysmal in 34, and persistent in 17. Left atrial mean diameter was 48+/-6.71 mm. A circumferential ablation was performed off-pump, before the concomitant procedure, and was always associated with an epicardial mitral line lesion using the same technology. At 3-, 6-, and 12-month visits, patients were routinely evaluated by physical examination, ECG, chest X-ray, and 24-hour Holter. There were 1 early death (1%) and 4 extracardiac late deaths. A pacemaker was implanted in 4 patients. Mean follow-up time was 325 days, 2 patients being lost to follow-up. Freedom from atrial fibrillation and flutter at the 6-month visit was 84% for the entire population, 76% in patients with permanent, and 91% in patients with paroxysmal atrial fibrillation. At the 1-year visit, 85% were free from atrial fibrillation or flutter.</AbstractText>Epicardial beating heart ablation using therapeutic ultrasound is safe, reliable, and can easily treat atrial fibrillation in a difficult surgical population of patients with primary ischemic heart disease.</AbstractText> |
7,310 | [Automatic external defibrillator--mode of operation and clinical use]. | Every year about 100,000 persons die from sudden cardiac death (SCD) in Germany. Although many efforts have been undertaken, mortality remains high. Only 2 - 10% of patients with out-off hospital SCD can finally be discharged from hospital after resuscitation. Observational studies show that ventricular fibrillation and ventricular tachycardia are the primary arrhythmias underlying SCD. For both arrhythmias the main determinant for survival is the time between onset and termination by defibrillation. The chance of survival declines by 10% for every minute of delay. These findings prompted the concept of early defibrillation by first responders. Many studies have shown that non-medical professionals, like police men, firemen or security officers, often arrive at the patient more early than emergency medical service. Thus, "smart" automated external defibrillators (AEDs), designed to identify VT/VF and prompt the user when to deliver a shock were introduced. These devices allow lay rescuers to terminate ventricular arrhythmias before the arrival of medical professionals. By this approach the time to defibrillation could be reduced and a significant reduction in mortality could be documented in selected situation. These encouraging results initialled the installation of AED at public places like aircrafts, airports, underground stations and shopping males. Due to the success of this approach doctors are more and more confronted with questions about technical details, reliability and cost effectiveness of these devices. The present review should give an overview about the current studies and guidelines. |
7,311 | Chemical sympathetic denervation, suppression of myocardial transient outward potassium current, and ventricular fibrillation in the rat. | Sympathetic denervation is frequently observed in heart disease. To investigate the linkage of sympathetic denervation and cardiac arrhythmia, we developed a rat model of chemical sympathectomy by subcutaneous injections of 6-hydroxydopamine (6-OHDA). Cardiac sympathetic innervation was visualized by means of a glyoxylic catecholaminergic histofluorescence method. Transient outward current (Ito) of ventricular myocytes was recorded with the whole-cell configuration of the patch clamp technique. We observed that sympathectomy (i) decreased cardiac sympathetic nerve density and norepinephrine level, (ii) reduced the protein expression of Kv4.2, Kv1.4, and Kv channel-interacting protein 2 (KChIP2), (iii) decreased current densities and delayed activation of Ito channels, (iv) reduced the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and cAMP response element-binding protein (CREB), and (v) increased the severity of ventricular fibrillation induced by rapid pacing. Three weeks after 6-OHDA injections, which allowed time for sympathetic regeneration, we found cardiac sympathetic nerve density, norepinephrine levels, expression levels of Kv4.2 and KChIP2 proteins, and I(to) densities were partially normalized and ventricular fibrillation severity was decreased. We conclude that chemical sympathectomy downregulates the expression of selective Kv channel subunits and decreases myocardial I(to) channel activities, contributing to the elevated susceptibility to ventricular fibrillation. |
7,312 | Granulocyte colony-stimulating factor reduces mortality by suppressing ventricular arrhythmias in acute phase of myocardial infarction in rats. | Our aim was to evaluate the effects of granulocyte colony-stimulating factor (G-CSF) on early cardiac arrhythmias after myocardial infarction (MI) and the impact on survival. Male Wistar rats received repeated doses of 50 mug/kg G-CSF (MI-GCSF group) or vehicle (MI group) at 7, 3, and 1 days before surgery. MI was induced by permanent occlusion of left coronary artery. The electrocardiogram was obtained before occlusion and then for 30 minutes after surgery. Events and duration of ventricular arrhythmias were analyzed. The levels of connexin43 (Cx43) were measured by Western blot immediately before MI production. Survival was significantly increased in MI-GCSF pretreated group (74% versus 52.9% MI, P < 0.05). G-CSF pretreatment also significantly reduced the ventricular premature beats when compared with the untreated-MI group (201 +/- 47 versus 679 +/- 117, P < 0.05). The number and the duration of ventricular tachycardia were smaller in the MI-G-CSF group, as well as the number of ventricular fibrillation episodes (10% versus 69% in MI, P < 0.05). Cx43 levels were significantly increased by G-CSF treatment (1.27 +/- 0.13 versus 0.86 +/- 0.11; P < 0.05). The MI size 24 hours after occlusion was reduced by G-CSF pretreatment (36 +/- 3% versus 44 +/- 2% of left ventricle in MI group; P < 0.05). The increase of Cx43 expression in the heart may explain the reduced incidence in ventricular arrhythmias in the early phases after coronary artery occlusion in rats, thus increasing survival after MI. |
7,313 | [Interventional cardiology]. | Interventional cardiology has dramatically developed since its introduction in 1977. Angioplasty represents the first choice for coronary reperfusion during acute myocardial infarction with thromboaspiration and stenting of the culprit lesion. In acute coronary syndroms and stable angina or silent ischemia despite optimal medical treatment, angioplasty is today an excellent option for coronary revascularization which includes a technologic offer adapted to various clinical and anatomical situations (specific guidewires, rotative atherectomy, distal protection devices and drug eluting stents that reduce the risk of coronary reintervention after initial angioplasty). For patient with severe ischemic left ventricular dysfunction, interventional rythmology can improve patient prognosis by a limitation of lethal ventricular fibrillation. Despite the hope that intracoronary cell transplantation could save myocardial cells, several randomized control trials have given various and disappointing results concerning the potential improvement of left ventricular function. Interventional cardiology nowadays offers global technical solutions for more and more patients suffering from ischemic cardiomyopathy. |
7,314 | Epicardial mapping of ventricular fibrillation over the posterior descending artery and left posterior papillary muscle of the swine heart. | Recent studies suggest that during ventricular fibrillation (VF) epicardial vessels may be a site of conduction block and the posterior papillary muscle (PPM) in the left ventricle (LV) may be the location of a "mother rotor." The goal of this study was to obtain evidence to support or refute these possibilities.</AbstractText>Epicardial activation over the posterior LV and right ventricle (RV) was mapped during the first 20 s of electrically induced VF in six open-chest pigs with a 504 electrode plaque covering a 20 cm(2) area centered over the posterior descending artery (PDA).</AbstractText>The locations of epicardial breakthrough as well as reentry clustered in time and space during VF. Spatially, reentry occurred significantly more frequently over the LV than the RV in all 48 episodes, and breakthrough clustered near the PPM (p < 0.001). Significant temporal clustering occurred in 79% of breakthrough episodes and 100% of reentry episodes. These temporal clusters occurred at different times so that there was significantly less breakthrough when reentry was present (p < 0.0001). Conduction block occurred significantly more frequently near the PDA than elsewhere.</AbstractText>The PDA is a site of epicardial block which may contribute to VF maintenance. Epicardial breakthrough clusters near the PPM. Reentry also clusters in space but at a separate site. The fact that breakthrough and reentry cluster at different locations and at different times supports the possibility of a drifting filament at the PPM so that at times reentry is present on the surface but at other times the reentrant wavefront breaks through to the epicardium.</AbstractText> |
7,315 | Electrophysiologic and histopathologic findings of the ablation sites for ventricular fibrillation in a patient with ischemic cardiomyopathy. | We examined autopsy specimens from a patient with ischemic cardiomyopathy who underwent radiofrequency catheter ablation of ventricular fibrillation. There was site specific arrhythmogenesis of the trigger ventricular premature contractions (VPCs) and Purkinje potentials were recorded before the onset of the QRS. In postmortem examination, fibromuscular bands connecting the posterior papillary muscle and ventricular septum were recognized at the successful ablation sites of the trigger VPCs and the microscopic examinations revealed Purkinje cells in the center of that fibromuscular band. |
7,316 | Early repolarization and sudden cardiac arrest: theme or variation on a theme? | The association between early repolarization patterns on electrocardiograms and risk of idiopathic ventricular fibrillation reported by Haïssaguerre et al. raises questions about the generally held concept that early repolarization is a benign electrocardiographic pattern. Although the association reported is strong enough to suggest validity, the data do not permit distinction between the following two possibilities: that early repolarization is a single pathophysiological entity with variable expression, or that early repolarization is a nonspecific electrocardiographic pattern that might be associated with specific high-risk or low-risk entities. Until prospective population data are available, physicians should continue to view this common electrocardiographic variant as generally benign. Careful attention should, however, be paid to patients with early repolarization and J-point elevations of more than 2 mm, especially those with otherwise unexplained arrhythmias or a family history of unexplained sudden death. |
7,317 | Fragmented QRS as a marker of conduction abnormality and a predictor of prognosis of Brugada syndrome. | Conduction abnormalities serve as a substrate for ventricular fibrillation (VF) in patients with Brugada syndrome (BS). Signal-averaged electrograms can detect late potentials, but the significance of conduction abnormalities within the QRS complex is still unknown. The latter can present as multiple spikes within the QRS complex (fragmented QRS [f-QRS]). We hypothesized that f-QRS could indicate a substrate for VF and might predict a high risk of VF for patients with BS.</AbstractText>In study 1, we analyzed the incidence of f-QRS in 115 patients with BS (13 resuscitated from VF, 28 with syncope, and 74 asymptomatic). f-QRS was observed in 43% of patients, more often in the VF group (incidence of f-QRS: VF 85%, syncope 50%, and asymptomatic 34%, P<0.01). SCN5A mutations occurred more often in patients with f-QRS (33%) than in patients without f-QRS (5%). In patients with syncope or VF, only 6% without f-QRS experienced VF during follow-up (43+/-25 months), but 58% of patients with f-QRS had recurrent syncope due to VF (P<0.01). In study 2, to investigate the mechanism of f-QRS, we studied in vitro models of BS in canine right ventricular tissues (n=4) and optically mapped multisite action potentials. In the experimental model of BS, ST elevation resulted from a large phase 1 notch of the action potential in the epicardium, and local epicardial activation delay reproduced f-QRS in the transmural ECG.</AbstractText>f-QRS appears to be a marker for the substrate for spontaneous VF in BS and predicts patients at high risk of syncope.</AbstractText> |
7,318 | Drug induced shortening of the QT/QTc interval: an emerging safety issue warranting further modelling and evaluation in drug research and development? | A session dedicated to the issue of drug-induced QT and/or QTc interval (QT/QTc) shortening of the electrocardiogram (ECG) was held at the 2007 Safety Pharmacology Society (SPS) meeting in Edinburgh.</AbstractText>The session included a presentation on the results of a cross company survey on QT/QTc-shortening, a podium debate with speakers arguing "for" and "against" QT/QTc shortening being a safety issue and a panel discussion with the audience.</AbstractText>Compared to QT/QTc prolongation, relatively little is known about the relevance to safety of drug-induced QT/QTc shortening. As with QT/QTc prolongation, there are genetic syndromes and pharmaceutical agents which cause shortening of QT/QTc. The potential safety issue of QT/QTc shortening and its suitability as a biomarker of drug-induced cardiac arrhythmias, are unclear, however, the type of arrhythmia associated with prolongation and shortening are thought to differ. Prolongation is associated with torsades de pointes, whereas, shortening of QT/QTc is proposed to be associated with the more severe arrhythmia, ventricular fibrillation (VF). The industry-wide survey (53 total responses representing 45 different companies) indicates that the number of compounds that induce QT/QTc shortening has increased over the past 5 years with 51% of responses reporting QT/QTc shortening in pre-clinical studies and 22% reporting a corresponding clinical experience. The reason for the increase is not clear but there is a clear business impact with 13% (7/56) of these compounds being discontinued in the pre-clinical phase due to QT/QTc shortening. The majority of companies with clinical experience of QT/QTc shortening have engaged with the regulatory agencies and these experiences will be valuable in shaping how the pharmaceutical industry and the agencies view drug-induced QT/QTc shortening in the future.</AbstractText>Currently it is not clear how much shortening of QT/QTc is required before it might be considered a safety issue and indeed, whether QT/QTc shortening is a suitable biomarker for cardiac arrhythmias. It is clear, however, that with our current understanding, compounds which shorten QT/QTc will attract close regulatory scrutiny and carry a business risk. The need to better understand this potential cardiac safety issue points to further research including; model development to determine the mechanism(s) of action of drug-induced QT/QTc shortening and the translation between the non-clinical and clinical situation.</AbstractText> |
7,319 | Nifekalant and disopyramide in a patient with short QT syndrome: evaluation of pharmacological effects and electrophysiological properties. | We assessed several pharmacological effects on electrocardiogram parameters and effective refractory period (ERP) in a patient with a short QT syndrome (SQTS). Pharmacological challenge tests revealed that disopyramide and selective I(kr) blocker, nifekalant normalized QT interval, and ERP of the atrial and ventricular myocardium. This study suggested that disopyramide and nifekalant should be feasible for the drug treatment of the SQTS. Moreover, QT interval was paradoxically prolonged at higher heart rates induced with isoproterenol infusion or an exercise test, although the mechanism of this QT prolongation remains to be investigated. |
7,320 | Atrial and ventricular arryhthmogenic potential in Turner Syndrome. | P-wave dispersion (Pd), corrected P-wave dispersion (Pdc), QT-wave dispersion (QTd), and corrected QT-wave dispersion (QTdc) parameters were not assessed in Turner Syndrome (TS) before. The aim of this study is to investigate the cardiac arrhythmogenic potential in patients with TS.</AbstractText>Thirty-one patients with TS and 30 healthy women were enrolled in the study. For this purpose 12-lead electrocardiogram (ECG) and 24-hour ambulatory ECG recordings were performed.</AbstractText>Pd, Pdc, QTd, and QTdc were significantly higher in patients with TS. On 24-hour ambulatory ECG recording, the mean heart rate (HR) was higher, while the mean of all RR intervals between normal beats (MeanNN), the standard deviation of all the RR intervals (SDNN), the square root of the mean of the squared differences of two consecutive RR intervals (rMSSD), and the percentage of the beats with consecutive RR interval difference more than 50 milliseconds (pNN50) were lower in TS.</AbstractText>There were significant increases in Pd, Pdc, QTd, and QTdc in patients with TS and they may be features of the disease. The frequency of supraventricular arrhythmias was increased. There also was a significant deterioration of sympathetic and parasympathetic components of autonomic function as assessed by heart rate variability (HRV) in Turner patients.</AbstractText> |
7,321 | Atrial fibrillation is associated with decreased cardiac sympathetic response to isometric exercise in CHF in comparison to sinus rhythm. | The presence of atrial fibrillation (AF) in congestive heart failure (CHF) is accompanied by increased mortality, although the exact mechanism is unclear. In previous studies, we have demonstrated cardiac baroreceptor abnormalities in association with AF and CHF. In this study, we sought to examine the effect of cardiac rhythm on the cardiac sympathetic response to exercise in CHF.</AbstractText>In 13 CHF patients (six AF, seven SR, left ventricular ejection fraction 31 +/- 2%, age 61 +/- 1 years), we measured the hemodynamic and cardiac sympathetic response isometric handgrip (IHG) exercise.</AbstractText>At baseline the groups were well matched. Baseline hemodynamics and cardiac sympathetic activity did not significantly differ between the cohorts. In response to IHG exercise, both groups demonstrated significant hemodynamic responses. In conjunction, the sinus rhythm (SR) group demonstrated a significant increase in cardiac sympathetic response to exercise (P = 0.04) while in contrast the AF group did not (P = 0.6).</AbstractText>In this study, we demonstrate for the first time that the combination of AF and CHF is accompanied by a marked attenuation of the cardiac sympathetic response to acute hemodynamic stress. This implies AF is associated with a further impairment of baroreceptor response in CHF compared to SR. These findings present possible insights to the associated increased mortality and pathogenesis of AF with CHF.</AbstractText> |
7,322 | Steroid induced atrial fibrillation. | A 72-year-old female presented with an acute flaure of Crohn's disease and received intravenous methylprednisolone. The following morning ECG showed atrial fibrillation with a rapid ventricular response of 111 bts/min, which spontaneously resolved within 7 hours. The underlying arrhythmogenenic mechanism is unknown. |
7,323 | Vasopressin for the management of catecholamine-resistant anaphylactic shock. | Severe anaesthetic anaphylaxis is relatively uncommon. Oxygen, fluids and epinephrine are considered to be the mainstay for treatment of cardiovascular collapse and current guidelines for the management of anaphylaxis list only epinephrine as a vasopressor to use in the event of a cardiovascular collapse. Recently, evidence has emerged in the support of the use of vasopressin in cardiopulmonary resuscitation; it is also recommended for the treatment of ventricular fibrillation, septic shock and post-cardiopulmonary bypass distribution shock. Currently, there is no algorithm or guideline for the management of anaphylaxis that include the use of vasopressin. We report a 24-year-old woman who developed severe anaphylactic shock at induction of anaesthesia while undergoing laparoscopic cholecystectomy. Circulation shock was refractory to epinephrine and high doses of pure alpha-agonist phenylephrine and norepinephrine. Single intravenous dose of two units of vasopressin re-established normal circulation and blood pressure. |
7,324 | Sildenafil citrate on the inducibility of ventricular fibrillation and upper limit of vulnerability in swine. | Sildenafil citrate at supratherapeutic levels has been reported to decrease defibrillation efficacy. However, its effects on ventricular fibrillation induction and the upper limit of vulnerability (ULV) have not been investigated. We tested the hypothesis that sildenafil citrate reduces the ventricular fibrillation threshold (VFT) and increases the ULV.</AbstractText><AbstractText Label="MATERIAL/METHODS" NlmCategory="METHODS">Twenty-one pigs (25-30 kg) were randomly assigned into 3 groups of 7 pigs each. A solution containing 100 mg (group 100) or 50 mg (group 50) sildenafil citrate or 100 cc saline (group control) was infused intravenously in each pig. A train of 10 S1s was delivered from an RV electrode, and an S2 stimulus was delivered at the peak of the T wave of the last S1 activation to determine the VFT and ULV, before and after drug administration.</AbstractText>The 100 mg sildenafil citrate significantly (P<0.03) decreased VFT, accounting for approximately 36% by peak voltage and approximately 52% by total energy, and significantly (P<0.009) increased ULV, accounting for approximately 28% by peak voltage, and approximately 56% by total energy.</AbstractText>Supratherapeutic concentrations of sildenafil citrate significantly decreased the VFT and increased the ULV, resulting in an expansion of the VF induction window during the vulnerable period.</AbstractText> |
7,325 | Cardiocerebral resuscitation: a better approach to cardiac arrest. | To present a new approach to patients with cardiac arrest that improves neurologically normal survival. It is called cardiocerebral resuscitation (CCR), rather than cardiopulmonary resuscitation, as the major goal in cardiac arrest is to resuscitate the heart and the brain. CCR has three components: continuous chest compressions cardiopulmonary resuscitation for bystanders; a different Advanced Cardiac Life Support (ACLS) algorithm for Emergency Medical System; and a recently added aggressive postresuscitation care for resuscitated but comatose patients that includes therapeutic hypothermia and early catheterization/intervention.</AbstractText>Kellum et al. instituted the first two components of CCR in rural Wisconsin in 2004. In the subgroup of patients with a witnessed cardiac arrest and a shockable rhythm they found that neurological intact survival at hospital discharge was 15% the preceding 3 years, when the 2000 Guidelines were being followed, but 40% for the 3 years during CCR. Bobrow et al. instituted CCR for out-of-hospital cardiac arrest in metropolitan areas of Arizona and found a greater than 300% improvement (4.7-17.6%) in survival to hospital discharge of this subgroup of patients.</AbstractText>CCR improves survival of patients with cardiac arrest.</AbstractText> |
7,326 | Off-pump coronary bypass surgery for high-risk patients: only in expert centers? | Off-pump coronary artery bypass (OPCAB) grafting has been increasingly adopted in an effort to prevent deleterious effects of cardiopulmonary bypass, including the associated inflammatory response, global myocardial ischemia and the risks of aortic manipulation. In many studies, the greatest benefit of OPCAB has been in high-risk patients. This review will summarize the recent literature examining outcomes of OPCAB versus on-pump coronary artery bypass in high-risk subgroups, and will examine the safety of routine application of OPCAB in these patients.</AbstractText>Prospective randomized trials have shown that in comparison to on-pump coronary artery bypass, OPCAB reduces perioperative morbidity, but have failed to show a mortality benefit, owing to small sample sizes. However, numerous large retrospective series and meta-analyses have demonstrated a reduction in risk-adjusted mortality and morbidity with respect to the following outcomes: stroke, pulmonary function, renal function, atrial fibrillation, need for early reoperation, blood transfusion requirements, length of ICU and hospital stay, and hospital costs. An even greater benefit has been seen in the following high-risk patients: those with acute myocardial infarction, left ventricular dysfunction, previous history of stroke, renal insufficiency, women, elderly patients, and those undergoing reoperations.</AbstractText>Risk-adjusted outcomes are superior after OPCAB versus on-pump coronary artery bypass for mortality and numerous morbidity endpoints. This benefit is most easily demonstrated in high-risk patient populations.</AbstractText> |
7,327 | [Tako-Tsubo syndrome after anaphylaxis caused by succinylcholine during general anaesthesia]. | The Tako-Tsubo syndrome (or transient left ventricular apical balloning) is a new clinical entity, very similar to acute myocardial infarction, but different by its excellent short-term prognosis. It has been reported after a physical or an emotional stress, and it is diagnosed by a coronary angiogram and a left ventriculography. We report here a case of Tako-Tsubo syndrome related to an anaphylactic shock caused by succinylcholine during general anaesthesia of a female patient, wearing an unadjustable gastric band. |
7,328 | Surgical therapies for post-myocardial infarction patients. | Occasionally, high-risk patients in the post-myocardial infarction (MI) period require surgical intervention for stabilization and/or revascularization. In a meta-analysis involving 3,088 patients with ischemic heart disease, revascularization was associated with nearly an 80% reduction in the risk of death. Coronary artery bypass graft (CABG) surgery is commonly performed in post-MI patients and is associated with more favorable outcomes than medical therapy. However, several factors have to be considered in proper patient selection for CABG, such as the left ventricular ejection fraction (LVEF), severity of heart failure (HF), and myocardial viability. The ongoing Surgical Treatment for Ischemic Heart Failure (STICH) trial will assess the benefits of CABG in patients with both a low LVEF and HF. Unstable post-MI patients who fail revascularization can be managed via mechanical circulatory support devices or pumps. These options significantly improve hemodynamic parameters. In addition, other surgical techniques, such as mitral valve repair, ventricular reconstruction surgery, and atrial fibrillation ablation, are being evaluated in patients with ischemic heart disease. |
7,329 | Intermittent hypoxia and sleep-disordered breathing: current concepts and perspectives. | There are three major types of sleep-disordered breathing (SDB) with respect to prevalence and health consequences, i.e. obstructive sleep apnoea syndrome (OSAS), Cheyne-Stokes respiration and central sleep apnoea (CSR-CSA) in chronic heart failure, and obesity hypoventilation syndrome (OHS). In all three conditions, hypoxia appears to affect body functioning in different ways. Most of the molecular and cellular mechanisms that occur in response to SDB-related hypoxia remain unknown. In OSAS, an inflammatory cascade mainly dependent upon intermittent hypoxia has been described. There is a strong interaction between haemodynamic and inflammatory changes in promoting vascular remodelling. Moreover, during OSAS, most organ, tissue or functional impairment is related to the severity of nocturnal hypoxia. CSR-CSA occurring during heart failure is primarily a consequence of cardiac impairment. CSR-CSA has deleterious consequences for cardiac prognosis and mortality since it favours sympathetic activation, ventricular ectopy and atrial fibrillation. Although correction of CSR-CSA seems to be critical, there is a need to establish therapy guidelines in large randomised controlled trials. Finally, OHS is a growing health concern, owing to the worldwide obesity epidemic and OHS morbidities. The pathophysiology of OHS remains largely unknown. However, resistance to leptin, obesity and severe nocturnal hypoxia lead to insulin resistance and endothelial dysfunction. In addition, several adipokines may be triggered by hypoxia and explain, at least in part, OHS morbidity and mortality. Overall, chronic intermittent hypoxia appears to have specific genomic effects that differ notably from continuous hypoxia. Further research is required to fully elucidate the molecular and cellular mechanisms. |
7,330 | Minimal interruption of cardiopulmonary resuscitation for a single shock as mandated by automated external defibrillations does not compromise outcomes in a porcine model of cardiac arrest and resuscitation. | Current automated external defibrillations require interruptions in chest compressions to avoid artifacts during electrocardiographic analyses and to minimize the risk of accidental delivery of an electric shock to the rescuer. The earlier three-shock algorithm, with prolonged interruptions of chest compressions, compromised outcomes and increased severity of postresuscitation myocardial dysfunction. In the present study, we investigated the effect of timing of minimal automated external defibrillation-mandated interruptions of chest compressions on cardiopulmonary resuscitation outcomes, using a single-shock algorithm. We hypothesized that an 8-sec interruption of chest compressions for a single shock, as mandated by automated external defibrillations, would not impair initial resuscitation and outcomes of cardiopulmonary resuscitation.</AbstractText>Randomized prospective animal study.</AbstractText>University affiliated research laboratory.</AbstractText>Domestic pigs.</AbstractText>In 24 domestic male pigs weighing 41 +/- 2 kg, ventricular fibrillation was induced by left anterior descending coronary artery occlusion and untreated for 7 min. Cardiopulmonary resuscitation, including chest compressions and ventilation with oxygen, was then performed for an interval of 2 min before attempted defibrillation. Animals were randomized into three groups: A) interruption immediately before defibrillation; B) interruption after 1 min of cardiopulmonary resuscitation; or C) no interruption. Chest compressions were delivered with the aid of a mechanical chest compressor at a rate of 100 compressions/min and compression/ventilation ratio of 30:2. Defibrillation was attempted with a single biphasic 150-J shock. Each animal was successfully resuscitated and survived for >72 hr. No differences in the number of shocks before return of spontaneous circulation, frequency of recurrent ventricular fibrillation, duration of cardiopulmonary resuscitation, and severity of postresuscitation myocardial dysfunction were observed.</AbstractText>In this experimental model of cardiac arrest and cardiopulmonary resuscitation, minimal automated external defibrillation-mandated interruption of chest compressions for a single-shock algorithm did not have adverse effects on postresuscitation myocardial or neurologic function. All animals, whether subjected to cardiopulmonary resuscitation interruptions or not, survived.</AbstractText> |
7,331 | Milrinone use is associated with postoperative atrial fibrillation after cardiac surgery. | Postoperative atrial fibrillation (AF), a frequent complication after cardiac surgery, causes morbidity and prolongs hospitalization. Inotropic drugs are commonly used perioperatively to support ventricular function. This study tested the hypothesis that the use of inotropic drugs is associated with postoperative AF.</AbstractText>We evaluated perioperative risk factors in 232 patients who underwent elective cardiac surgery. All patients were in sinus rhythm at surgery. Sixty-seven patients (28.9%) developed AF a mean of 2.9+/-2.1 days after surgery. Patients who developed AF stayed in the hospital longer (P<0.001) and were more likely to die (P=0.02). Milrinone use was associated with an increased risk of postoperative AF (58.2% versus 26.1% in nonusers; P<0.001). Older age (63.4+/-10.7 versus 56.7+/-12.3 years; P<0.001), hypertension (P=0.04), lower preoperative ejection fraction (P=0.03), mitral valve surgery (P=0.02), right ventricular dysfunction (P=0.03), and higher mean pulmonary artery pressure (27.1+/-9.3 versus 21.8+/-7.5 mm Hg; P=0.001) also were associated with postoperative AF. In multivariable logistic regression, age (P<0.001), ejection fraction (P=0.02), and milrinone use (odds ratio, 4.86; 95% confidence interval, 2.31 to 10.25; P<0.001) independently predicted postoperative AF. When only data from patients with pulmonary artery catheters were analyzed and pulmonary artery pressure was included in the model, age, milrinone use (odds ratio, 4.45; 95% confidence interval, 2.01 to 9.84; P<0.001), and higher pulmonary artery pressure (P=0.02) were associated with an increased risk of postoperative AF. Adding other potential confounders or stratifying analysis by mitral valve surgery did not change the association of milrinone use with postoperative AF.</AbstractText>Milrinone use is an independent risk factor for postoperative AF after elective cardiac surgery.</AbstractText> |
7,332 | Standardization of video-assisted cardiac surgery technique: initial experience. | Minimally invasive cardiac surgery has been performed in major worldwide centers, including procedure such as valves, coronary and congenital surgery.</AbstractText>To demonstrate our first works with noninvasive cardiac surgery by mean of the experience gained with general and thoracic surgery.</AbstractText>Whenever possible to carry out a minimally invasive cardiac surgery, this was the approach of choice. The left thoracoscopy was used in four cases: (1) symptomatic coronary-pulmonary fistula ligation; (2) implant of an epicardial electrode into the left ventricle for resynchronization; (3) excision of pericardial giant lipoma in the left atrium, and (4) resection of hemangiolipoma in the mediastinum. Right thoracoscopy with extracorporeal circulation through cardiopulmonary bypass via femoral vein and artery and cardiac arrest in ventricular fibrillation with moderate hypothermia were carried out in the following cases: (5) patient with mitral stenosis after surgical repair with Carpentier ring 12 years before. An anterior and posterior commissurotomy without thoracotomy was successfully made; (6) patient with idiopathic dilated cardiomyopathy, high-response atrial fibrillation, and severe mitral insufficiency, underwent mitral repair surgery with Gregori's ring and ablation of the pulmonary veins with radio-frequency catheter. (MAZZE modified).</AbstractText>No death occurred in this series and the surgical result in all cases was highly satisfactory. All patients were discharged from hospital with a mean time of 5.5 +/- 5 days after intervention.</AbstractText>Our initial experience in this field proves the effectiveness and the viability in introducing this type of technique.</AbstractText> |
7,333 | Right ventricular dilatation predicts survival after mitral valve repair in patients with impaired left ventricular systolic function. | The prognostic value of the right ventricular parameters in patients with heart failure (HF) is well documented, but the data on patients undergoing mitral valve repair are lacking.</AbstractText>The association between pre-operative right ventricular dilatation and outcome was studied in 70 consecutive patients with HF who underwent elective mitral valve repair. Mean age was 67 years, 71% were men, mean pre-operative NYHA class was 2.8, mean pre-operative ejection fraction was 31%, and 47% had atrial fibrillation. The ischaemic cardiomyopathy (ICM) was the cause of HF in 32% of the patients. Perioperative mortality was 7.1% by a median logistic Euroscore of 7.5 (range 1.3-47.5). During a mean follow-up of 887 days, 35% of the patients reached the combined endpoint of overall mortality or transplantation. Reoperation was performed in four patients. One and 3 years survival rates were 88% and 72%, respectively. By multivariate Cox analysis, right ventricular dilatation, ICM, and age significantly predicted the outcome.</AbstractText>Right ventricular dilatation is an important modulator of outcome in patients with HF and mitral regurgitation.</AbstractText> |
7,334 | The effects of nifekalant hydrochloride on the QT dispersion after direct-current defibrillation. | Although nifekalant hydrochloride (NIFE) has been demonstrated to suppress ventricular tachyarrhythmia, especially electrical storm, the mechanism by which it does so is still unclear. We examined its effects on the spatial dispersion of repolarization (SDR) after implantable cardioverter-defibrillator (ICD) shock.</AbstractText>In twenty five patients with an ICD, we recorded the 87-lead ECG during sinus rhythm (the CONTROL group) under general anesthesia, after NIFE administration alone, and just after termination of induced ventricular fibrillation (VF) by ICD shock with or without NIFE administration. In all recordings, the corrected QT interval (QTc) was measured in each lead. The dispersion of QTc (QTc-D; maximum QTc minus minimum QTc) was also measured. Compared with the CONTROL, the QTc-D exhibited significant deterioration after ICD shock (61 +/- 12, 91 +/- 24 ms(1/2), respectively, p < 0.001). However, the QTc-D after NIFE administration either with or without ICD shock did not differ from the CONTROL group (65 +/- 20, 61 +/- 18, and 61 +/- 12 ms(1/2), respectively, p = 0.99).</AbstractText>NIFE suppressed the deterioration of SDR by ICD shock. This might be a mechanism by which NIFE suppresses recurrence of ventricular tachyarrhythmia after ICD shock.</AbstractText> |
7,335 | Aortic stenosis: diagnosis and treatment. | Aortic stenosis is the most important cardiac valve disease in developed countries, affecting 3 percent of persons older than 65 years. Although the survival rate in asymptomatic patients with aortic stenosis is comparable to that in age- and sex-matched control patients, the average overall survival rate in symptomatic persons without aortic valve replacement is two to three years. During the asymptomatic latent period, left ventricular hypertrophy and atrial augmentation of preload compensate for the increase in afterload caused by aortic stenosis. As the disease worsens, these compensatory mechanisms become inadequate, leading to symptoms of heart failure, angina, or syncope. Aortic valve replacement should be recommended in most patients with any of these symptoms accompanied by evidence of significant aortic stenosis on echocardiography. Watchful waiting is recommended for most asymptomatic patients, including those with hemodynamically significant aortic stenosis. Patients should be educated about symptoms and the importance of promptly reporting them to their physicians. Serial Doppler echocardiography is recommended annually for severe aortic stenosis, every one or two years for moderate disease, and every three to five years for mild disease. Cardiology referral is recommended for all patients with symptomatic aortic stenosis, those with severe aortic stenosis without apparent symptoms, and those with left ventricular dysfunction. Many patients with asymptomatic aortic stenosis have concurrent cardiac conditions, such as hypertension, atrial fibrillation, and coronary artery disease, which should also be carefully managed. |
7,336 | Nerve sprouting suppresses myocardial I(to) and I(K1) channels and increases severity to ventricular fibrillation in rat. | Nerve sprouting in healed myocardial infarction has been associated with increased incidences of ventricular tachyarrhythmia and sudden cardiac death. However, the underlying electrophysiological mechanisms are unclear. To investigate the linkage between nerve sprouting and potassium channel function, we developed a rat model of cardiac sympathetic nerve sprouting by chronic subcutaneous injection of 4-methylcatechol, a potent stimulator of nerve growth factor (NGF) synthesis. Cardiac sympathetic nerves were visualized by immunohistochemical staining. Myocardial necrotic injury was created by focal cold shock across intact diaphragm to mimic infarction. Transient outward current (I(to)) and inward rectifier current (I(K1)) of cardiomyocytes were recorded with the whole-cell patch clamp technique. We found that chronic 4-MC administration 1) increased cardiac NGF level and the density of cardiac sympathetic innervation; 2) decreased the expressions of Kv4.2, Kv channel-interacting protein 2 (KChIP2), Kir2.1, and the current densities of I(to) and I(K1); 3) reduced the phosphorylation of extracellular signal-regulated kinase 1/2 (pERK1/2); and 4) decreased heart rate variability and increased the susceptibility to ventricular fibrillation. Myocardial necrotic injury exerted similar effects as 4-methylcatechol, and 4-methylcatechol plus myocardial necrotic injury intensified the cardiac effects of 4-methylcatechol alone and decreased the phosphoralation of cAMP response element-binding protein (CREB). We conclude that nerve sprouting suppressed the expressions and functions of myocardial I(to) and I(K1) channels and increased the susceptibility to ventricular fibrillation. These effects are associated with decreased phosphorylation of ERK and CREB and reduced expression of KChIP2. |
7,337 | Where do derived precordial leads fail? | A 12-lead electrocardiogram (ECG) reconstructed from a reduced subset of leads is desired in continued arrhythmia and ST monitoring for less tangled wires and increased patient comfort. However, the impact of reconstructed 12-lead lead ECG on clinical ECG diagnosis has not been studied thoroughly. This study compares the differences between recorded and reconstructed 12-lead diagnostic ECG interpretation with 2 commonly used configurations: reconstruct precordial leads V(2), V(3), V(5), and V(6) from V(1),V(4), or reconstruct V(1), V(3), V(4), and V(6) from V(2),V(5). Limb leads are recorded in both configurations. A total of 1785 ECGs were randomly selected from a large database of 50,000 ECGs consecutively collected from 2 teaching hospitals. ECGs with extreme artifact and paced rhythm were excluded. Manual ECG annotations by 2 cardiologists were categorized and used in testing. The Philips resting 12-lead ECG algorithm was used to generate computer measurements and interpretations for comparison. Results were compared for both arrhythmia and morphology categories with high prevalence interpretations including atrial fibrillation, anterior myocardial infarct, right bundle-branch block, left bundle-branch block, left atrial enlargement, and left ventricular hypertrophy. Sensitivity and specificity were calculated for each reconstruction configuration in these arrhythmia and morphology categories. Compared to recorded 12-leads, the V(2),V(5) lead configuration shows weakness in interpretations where V(1) is important such as atrial arrhythmia, atrial enlargement, and bundle-branch blocks. The V(1),V(4) lead configuration shows a decreased sensitivity in detection of anterior myocardial infarct, left bundle-branch block (LBBB), and left ventricular hypertrophy (LVH). In conclusion, reconstructed precordial leads are not equivalent to recorded leads for clinical ECG diagnoses especially in ECGs presenting rhythm and morphology abnormalities. In addition, significant accuracy reduction in ECG interpretation is not strongly correlated with waveform differences between reconstructed and recorded 12-lead ECGs. |
7,338 | [Atrial fibrillation. Monitoring of rhythm versus monitoring of ventricular response]. | Atrial fibrillation is the most frequent supraventricular arrhythmia. The goals for the treatment of this arrhythmia are symptom control and reducing cardiovascular morbidity and mortality. In elderly patients with no symptoms we must indicate therapy based on rate control. On the other side, in young patients without heart disease, those very symptomatic or if atrial fibrillation causes a significant hemodynamic and functional deterioration we must try, at least initially, a strategy of maintaining sinus rhythm. In the future, we hope that the development of new anti-arrhythmic drugs safer and more effective, and refining catheter ablation will lead to increased therapeutic efficacy in patients with atrial fibrillation. |
7,339 | Ventricular arrhythmia onset during diagnostic coronary angiography with a 5F or 4F universal catheter. | Of 18,365 patients who underwent coronary angiography with a 4F or 5F universal catheter between April 2004 and May 2007, 24 (0.131%) experienced sustained ventricular tachycardia or ventricular fibrillation during the procedure. There was no significant difference in any clinical or angiographic characteristic between patients who had a ventricular arrhythmia and those who did not. Of the 24 episodes of ventricular arrhythmia, 14 were related to catheter manipulation, 8 to ischemia, and 2 to the contrast medium, while the cause could not be clearly established in 4. The incidence of ventricular arrhythmia with a universal catheter was 0.131%, and with a preformed catheter, 0.054% (P=.72). The study shows that serious ventricular arrhythmia occurs only rarely as a complication when coronary angiography is carried out using modern techniques and that imperfect manipulation of the catheter explains most episodes. |
7,340 | Management [corrected] of conversions to cardiopulmonary bypass in beating heart coronary surgery. | This study investigated outcomes in patients undergoing coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), who needed conversion to CPB. Between September, 1998 and September, 2003, 1000 CABG procedures were performed in a Cardiovascular Clinic, University Clinical Centre Tuzla. Multivessel CABG were selected arbitrarily for CABG without CPB (OPCAB) or CABG with CPB (ONCAB). Patients who required conversion due to technical difficulty with grafting were performed with ONCAB including cardioplegic arrest. Patients with severe hemodynamic instability and cardiac arrest were performed as ONCAB without crossclamping, while patients converted for mild to moderate hemodynamic instability were given cardioplegic arrest or not, depending on surgeon preference. 493 operations were scheduled and performed as ONCAB (49.3%), 468 as OPCAB (46.8%) and 39 originally scheduled OPCAB operations were converted to ONCAB (7.7% of originally scheduled OPCAB patients or 3.9% of total number of CABG). Reasons for conversions were: mild to severe hemodynamic instability--28 (71.8%); poor vessels or difficult graft revision--11 (28.2%). Patients converted because of technical difficulty or mild hemodynamic instability behaved as regular ONCAB patients. In the 9 patients who were emergently converted due to cardiac arrest or ventricular fibrillation, 3 patients had stroke and 3 severe myocardial ischemia requiring intraaortic balloon pump. It is of great importance to keep conversions to CPB due to cardiac arrest at a low level. The serious complications seen in such patients can significantly impede the overall benefits of a successful OPCAB program. |
7,341 | Thyrotoxicosis-induced ventricular arrhythmias. | Cardiac arrhythmias associated with thyrotoxicosis tend to be supraventricular in nature with atrial fibrillation being the most common. Ventricular arrhythmias are rarely associated with thyrotoxicosis and are considered to be secondary to intrinsic cardiac disease.</AbstractText>We present three patients with thyrotoxicosis and stable coronary disease in whom the primary cardiac rhythm disturbance was ventricular tachycardia. In all of these patients, the ventricular arrhythmias terminated with achievement of a euthyroid state. We hypothesize that the thyrotoxic state contributed to the etiology of, or lowered the threshold for the ventricular arrhythmias.</AbstractText>Prompt attention to the management of thyrotoxicosis in patients with a history of significant heart disease is warranted in order to avoid potentially fatal arrhythmias.</AbstractText> |
7,342 | Ventricular arrhythmia in children: diagnosis and management. | With increasing awareness of genetic abnormalities and the aging of patients with structural cardiac disease, particularly those who have had cardiac surgery, primary ventricular tachycardia is being recognized more frequently in children and adolescents and is becoming a larger management issue. The distinction of primary versus secondary is based on whether ventricular tachycardia is the inciting arrhythmia or the end result of a prolonged ischemic event, such as prolonged bradycardia with resultant ventricular tachycardia. This article discusses only primary ventricular tachycardia. The incidence clearly increases with age after cardiac surgery, particularly in specific cardiac abnormalities, such as tetralogy of Fallot post repair, transposition of the great arteries, post atrial switch operation, and hypertrophic obstructive cardiomyopathy. In addition, as genetic abnormalities are becoming better appreciated, conditions such as long QT syndrome, arrhythmogenic right ventricular cardiomyopathy, and Brugada syndrome, with their risk for ventricular tachycardia and fibrillation, are being seen increasingly in the pediatric population. Long-term treatment of ventricular tachycardia includes drug therapy, implantable device therapy, invasive ablation therapy, and combinations of these modalities. To choose the appropriate therapy, the clinician must consider the arrhythmia's effect on the patient's hemodynamic status and the potential for sudden cardiac death. |
7,343 | Optimal Programming of ICDs for Prevention of Appropriate and Inappropriate Shocks. | Expansion of indications for implantable cardioverter-defibrillators (ICDs) has led to a significant increase in the number of patients receiving ICDs and the number of lives saved because of ICD therapy. However, appropriate or inappropriate shocks are frequent and may result in a significant decrease in quality of life in patients with ICDs. Atrial fibrillation with rapid ventricular response, sinus tachycardia, atrial tachycardia or atrial flutter with rapid conduction, and other supraventricular tachycardias are the most common arrhythmias causing inappropriate therapy. Other causes include oversensing of diaphragmatic potentials or myopotentials, T-wave oversensing, double or triple counting of intracardiac signals, lead fractures or header connection problems, lead chatter or noise, and electromagnetic interference. Strategies to reduce inappropriate therapy using device programming rely on the ability to distinguish supraventricular and atrial arrhythmias from ventricular tachycardia. Avoiding therapy for nonsustained ventricular arrhythmias and increasing the role of antitachycardia pacing to terminate ventricular tachycardia are key approaches to reducing shocks for ventricular arrhythmias. Optimal programming holds great promise for decreasing the overall incidence of shock therapy and increasing ICD acceptance. |
7,344 | Cardiac arrest management: part 1. Understanding the role of Basic Life Support in the latest American Heart Association guidelines. | You've just finished renewing your CPR card at the firehouse, and now you're sitting in the day room with your classmates. One of them is frustrated that the guidelines keep changing. "First it's five compressions to one breath," he says. "Then it's 15 to two, and now 30 to two. And what about shocking first? They just can't seem to make up their minds." You liked the class, but you can't help thinking about all the cardiac arrests you've been on over the years. For all the changes in CPR and the new toys and drugs paramedics use now, very few patients seem to get pulses back and walk out of the hospital. You wonder if things will change with the new guidelines. |
7,345 | Anticoagulant and/or antiplatelet treatment in patients with atrial fibrillation after percutaneous coronary intervention. A single-center experience. | Atrial fibrillation (AF) is the most common cardiac arrhythmia sustained and frequently occurs in patients with coronary heart disease. Thus, a large number of patients requiring percutaneous coronary intervention (PCI) also suffer from AF. An anticoagulant regimen has not been standardized for patients with AF after coronary stent implantation.</AbstractText>The authors investigated data from 159 patients with AF who underwent PCI in their department. Baseline variables and incidence of a combined endpoint (stroke, myocardial infarction, cardiovascular death, severe bleeding) were compared in patients receiving clopidogrel and acetylsalicylic acid (ASA; group 1) versus patients receiving the combination of clopidogrel and ASA with low-molecular-weight heparin (LMWH; group 2) versus patients receiving the combination of clopidogrel and ASA with oral anticoagulation (OAC; group 3) at discharge.</AbstractText>Patients discharged with triple therapy including OAC seemed to be at higher risk: patients in group 3 had decreased left ventricular ejection fraction and increased inflammatory state as measured by plasma fibrinogen and C-reactive protein. Moreover, previous OAC treatment and strokes were found more often in this subgroup of patients. In a median follow-up of 1.4 years, two severe bleeding events (both in group 1), four myocardial infarctions (all in group 1), 13 strokes (nine in group 1, four in group 2), and nine cardiovascular deaths (three in group 1, five in group 2, one in group 3) occurred.</AbstractText>In this analysis, no treatment regimen seemed to be clearly superior. It underlines the importance of prospective, randomized trials to investigate the optimal antithrombotic/antiplatelet treatment for patients with AF after PCI.</AbstractText> |
7,346 | Ventricular fibrillation time constant for swine. | The strength-duration curve for cardiac excitation can be modeled by a parallel resistor-capacitor circuit that has a time constant. Experiments on six pigs were performed by delivering current from the X26 Taser dart at a distance from the heart to cause ventricular fibrillation (VF). The X26 Taser is an electromuscular incapacitation device (EMD), which generates about 50 kV and delivers a pulse train of about 15-19 pulses s(-1) with a pulse duration of about 150 micros and peak current about 2 A. Similarly a continuous 60 Hz alternating current of the amplitude required to cause VF was delivered from the same distance. The average current and duration of the current pulse were estimated in both sets of experiments. The strength-duration equation was solved to yield an average time constant of 2.87 ms +/- 1.90 (SD). Results obtained may help in the development of safety standards for future electromuscular incapacitation devices (EMDs) without requiring additional animal tests. |
7,347 | Regional variation in out-of-hospital cardiac arrest incidence and outcome. | The health and policy implications of regional variation in incidence and outcome of out-of-hospital cardiac arrest remain to be determined.</AbstractText>To evaluate whether cardiac arrest incidence and outcome differ across geographic regions.</AbstractText><AbstractText Label="DESIGN, SETTING, AND PATIENTS" NlmCategory="METHODS">Prospective observational study (the Resuscitation Outcomes Consortium) of all out-of-hospital cardiac arrests in 10 North American sites (8 US and 2 Canadian) from May 1, 2006, to April 30, 2007, followed up to hospital discharge, and including data available as of June 28, 2008. Cases (aged 0-108 years) were assessed by organized emergency medical services (EMS) personnel, did not have traumatic injury, and received attempts at external defibrillation or chest compressions or resuscitation was not attempted. Census data were used to determine rates adjusted for age and sex.</AbstractText>Incidence rate, mortality rate, case-fatality rate, and survival to discharge for patients assessed or treated by EMS personnel or with an initial rhythm of ventricular fibrillation.</AbstractText>Among the 10 sites, the total catchment population was 21.4 million, and there were 20,520 cardiac arrests. A total of 11,898 (58.0%) had resuscitation attempted; 2729 (22.9% of treated) had initial rhythm of ventricular fibrillation or ventricular tachycardia or rhythms that were shockable by an automated external defibrillator; and 954 (4.6% of total) were discharged alive. The median incidence of EMS-treated cardiac arrest across sites was 52.1 (interquartile range [IQR], 48.0-70.1) per 100,000 population; survival ranged from 3.0% to 16.3%, with a median of 8.4% (IQR, 5.4%-10.4%). Median ventricular fibrillation incidence was 12.6 (IQR, 10.6-5.2) per 100,000 population; survival ranged from 7.7% to 39.9%, with a median of 22.0% (IQR, 15.0%-24.4%), with significant differences across sites for incidence and survival (P<.001).</AbstractText>In this study involving 10 geographic regions in North America, there were significant and important regional differences in out-of-hospital cardiac arrest incidence and outcome.</AbstractText> |
7,348 | Focal AF-ablation after pulmonary vein isolation in a patient with hypertrophic cardiomyopathy using cryothermal energy. | A 42-year-old man, with a history of hypertrophic cardiomyopathy (HCM), an electrocardiogram pattern of ventricular preexcitation typical for mutations in the PRKAG2 gene, and highly symptomatic paroxysmal drug-resistant atrial fibrillation (AF), underwent successful circumferential isolation of his pulmonary veins using a 28-mm double lumen cryoballoon. Because AF was still inducible with programmed stimulation, fractionated signals were targeted in the left atrium with a conventional cryocatheter. Ablation of an endocardial focus with fractionated potentials at the base of the left appendage terminated the episode and rendered AF noninducible. No recurrence of AF was observed during a 10-month follow-up period. |
7,349 | Risk factors for atrioventricular tachycardia degenerating to atrial flutter/fibrillation in the young with Wolff-Parkinson-White. | Atrioventricular reciprocating tachycardia (AVRT) is common in patients (pts) with Wolff-Parkinson-White (WPW) syndrome but atrial flutter/fibrillation (AF) with rapid ventricular response (RVR) is rare. Although AF occurs in 18% of adult WPW pts, its incidence in children is unknown. We sought to determine risk factors for AVRT spontaneously degenerating to AF during electrophysiologic studies (EPS) in children with WPW.</AbstractText>This was a retrospective study of children with WPW referred for accessory pathway (AP) ablation without clinical AF. Standard electrophysiologic protocols were performed to induce AVRT. To determine if AF degeneration was associated with patient characteristics, 2-sample t-tests, Chi-square, and Fisher's exact were used.</AbstractText>There were 53 (31 males) WPW pts studied. During EPS, AVRT degenerated to AF in 27/53 (51%). RVR was seen in 18/27 (67%) patients. The ventricular cycle length (CL) during AF was shorter with RVR (211 + 24 ms) than without (313 + 65 ms) (P = 0.01). AF occurred more commonly among patients with right anterior AP (P = 0.05). Patient gender, age, height, weight, body surface area, persistence of preexcitation on exercise testing, baseline CL, AVRT conduction, and AP number were not significant AF determinants. The AVRT CL was significantly shorter in patients with (265.2 + 41.5 ms) versus those without (308 + 59 ms) AF (P = 0.01). Preliminary data suggest that AP location may be related to patient ethnicity.</AbstractText>AF with RVR occurred following AVRT induction during EPS in 34% of our WPW patients, typically associated with right-sided AP locations. Time intervals for RVR to degenerate into ventricular fibrillation and lead to SCD are yet to be determined.</AbstractText> |
7,350 | Hemodynamics and prognosis after primary cardiac resynchronization system implantation compared to "upgrade" procedures. | Left bundle brunch block (LBBB) and right ventricular stimulation (RVS) may be associated with asynchrony and heart failure. Differences between these two entities and their response to cardiac resynchronization therapy (CRT) are not well defined.</AbstractText>Patients receiving CRT from 1999 to 2006 were analyzed for cardiac events and prognosis separated between primary implants for LBBB (n = 221) and upgrades from RVS (n = 107). A subgroup of 105 patients (LBBB = 69; RVS = 36) was studied in more detail (New York Heart Association [NYHA], quality of life, brain natriuretic peptide, peak VO2, left ventricular ejection fraction [LVEF], wedge pressure, Cardiac Index, QRS, left-right preejection period using pulsed wave doppler, septum-lateral wall motion delay using tissue doppler imaging) at baseline and after 1 year.</AbstractText>Age (68.4 +/- 11 years vs 68.7 +/- 15 years, n. s.), NYHA class (3.1 vs 3.1, n. s.), LVEF (26.4 vs 28.1, n. s.), and clinical parameters were comparable between LBBB and RVS. The latter group consisted of more patients with chronic atrial fibrillation (14% vs 37%, P = 0.03). After 1 year, NYHA class (-0.8 +/- 0.8 vs -0.6 +/- 0.8, n. s.), LVEF (+13.7 +/- 14% vs +8.7 +/- 10%, n. s.), and clinical parameters improved similarly. After a median follow-up of 2.33 +/- 1.8 years in the LBBB versus 2.43 +/- 1.9 years in the RVS group, there was no difference in long-term prognosis or cardiac events in the total cohort (5-year event rate, 53% vs 55%, P = n. s.).</AbstractText>Upgrade patients showed similar baseline parameters and response to CRT as to primary implants. No difference in events or long-term prognosis could be observed.</AbstractText> |
7,351 | Ventricular arrhythmias after left ventricular assist device implantation. | Left ventricular assist devices (LVADs) have been used as a bridge to cardiac transplantation and as destination therapy in patients with advanced heart failure. The period after LVAD support is associated with ventricular arrhythmias (VAs) despite ventricular unloading and such VAs can have a detrimental effect on survival. Despite the increasing use of LVAD, little is known regarding post-LVAD VAs at the molecular level and in vivo.</AbstractText>Forty-two patients who received LVAD over a 24-month period were evaluated and grouped on the basis of the presence or absence of VAs during LVAD support. We completed a comparative microarray analyses between six patients who developed ventricular tachycardia (VT) or ventricular fibrillation (VF) after LVAD support and six patients who did not develop VAs after LVAD.</AbstractText>VAs occurred in 15 patients (35.7%) during LVAD support at a median post-LVAD day of 25.2. VAs were strongly associated with nonusage of a beta-blocker post-LVAD (odds ratio of 7.04, P-value = 0.001). Analysis of a subset of patients who had VT or VF after LVAD placement showed a decrease in the expression of connexin 43 (0.48 +/- 0.07), Na+/K+-ATPase (0.60 +/- 0.05), and voltage-gated K+ channel Kv4.3 (0.42 +/- 0.04), and an increase in Na+/Ca2+ exchanger (2.2 +/- 0.4) and the structural genes: Titin (2.1 +/- 0.2), laminin (1.7 +/- 0.4), calsequestrin (1.8 +/- 0.5), skeletal muscle isoform of troponin T (5.1 +/- 0.9), and skeletal muscle isoform of troponin I (3.9 +/- 0.7).</AbstractText>After LVAD, the increased risk of VAs is strongly associated with nonusage of beta-blocker postoperatively.</AbstractText> |
7,352 | Timing of life-threatening arrhythmias detected by implantable cardioverter-defibrillators in relation to changes in cosmophysical factors. | Studies have linked the natural history of many pathologies with environmental physical activity. This study investigated the relationship between the occurrence of ventricular tachycardia/fibrillation (VT/VF) recorded by implantable cardioverter defibrillators (ICD) and geomagnetic and cosmic ray (neutron) activity.</AbstractText>The study group included 85 patients (73 men) with cardiomyopathy (80% ischemic) who underwent ICD placement in the years 1995-2006; 74% had a left ventricular ejection fraction of < 30%. Data on the days on which VT/VF occurred (total number of days: 284) and the days on which the patients were treated (total number of treatments: 580) were collected from the ICD records. The findings were analyzed against levels of geomagnetic activity (GMA) (I degree -IV degree) and cosmic ray activity (CRA), derived from international observatories, on the same days and throughout the study period.</AbstractText>On days of VT/VF, daily values of GMA level averaged 1.5 +/- 0.7, consistent with level I degree (quiet). The ratios of daily VT/VF episodes and treatment to GMA level for the whole study period were as follows: 1.2 level I; 0.9 level II; 0.69 level III; 0.78 level IV (r = -0.974; p = 0.02). Mean CRA on days of VT/VF was 9246.8 +/- 299.0 imp/min, and for all 4383 days studied, 8805.33 +/- 411.4 imp/min (p < 0.0001).</AbstractText>In patients with predominantly ischemic cardiomyopathy and severe left ventricular dysfunction, VT/VF occurs more often on days of low GMA and high CRA. Further studies are needed to determine the underlying mechanism of the effect of neutron activity on cardiac electrical instability.</AbstractText> |
7,353 | Ventricular fibrillation in a 5-year-old child on therapeutic dose of quinine dihydrochloride infusion for acute malaria. | Malaria is no doubt a disease of public health significance in the tropics. Plasmodium falciparum resistant to majority of the first-line antimalarial drugs now causes most of the infections treated in sub-Saharan Africa. Although there is increasing use of artemisinin-based combination therapy in many African nations, quinine still remains a commonly used drug for severe and chloroquine-resistant malaria. Cardiotoxicity associated with quinine has been largely reported. However, this was often more common with toxic doses. This case report is on a 5-year-old African Nigerian who was on treatment for uncomplicated malaria with quinine dihydrochloride infusion. All the laboratory investigations done were within normal limits except for positive blood films for malarial parasites. However, pre-treatment electrocardiographic evaluation of the patient was not carried out. She developed ventricular fibrillation and died less than one and a half hour into the quinine infusion. |
7,354 | The place of hybrid therapies with drugs to supplement nonpharmacological therapies in atrial fibrillation. | Atrial fibrillation (AF) is one of the most common cardiac arrhythmias, and its prevalence continues to rise as the aged population increases. Comparative studies of rhythm control and rate control have been equivocal; however, the benefits of rhythm control may have been offset by the limitations of antiarrhythmic drugs. More recently, nonpharmacological therapies have emerged that provide hope of more effective rhythm control. Catheter ablation techniques have gained favour with high success rates in specialized centers, although these techniques are not without complications and require considerable expertise. Pacing therapies designed to reduce harmful right ventricular pacing and increase physiological pacing have shown benefit in AF patients with bradycardia. Despite this progress, no single modality confers benefit for all patients. Strategies to combine these treatment modalities in a hybrid approach has shown increasing promise for subgroups of AF patients. |
7,355 | Cardiovascular effects of psychotropic drugs. | Cardiovascular disease is the leading cause of death in the general population and accounts for approximately 30% of all deaths; some of these are due to fatal arrhythmias, especially ventricular fibrillation. In a psychiatric population the prevalence of cardiovascular disease is higher than in the general population because of a different lifestyle and greater frequency of risks factors such as smoking, obesity, and increased stress. The increased prevalence of sudden death in this patient population has given rise to the question of drug-induced cardiovascular and arrhythmic effects. This article reviews the principal classes of psychotropic medications and their effects on the heart.</AbstractText>The review is based on Medline, Pubmed, Cochrane, and literature searches of publications from the period 1984 to 2005.</AbstractText>It is important for practitioners to be familiar with the possible effects of psychotropic medications on the cardiovascular system, especially in the elderly and other patients with preexisting cardiac problems. Before starting treatment with a new psychotropic medication, a careful history and physical are mandatory, and baseline liver, lipid, and kidney profiles as well as chest radiographic and electrocardiographic findings should be noted.</AbstractText> |
7,356 | Usefulness of echo-guided cardiac resynchronization pacing in patients undergoing "ablate and pace" therapy for permanent atrial fibrillation and effects of heart rate regularization and left ventricular resynchronization. | An acute comparative study of right ventricular (RV) pacing and echocardiographically guided cardiac resynchronization pacing (CRP) was performed in patients who underwent "ablate and pace" therapy for permanent atrial fibrillation. It was hypothesized that optimized CRP guided by tissue Doppler echocardiography would exert an additive beneficial hemodynamic effect to that of rate regularization achieved through atrioventricular junction ablation. An acute intrapatient comparison of echocardiographic parameters was performed between baseline preablation values and RV pacing and CRP (performed <24 hours after ablation) in 50 patients. Optimized CRP configuration was defined as the modality of pacing corresponding to that of the shortest intra-left ventricular (LV) delay among simultaneous biventricular pacing, sequential biventricular pacing, and single-chamber pacing. The intra-LV delay was defined as the difference between the longest and the shortest activation time in the six basal segments of the left ventricle. Compared with preablation measures, the ejection fraction increased by 10.8% during RV pacing (19% in patients with intra-LV delays <47.5 ms and 3% in those with intra-LV delays >47.5 ms). Compared with RV pacing, CRP caused a 9.2% increase in the ejection fraction, a 6.8% decrease in LV systolic diameter, and a 17.3% decrease in mitral regurgitation area; LV dyssynchrony was reduced from 52 +/- 27 to 21 +/- 12 ms. Similar results were observed in patients with and without depressed systolic function and in patients with and without left bundle branch block. In conclusion, rate regularization achieved through atrioventricular junction ablation and RV pacing provides a favorable hemodynamic effect that is inversely related to the level of LV dyssynchrony. Minimizing LV dyssynchrony by means of optimized CRP yields an additional important benefit. |
7,357 | Left atrial dyssynchrony assessed by strain imaging in predicting future development of atrial fibrillation in patients with heart failure. | The clinical and echocardiographic parameters associated with the risk of developing new onset atrial fibrillation (AF) in congestive heart failure (CHF) have not been studied comprehensively. We determined if dyssynchronous left atrial (LA) lengthening and contraction predicted future development of new onset AF in patients with CHF.</AbstractText>One hundred fifty-eight patients who were admitted for CHF without past or current AF were evaluated. We measured the time to peak velocity and time to peak strain with reference to the QRS complex during ventricular systole (reservoir) and late diastole (atrial contraction) in mid-portion of 4 LA walls. Dyssynchronous atrial lengthening and contraction (atrial dyssynchrony) was defined as the standard deviation of each parameter.</AbstractText>New onset AF developed in 21 patients (13.3%) after a mean follow-up of 43+/-15 months. Based on univariate Cox analysis, older age, larger LA dimension and volume index, lower LA fractional shortening, and the presence of atrial dyssynchrony were associated with new onset AF. In multivariate Cox analysis, atrial dyssynchrony based on strain (>39 ms, HR 10.0, p=0.003) and LA size (> or =45 mm, HR 4.3, p=0.016) were independent predictors of new onset AF in CHF.</AbstractText>We demonstrated that atrial dyssynchrony based on strain is the strongest univariate and multivariate predictor for new onset AF in hospitalized patients with CHF.</AbstractText> |
7,358 | To replace or not to replace: a systematic approach to respond to device advisories. | The decision of whether and when to replace a device in response to an "advisory" letter requires careful consideration, because device replacement carries related risks and is influenced by the clinical characteristics of the patient.</AbstractText>The risk/benefit of device replacement depends on four parameters: expected annual sudden cardiac death rate; residual device life; difference in failure rate between the device listed on the advisory letter and the replacement device; and the replacement procedure mortality risk. Using these four factors, we have developed an equation that provides the "number needed to replace" (NNR) to save one life. Per our model, patients implanted with a device with a failure rate approaching 1% and a probability of requiring device intervention >or=25% per year-in particular, pacemaker-dependent patients-have an NNR <250. Pacemaker-dependent patients, with devices having three or more years longevity, but with device failure rates >or=0.5%, have an NNR <100. Patients with arrhythmic risk <or=2.5% per year and those with devices having failure rates <0.1% have a high NNR and stand more risk to be harmed than benefited from device replacement.</AbstractText>Pacemaker-dependent patients and those with high arrhythmic risk (>or=25% annually) when having "advisory" devices with high failure rate (>or=1%) have an NNR <250 and, hence, could be considered for device replacement. Conversely, patients with arrhythmic risk <or=2.5% per year and those with devices having failure rates <or=0.1% have a high NNR or even risk of "harm" from device replacement. In all the intermediate cases, the NNR will quantify the benefit/risk ratio of replacement, thus helping physicians and patients decide on the preferred approach. The NNR methodology proposed here is also applicable to advisory notices issued to leads, but the high morbidity associated with lead replacement will generally rule out interventions to replace leads.</AbstractText> |
7,359 | Lambda-like ST segment elevation in acute myocardial infarction - a new risk marker for ventricular fibrillation? Three case reports. | Sudden cardiac death (SCD) is responsible for almost 50% of all cardiac deaths in the U.S. The most common underlying cause of SCD is coronary artery disease, especially acute myocardial infarction (AMI). There are no publications concerning the shape of ST segment elevation in AMI and the risk of ventricular fibrilation (VF) or SCD. We present three cases with AMI and atypical ST segment elevation - 'lambda-wave-like' pattern, complicated with episodes of VF. This ECG pattern resembles the ST segment elevation shape in the type 1C Brugada syndrome. The 'lambda-like' ST segment elevation in AMI may identify patients with increased risk of VF or SCD. |
7,360 | Rate-dependence of atrial tachycardia effects on atrial refractoriness and atrial fibrillation maintenance. | Although atrial-tachycardia remodelling is a significant atrial fibrillation (AF) promoting factor, little information is available about how atrial-tachycardia rate determines remodelling effects. This study assessed the effects of atrial tachypacing (ATP) over a range of clinically relevant rates on atrial electrophysiology and AF.</AbstractText>Chronically instrumented dogs underwent sequential 7 day ATP at 400, 300, 200, and 160 bpm in random order with 2 day recovery intervals between periods of ATP. ATP at 400, 300, and 200 bpm significantly decreased atrial effective refractory period (ERP) by 41 +/- 2, 37 +/- 3, and 7 +/- 1 ms, respectively, with no significant effects at 160 bpm. Mean duration of induced AF was increased by 400 and 300 bpm ATP (404 +/- 284 and 410 +/- 283 s on day 4, respectively, vs. 12 +/- 4 s at baseline, P < 0.01), but not by 200 or 160 bpm ATP. ATP effects developed slowly with 200 bpm pacing, so we studied 5 week ATP at 200 and 160 bpm in additional dogs. ERP shortened gradually over 3 weeks at 200 bpm (131 +/- 5 ms baseline vs. 112 +/- 4 and 105 +/- 4 ms at 2 and 3 weeks, respectively), but no decrease occurred thereafter (5-week value: 104 +/- 3 ms) and AF duration was not significantly affected. No change in ERP or AF duration occurred at 160 bpm. Because of the limited effects of 200 bpm ATP on AF duration despite significant effects on ERP, we tested 200 bpm ATP effects in the presence of AF substrates. When 200 bpm ATP was induced in the presence of a fibrotic AF substrate induced by 2 weeks of ventricular tachypacing followed by 1 week recovery, no change in AF duration or atrial vulnerability occurred. However, when 200 bpm ATP was followed by 400 bpm ATP, the onset of remodelling and AF duration increases was accelerated.</AbstractText>There is a non-linear relationship between atrial rate and the extent of atrial electrical remodelling. Remodelling at rates equivalent to paroxysmal supraventricular tachycardias in man is insufficient to promote AF alone or in the presence of an atrial fibrotic substrate, but can accelerate the remodelling and stabilization of AF when followed by faster atrial tachyarrhythmias.</AbstractText> |
7,361 | Prognostic factors and predictors of in-hospital mortality of patients with heart failure with preserved left ventricular ejection fraction. | To date, in-hospital mortality predictors of patients with heart failure and depressed left ventricular ejection fraction are well known. Nevertheless, this is not the case of patients suffering from heart failure with preserved left ventricular ejection fraction. Our aim is to describe the incidence and predictors of in-hospital mortality in patients during the first admission due to preserved left ventricular ejection fraction.</AbstractText>Seven hundred and seventy-one consecutive patients with a first admission to hospital due to preserved left ventricular ejection fraction between January 2002 and September 2003 comprised our study group. Cardiovascular risk factors, clinical, electrical and echocardiographic variables were studied. Univariate and multivariate logistic regression analysis was performed to obtain those factors independently associated with in-hospital mortality.</AbstractText>The mean age was 82.6 +/- 43.6 years (551 women, 66.3%). Variables in both groups were similar except for the history of ischaemic heart disease, dilated cardiomyopathy and the presence of normal sinus rhythm. Multivariate logistic regression analysis showed that a history of ischaemic heart disease, dilated cardiomyopathy and a cardiac rhythm different from normal sinus rhythm are associated with an increased in-hospital mortality.</AbstractText>Patients with preserved left ventricular ejection fraction have high in-hospital mortality during the first admission. A history of ischaemic heart disease, a history of dilated cardiomyopathy and the presence of a cardiac rhythm different from the normal sinus rhythm (atrial fibrillation or flutter or paced rhythm) are independent predictors of in-hospital mortality in these patients. These factors must especially be considered during the admission of such patients.</AbstractText> |
7,362 | Brain natriuretic peptide as a surrogate marker for cardioembolic stroke with paroxysmal atrial fibrillation. | Cardioembolic stroke generally results in severer disability, since it typically has a larger ischemic area than the other types of ischemic stroke. However, it is difficult to differentiate cardioembolic from noncardioembolic stroke (atherothrombotic and lacunar stroke), whenever ischemic stroke patients have sinus rhythm at the time of presentation.</AbstractText>In this study, we evaluated the levels of plasma brain natriuretic peptide in acute ischemic stroke patients with cardioembolic or noncardioembolic stroke and assessed whether this could provide a basis for differentiating cardioembolic stroke (especially due to paroxysmal atrial fibrillation) from noncardioembolic stroke. Our patient cohort consisted of 99 consecutive patients with acute cerebral infarction who were admitted to Kagawa University School of Medicine Hospital from January 1, 2005, to December 31, 2006. We excluded 23 patients with valve disease, heart failure, myocardial infarction or chronic renal failure. The mean age of the remaining 76 patients (51 males, 25 females) was 70.0 +/- 10.1 years.</AbstractText>Thirty-six patients had cardioembolic stroke with atrial fibrillation (including permanent and paroxysmal atrial fibrillation); the remaining 40 had noncardioembolic stroke. The plasma brain natriuretic peptide was evaluated on the first morning after admission in all patients. In cardioembolic stroke with atrial fibrillation (permanent and paroxysmal atrial fibrillation), the plasma brain natriuretic peptide, ratio of peak early filling velocity to peak atrial systolic velocity (E/A) and left atrial diameter were significantly increased (p < 0.001), and the left atrial appendage flow was significantly decreased (p < 0.001), compared with noncardioembolic stroke. Analyzed in those 4 factors, cardioembolic stroke was strongly predicted with >95% accuracy assessed by plasma brain natriuretic peptide and left atrial appendage flow.</AbstractText>From our results, it was suggested that the first-day brain natriuretic peptide and left atrial appendage flow measurements would be helpful in differentiating cardioembolic stroke with atrial fibrillation from noncardioembolic stroke.</AbstractText>Copyright 2008 S. Karger AG, Basel.</CopyrightInformation> |
7,363 | Lidocaine converts acute vagally associated atrial fibrillation to sinus rhythm in German Shepherd dogs with inherited arrhythmias. | Lidocaine is most frequently used to treat ventricular arrhythmias. However, lidocaine may have an antiarrhythmic effect for certain supraventricular arrhythmias.</AbstractText>We hypothesized that lidocaine would be effective in converting experimentally induced atrial fibrillation (AF) to sinus rhythm and that a decrease in the dominant frequency (DF) and an increase in the organization as judged by the spectral entropy (SE) would occur over the course of the conversion.</AbstractText>Seven German Shepherd (GS) Dogs.</AbstractText>Dogs were anesthetized with fentanyl and pentobarbital. AF was induced with standard pacing protocols while left and right atrial monophasic action potentials (MAP) were recorded. The power spectra from the MAP recordings were analyzed to determine DF and SE during treatment with boluses of 2 mg/kg lidocaine.</AbstractText>Lidocaine converted AF to sinus rhythm in all dogs and all episodes (n = 19). Conversion time was 27-87 seconds. After atropine, sustained AF was not induced; however, 5 episodes of atrial tachycardia resulted, and 3 were converted with lidocaine. Frequency domain analysis of 12 conversion sequences showed that left and right DF of the MAP signals decreased from the time of injection to conversion to sinus rhythm (P < .001). Mean SE indicated a gradient between the left and right atria (P = .003) that did not change during conversion.</AbstractText>Vagally associated AF in GS dogs is terminated with lidocaine. Lidocaine is likely an effective treatment in clinical dogs with vagally associated AF.</AbstractText> |
7,364 | Should amiodarone or lidocaine be given to patients who arrest after cardiac surgery and fail to cardiovert from ventricular fibrillation? | A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the administration of amiodarone or lidocaine in patients with refractory VT/VF after cardiac surgery results in successful cardioversion. Altogether more than 434 papers were found using the reported search, from which 23 articles were used to answer the clinical question. No randomized trials have been found in which amiodarone was studied in patients with refractory VF/VT after cardiac surgery. Recommendations on the use of amiodarone in patients with refractory VF/VT in both European and American 2005 Guidelines on Resuscitation are mainly based on expert consensus and are supported by a few randomized trials in patients with out-of-hospital cardiac arrest. We would therefore recommend that amiodarone is the first line drug that should be used in patients with refractory ventricular arrhythmias after cardiac surgery that persist after three failed attempts at cardioversion. Lidocaine should only be used if amiodarone is not available or if its use is contraindicated. Amiodarone should be administered as an intravenous bolus of 300 mg after the third unsuccessful shock. |
7,365 | The role of the renin angiotensin system blocking in the management of atrial fibrillation. | The objective of the study was to review the current available clinical evidence for the role of renin-angiotensin system (RAS) blockade in the treatment of atrial fibrillation (AF).</AbstractText>We conducted a Pubmed and Medline literature search (January 1980 through May 2007) to identify all clinical trials published in English involving the use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) for preventing the occurrence or recurrence of AF. Discussing pathophysiology and experimental evidence in detail is beyond the scope of this article.</AbstractText>There is no solid evidence to support using ACE inhibitors or ARBs as antiarrhythmic therapy in patients with AF. However, in view of the possible benefits and the low incidence of side effects with ACE inhibitors and ARBs, they might be given in patients with recurrent AF, particularly if there are other indications for their use such as hypertension, HF, or diabetes mellitus. Possible benefits from pre-treatment argue in favour of using ACE inhibitors and ARB as first-line therapy in patients with hypertension.</AbstractText> |
7,366 | GIANT Flutter Waves in ECG Lead V1: a Marker of Pulmonary Hypertension. | Atrial flutter (AFl) may exist with or without underlying structural heart disease. Typical AFl presents as a "sawtooth" pattern on the ECG - with inverted flutter (F) waves in the inferior leads and upright F waves in V1. This morphology offers no direct clues as to the underlying cardiac disorder, if any. Occasionally we have encountered giant F waves, most prominently in lead V1, reaching 5 mv or more in height - sometimes exceeding the QRS voltage. The significance of this pattern has not been investigated and reported on. To determine if giant F waves in V1 provide any insight into the presence/type/absence of specific underlying cardiac pathology, the history of 6 consecutive patients with giant F waves was reviewed. Upon review, the only factor common to each patient was the presence of or history of pulmonary hypertension. Right ventricular dilation and/or dysfunction and right atrial enlargement with or without tricuspid insufficiency were present in each by echocardiography. Giant F waves appear to occur in the setting of right heart dysfunction in patients with a history of or the continued presence of pulmonary hypertension. Their detection should indicate the need for right heart evaluation. |
7,367 | Survival after in-hospital cardiopulmonary resuscitation. | The use of postarrest variables to predict survival after discharge following in-hospital cardiopulmonary resuscitation has not been definitive. This study evaluates whether the duration of cardiopulmonary resuscitation (CPR) and other variables affect discharge rates and survival rates after discharge.</AbstractText>Prospective cohort survival data and arrest variables were collected, including initial observed rhythm, duration of CPR, time of arrest, and number of arrests. Arrests on unmonitored general medical units, monitored telemetry units, and critical care units were included. Outcome measures were: survival after CPR, 24 hours post-CPR, survival to discharge, and to six months postdischarge.</AbstractText>At both discharge and six months after discharge, ventricular fibrillation and ventricular tachycardia were associated with better survival rates than other initial rhythms (P < 0.001). There were significantly higher survival rates (P < 0.001) for those receiving CPR for < or =10 minutes as compared with those receiving CPR >10 minutes. Multiple versus single arrests and monitored versus unmonitored arrests approached significance. The time of day of the arrest was not a significant factor.</AbstractText>Duration of CPR >10 minutes was predictive of significantly decreased survival to discharge and six months postdischarge. Low six-month survival rates may reflect the relatively high proportion of initial rhythms other than ventricular in the study group.</AbstractText> |
7,368 | Programmed inappropriate ICD ventricular defibrillation for cardioversion of persistent atrial fibrillation. | In this report we briefly describe a patient with a dual chamber implantable cardioverter defibrillator in the context of severe ischemic cardiomyopathy who developed persistent atrial fibrillation. After appropriate anticoagulation and under mild sedation the patient was successfully cardioverted to sinus rhythm after a programmed ventricular synchronized defibrillation using his defibrillator. Programmed internal cardioversion of persistent atrial fibrillation in patients who have an implantable cardioverter defibillator without atrial defibrillation capabilities could be an effective and safe therapeutic option. Unlike external electrical cardioversion, this strategy does not interfere with the implantable cardioverter defibrillator, is more effective, and obviates the need of general anesthesia. This strategy should be further evaluated in clinical trials. |
7,369 | Update on cardiac arrhythmias in the ICU. | To explore recent findings on the treatment and outcome of cardiac arrhythmias and how they affect ICU activities.</AbstractText>The rate vs. rhythm control debate for the treatment of chronic atrial fibrillation continues. It is still unclear whether the postcardiac surgery inflammatory response contributes to the development of atrial fibrillation. In noncardiothoracic surgery/trauma patients hospitalized in an ICU, new-onset supraventricular arrhythmias are associated with markedly elevated mortality when compared with patients with a prior history of such arrhythmias and patients who do not develop arrhythmias. The onset of new supraventricular arrhythmias in such patients appears to be a manifestation of multiple system organ failure as it is closely associated with sepsis. Cardioversion of supraventricular arrhythmias with biphasic waveforms is being studied to determine whether it is more effective than cardioversion with monophasic waveforms.</AbstractText>Supraventricular arrhythmias, especially atrial fibrillation, occur frequently in ICU patients. Intensivists not only treat atrial fibrillation itself but also its complications and the complications of the therapies used to prevent these complications. In ICU patients, ventricular arrhythmias have ominous implications because they usually portend either a major cardiac or a systemic dysfunction or both.</AbstractText> |
7,370 | Connexin40 messenger ribonucleic acid is positively regulated by thyroid hormone (TH) acting in cardiac atria via the TH receptor. | Thyroid hormone (TH) regulates many cardiac genes via nuclear thyroid receptors, and hyperthyroidism is frequently associated with atrial fibrillation. Electrical activity propagation in myocardium depends on the transfer of current at gap junctions, and connexins (Cxs) 40 and 43 are the predominant junction proteins. In mice, Cx40, the main Cx involved in atrial conduction, is restricted to the atria and fibers of the conduction system, which also express Cx43. We studied cardiac expression of Cx40 and Cx43 in conjunction with electrocardiogram studies in mice overexpressing the dominant negative mutant thyroid hormone receptor-beta Delta337T exclusively in cardiomyocytes [myosin heavy chain (MHC-mutant)]. These mice develop the cardiac hypothyroid phenotype in the presence of normal serum TH. Expression was also examined in wild-type mice rendered hypothyroid or hyperthyroid by pharmacological treatment. Atrial Cx40 mRNA and protein levels were decreased (85 and 55%, respectively; P < 0.001) in MHC-mt mice. Atrial and ventricular Cx43 mRNA levels were not significantly changed. Hypothyroid and hyperthyroid animals showed a 25% decrease and 40% increase, respectively, in Cx40 mRNA abundance. However, MHC-mt mice presented very low Cx40 mRNA expression regardless of whether they were made hypothyroid or hyperthyroid. Atrial depolarization velocity, as represented by P wave duration in electrocardiograms of unanesthetized mice, was extremely reduced in MHC-mt mice, and to a lesser extent also in hypothyroid mice (90 and 30% increase in P wave duration). In contrast, this measure was increased in hyperthyroid mice (19% decrease in P wave duration). Therefore, this study reveals for the first time that Cx40 mRNA is up-regulated by TH acting in cardiac atria via the TH receptor and that this may be one of the mechanisms contributing to atrial conduction alterations in thyroid dysfunctions. |
7,371 | Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study. | Prognosis in patients suffering out-of-hospital cardiac arrest is poor. Higher survival rates have been observed only in patients with ventricular fibrillation who were fortunate enough to have basic and advanced life support initiated soon after cardiac arrest. An ability to predict cardiac arrest outcomes would be useful for resuscitation. Changes in expired end-tidal carbon dioxide levels during cardiopulmonary resuscitation (CPR) may be a useful, noninvasive predictor of successful resuscitation and survival from cardiac arrest, and could help in determining when to cease CPR efforts.</AbstractText>This is a prospective, observational study of 737 cases of out-of-hospital cardiac arrest. The patients were intubated and measurements of end-tidal carbon dioxide taken. Data according to the Utstein criteria, demographic information, medical data, and partial pressure of end-tidal carbon dioxide (PetCO2) values were collected for each patient in cardiac arrest by the emergency physician. We hypothesized that an end-tidal carbon dioxide level of 1.9 kPa (14.3 mmHg) or more after 20 minutes of standard advanced cardiac life support would predict restoration of spontaneous circulation (ROSC).</AbstractText>PetCO2 after 20 minutes of advanced life support averaged 0.92 +/- 0.29 kPa (6.9 +/- 2.2 mmHg) in patients who did not have ROSC and 4.36 +/- 1.11 kPa (32.8 +/- 9.1 mmHg) in those who did (P < 0.001). End-tidal carbon dioxide values of 1.9 kPa (14.3 mmHg) or less discriminated between the 402 patients with ROSC and 335 patients without. When a 20-minute end-tidal carbon dioxide value of 1.9 kPa (14.3 mmHg) or less was used as a screening test to predict ROSC, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100%.</AbstractText>End-tidal carbon dioxide levels of more than 1.9 kPa (14.3 mmHg) after 20 minutes may be used to predict ROSC with accuracy. End-tidal carbon dioxide levels should be monitored during CPR and considered a useful prognostic value for determining the outcome of resuscitative efforts and when to cease CPR in the field.</AbstractText> |
7,372 | The proinflammatory cytokine response following resuscitation in the swine model depends on the method of ventricular fibrillation induction. | A systemic inflammatory response has been reported following resuscitation from cardiac arrest. The purpose of this study was to compare the magnitude of the tumor necrosis factor-alpha (TNF-alpha) response in two different swine models of ventricular fibrillation (VF) arrest.</AbstractText>This was a randomized comparative trial conducted with domestic swine (N = 28, mean weight 40 kg, range 34-49 kg) of both genders. Anesthetized and instrumented swine were randomized to electrically induced VF (n = 14) or spontaneous VF induced by occlusion of a coronary artery (n = 14). After 8 minutes of VF, countershocks were given and standard advanced cardiac life support was initiated. Resuscitated animals were observed for 3 hours, and hemodynamics, base excess, and TNF-alpha concentrations were measured at intervals.</AbstractText>TNF-alpha concentrations were significantly greater in the ischemic VF group throughout the postresuscitation period. Multivariate modeling demonstrated that the TNF-alpha level was dependent on the method of VF induction and correlated with ischemia time (untreated VF period plus time to restoration of circulation) and the degree of postresuscitation hypoperfusion as reflected in base excess measurements.</AbstractText>This study demonstrates that TNF-alpha concentrations increase after resuscitation from cardiac arrest and that the TNF-alpha response is more profound in animals subjected to ischemic, spontaneous VF. The observed differences may be due to a longer resuscitation time and persistent postresuscitation hypoperfusion in the ischemic VF group. These differences need to be considered in studies evaluating mechanisms of postresuscitation organ dysfunction and defining mortality markers.</AbstractText> |
7,373 | Influence of intracoronary shunt on myocardial damage: a prospective randomized study. | We aimed to evaluate whether surgical intracoronary shunt protects myocardium in patients with moderate left ventricular dysfunction (MLVD).</AbstractText>Thirty-nine patients consisted the shunt group and 43 patients consisted the shuntless group. Troponin I, CK, and CK-MB were measured preoperatively, and at 6 and 24h postoperatively. Cardiac enzymes, rate of postoperative atrial fibrillation (AF) and third month ejection fraction (EF) were compared between the groups.</AbstractText>There were no significant differences between the groups for preoperative troponin I, CK, CK-MB, and postoperative CK levels (at 6 and 24h). Postoperative troponin I and CK-MB levels were significantly lower in the shunt group (p<0.001). Although preoperative EF of the patients were not significantly different between groups, the third month EF were significantly increased in both groups, and this increment was significantly higher in the shunt group than the shuntless group. One patient (2.3%) died in the shuntless group whereas there was no death in the shunt group.</AbstractText>Intracoronary shunt has protective effects on myocardium in patients with moderate left ventricular dysfunction.</AbstractText> |
7,374 | Ischaemic preconditioning during cardiac surgery: systematic review and meta-analysis of perioperative outcomes in randomised clinical trials. | Numerous small trials have been conducted to confirm the existence of the ischaemic preconditioning (IP) mechanism in the human heart and to clarify whether it can be induced in a clinical situation. The effect on clinical end-points remains unclear. Most of the available trials reported some clinical outcomes. We performed a systematic review and meta-analysis in order to determine whether IP produces any clinical benefit in cardiac surgery. The systematic review identified 22 eligible trials containing 933 patients. All patients undergoing on-pump surgery also received cardioplegia or intermittent cross-clamp fibrillation (ICCF) with or without adjunctive cooling. IP was mainly performed after initiation of cardiopulmonary bypass, before any additional myocardial protection was initiated. Overall, IP was associated with significant reductions in ventricular arrhythmias (pooled odds ratio 0.11; 95% CI 0.04-0.29; p=0.001), inotrope requirements (pooled odds ratio 0.34; 95% CI 0.17-0.68; p=0.002) and intensive care unit stay (weighted mean difference -3h; 95% CI -4.6 to -1.5h; p=0.001). These effects persisted when the analyses were restricted to those patients receiving cardioplegia. The effect disappeared when the analyses were restricted to patients receiving ICCF. IP may provide additional myocardial protection over cardioplegia alone, but a large-scale clinical trial may be required to determine the role of IP with any certainty. |
7,375 | The hERG channel and risk of drug-acquired cardiac arrhythmia: an overview. | This review summarizes current knowledge of the cardiac rapidly activating delayed rectifier potassium current (I(Kr)), and its connection to drug-acquired QT prolongation and the associated risk of ventricular arrhythmia and fibrillation. The molecular characterization of hERG as the structural correlate of I(Kr) and the link between inherited long QT and the KCNH2 gene (hERG), have facilitated mechanistic studies of drug-acquired QT prolongation. The development of high throughput assays to evaluate drug effects on hERG has provided an avenue to determine structure activity relations (SAR) within chemical series. More than 10 years of collective data and structural considerations support the notion that hERG is an unusually promiscuous target among potassium channels, but that defining SAR within a chemical series is a viable strategy to reduce or eliminate hERG activity. Despite a critical need to minimize drug effects on hERG, one should always keep in mind that hERG is not the only structural correlate of QT prolongation, and that QT prolongation is a sub-optimal biomarker for ventricular arrhythmia and fibrillation. |
7,376 | Cardiac contractility modulation in non-responders to cardiac resynchronization therapy. | Cardiac resynchronization therapy (CRT) has become a standard therapy in cases of heart failure and asynchrony. Unfortunately, 20-30% of patients were non-responsive (NR) to CRT. In this report we used cardiac contractility modulation (CCM) as an adjunctive measure in NR patients.</AbstractText>Sixteen NR patients, mean age 65 +/- 9 years, mean ejection fraction 27.3 +/- 7.4%, and New York Heart Association (NYHA) class III (n = 9) or IV (n = 7) despite CRT plus optimized medical therapy, received an additional CCM-implantation contra-lateral to the existing CRT system (OPTIMIZER III, Impulse Dynamics, Orangeburg, NY, USA). Cardiac contractility modulation delivers non-excitatory high-energy stimulatory impulses during the absolute refractory period, thus improving contractility [left ventricular (LV) dp/dt)] by stimulating the septum with two screw-in leads and one additional atrial lead for triggering the impulses. Acute LV dp/dt changes induced by CCM stimulation were measured by 5F Millar catheters placed in the LV during the implantation procedure in 14 of 16 cases. Patients were followed prospectively. Left ventricular dp/dt increased from a mean of 568 +/- 153 to 646 +/- 147 mmHg/s (+14%, P < 0.001) in the acute intraoperative testing. We noted the following complications and events during a follow-up of an average of 147 +/- 80 days (range 68-326) after CCM: intraoperative ventricular flutter needing cardioversion (n = 1), atrial lead dislocation (n = 1), coronary sinus (CS) lead dislocation (n = 1), painful stimulation requiring repositioning of septal leads (n = 1), true defibrillator shocks (n = 3), cardiac decompensations (n = 3), atrial fibrillation (n = 4), renal failure (n = 1), and pneumonia (n = 2). NYHA class improved from 3.4 to 2.8 (P < 0.01), and the ejection fraction increased from 27.3 +/- 5 to 31.1 +/- 6 (P < 0.01). Three patients (19%) died suddenly presumably due to electromechanical dissociation after 318, 104, and 81 days. No electrical interference was observed between the CCM and CRT systems, and in particular, at no time was the CRT-implantable cardioverter-defibrillator found to be delivering inadequate shocks.</AbstractText>The CCM method is feasible and could be applied with calculated risks as a possible useful adjunct in CRT-NR when no other options are available; however, mortality and event rates are high in this very sick population.</AbstractText> |
7,377 | Esophageal cancer presenting with atrial fibrillation: a case report. | Atrial fibrillation was previously reported in patients with esophageal cancer as a complication of total esophagectomy or photodynamic therapy. Here, we propose that atrial fibrillation may also be caused by external compression of the left atrium by esophageal cancer.</AbstractText>We present a 58-year-old man who developed atrial fibrillation with rapid ventricular rate in the emergency room while being evaluated for dysphagia and weight loss. Atrial fibrillation lasted less than 12 hours and did not recur. Echocardiogram did not reveal any structural heart disease. A 10-cm, ulcerated mid-esophageal mass was seen during esophagogastroscopy. Microscopic examination showed squamous cell carcinoma. Computed tomography of the chest revealed esophageal thickening compressing the left atrium.</AbstractText>External compression of the left atrium was previously reported to provoke atrial fibrillation. Similarly, esophageal cancer may precipitate atrial fibrillation by mechanical compression of the left atrium or pulmonary veins, triggering ectopic beats in susceptible patients.</AbstractText> |
7,378 | Effect of bradyarrhythmia on the plasma levels of N-terminal pro-brain natriuretic peptide. | To investigate the effect of bradyarrhythmia on the plasma levels of NT-proBNP, patients without defined ventricular diseases were enrolled in this study: group A, 42 patients without arrhythmia; group B, 43 patients with sick sinus syndrome; group C, 22 patients with II degrees atrioventricular block (AVB); group D, 35 patients with III degrees AVB and group E, 35 patients with persistent atrial fibrillation. The plasma levels of NT-proBNP were determined and analyzed. The NT-proBNP levels were lower in group A and B than in group C, D and E (P<0.01), and in group C than in group D and E (P<0.001). Multivariate analysis revealed age and the severity of atrioventricular asynchrony were independent determinants of NT-proBNP levels (P<0.001). These results implicated that the plasma levels of NT-proBNP in patients with bradyarrhythmia increased in proportion to aggravation of atrioventricular asynchrony. |
7,379 | Reentry in an accessory atrioventricular pathway as a trigger for atrial fibrillation initiation in manifest Wolff-Parkinson-White syndrome: a matter of reflection? | Patients with an accessory pathway (AP) have an increased propensity to develop atrial fibrillation (AF), but the mechanism is unknown.</AbstractText>The purpose of this study was to identify crucial risk factors and to test the hypothesis that reflection and/or microreentry of atrial impulses propagating into the AP triggers AF.</AbstractText>Five hundred thirty-four patients successfully treated with radiofrequency ablation of AP at two university hospitals were evaluated. Patients were separated into those with concealed vs those with manifest AP in terms of their propensity to develop AF. To investigate AF triggering mechanisms, linear and branched two-dimensional models of atrium-to-ventricle propagation across a heterogeneous 1 x 6 AP using human ionic kinetics were simulated.</AbstractText>A history of AF was twice as common in patients with manifest AP vs concealed AP irrespective of AP location. AF was more likely to occur in older males and in patients with larger atria. There was no correlation between AF history and AP refractory measures. However, the electrophysiologic properties of APs seemed to fulfill the prerequisites for reflection and/or microreentry of atrially initiated impulses. In the linear AP model, repetitive atrial stimulation resulted in progressively larger delay of atrium-to-ventricle propagation across the passive segment. Eventually, sufficient time for repolarization of the atrial segment allowed for reflection of an impulse that activated the entire atrium and by wavefront-wavetail interaction with a new atrial stimulus AF reentry was initiated. Simulations using the branched model showed that microreentry at the ventricular insertion of the AP could also initiate AF via retrograde atrial activation as a result of unidirectional block at the AP-ventricle junction.</AbstractText>Propensity for AF in patients with an AP is strongly related to preexcitation, larger atria, male gender, and older age. Reflection and microreentry at the AP may be important for AF initiation in patients with manifest (preexcited) Wolff-Parkinson-White syndrome. Similar mechanisms also may trigger AF in patients without an AP.</AbstractText> |
7,380 | Prognostic value of pulse-wave tissue Doppler parameters in patients with systolic heart failure. | The aim was to study the prognostic value of left ventricular (LV) function using pulse-wave tissue Doppler imaging (TDI) in an ordinary population with heart failure (HF). One hundred fifty-six patients hospitalized for HF and LV ejection fraction < or =40% were examined using conventional echocardiography and pulse-wave TDI for the assessment of longitudinal LV function. Mitral annular systolic and early diastolic (e') velocities were recorded from a mean of 4 annular sites from the apical 2- and 4-chamber views. Noninvasive LV filling pressure was calculated from the ratio between transmitral early inflow velocity (E) and e'. All patients were followed up for 2 years, and data from the National Registry of Deaths were collected. Mean LV ejection fraction was 24.7 +/- 7.2%. TDI recordings showed a mean mitral annular systolic velocity of 5.0 +/- 1.0 cm/s and e' velocity of 6.2 +/- 1.9 cm/s. E/e' ratio was 14.1 +/- 4.8. Thirty patients (19%) had atrial fibrillation. During follow-up, 27 patients (17%) died of a cardiovascular cause. Multivariate analysis showed that only E/e' ratio and age were predictors of cardiovascular mortality. A cut-off value for E/e' ratio >13 had sensitivity of 84% and specificity of 45% to identify patients who died within 2 years of cardiac reasons. In conclusion, in the acute stage of HF, E/e' ratio is a strong independent predictor of long-term cardiovascular mortality in an ordinary population with HF and systolic dysfunction. Systolic and diastolic velocities had no independent prognostic value. |
7,381 | Preoperative and postoperative mitral valve prolapse and regurgitation in adult patients with secundum atrial septal defects. | Little attention is given to development of mitral regurgitation (MR) in adults with atrial septal defect (ASD). The aim of the study was to determine the associated factors of MR in ASD adults before surgical repair and the fate of moderate to severe MR after surgery.</AbstractText>We examined 71 consecutive patients with secundum ASD (47 +/- 16 years) who underwent surgical repair. Clinical and echocardiographic variables including size of left and right heart systems and severity of MR and tricuspid regurgitation (TR) were investigated before and early after surgery.</AbstractText>Before ASD closure, 14 patients (20%) had moderate to severe MR and 25 patients (35%) showed mitral valve (MV) prolapse. The ASD patients with moderate to severe MR showed worse cardiovascular symptoms, increased occurrence of atrial fibrillation and MV prolapse, and greater left ventricular (LV) end-diastolic volume, left atrial area, and TR severity than those with none to mild MR (all P < 0.05). Among preoperative variables, TR severity, left atrial area, LV end-diastolic volume, and MV prolapse were associated with preoperative MR severity in all the patients (all P < 0.03). Isolated ASD closure (n=46) decreased MV prolapse (P=0.008). Preoperative moderate to severe MR decreased after ASD closure with and without MV surgery (n=9 and 5, respectively; both P < 0.05).</AbstractText>Preoperative MR severity was associated with TR severity, dilated left heart chambers, and MV prolapse. MR decreased after ASD closure with and even without MV surgery.</AbstractText> |
7,382 | Prognostic importance of defibrillator shocks in patients with heart failure. | Patients with heart failure who receive an implantable cardioverter-defibrillator (ICD) for primary prevention (i.e., prevention of a first life-threatening arrhythmic event) may later receive therapeutic shocks from the ICD. Information about long-term prognosis after ICD therapy in such patients is limited.</AbstractText>Of 829 patients with heart failure who were randomly assigned to ICD therapy, we implanted the ICD in 811. ICD shocks that followed the onset of ventricular tachycardia or ventricular fibrillation were considered to be appropriate. All other ICD shocks were considered to be inappropriate.</AbstractText>Over a median follow-up period of 45.5 months, 269 patients (33.2%) received at least one ICD shock, with 128 patients receiving only appropriate shocks, 87 receiving only inappropriate shocks, and 54 receiving both types of shock. In a Cox proportional-hazards model adjusted for baseline prognostic factors, an appropriate ICD shock, as compared with no appropriate shock, was associated with a significant increase in the subsequent risk of death from all causes (hazard ratio, 5.68; 95% confidence interval [CI], 3.97 to 8.12; P<0.001). An inappropriate ICD shock, as compared with no inappropriate shock, was also associated with a significant increase in the risk of death (hazard ratio, 1.98; 95% CI, 1.29 to 3.05; P=0.002). For patients who survived longer than 24 hours after an appropriate ICD shock, the risk of death remained elevated (hazard ratio, 2.99; 95% CI, 2.04 to 4.37; P<0.001). The most common cause of death among patients who received any ICD shock was progressive heart failure.</AbstractText>Among patients with heart failure in whom an ICD is implanted for primary prevention, those who receive shocks for any arrhythmia have a substantially higher risk of death than similar patients who do not receive such shocks.</AbstractText>2008 Massachusetts Medical Society</CopyrightInformation> |
7,383 | Predictive factors of sustained sinus rhythm and recurrent atrial fibrillation after a radiofrequency modified Maze procedure. | Preoperative atrial fibrillation (AF) in patients scheduled for elective open-heart surgery is a well-known phenomenon. The cut and sew Maze procedure or variant Maze procedures abolish AF in 45-95% of patients during short- to intermediate-term follow-up. We determined preoperative and postoperative factors predictive of sustained sinus rhythm (SR) and recurrent AF in an elderly cohort of patients with structural heart disease who underwent cardiac surgery.</AbstractText>From November 1995 to November 2003, 285 patients with structural heart disease and permanent AF were scheduled for elective cardiac surgery. All patients underwent a radiofrequency (RF) modified Maze procedure as an adjunct to the open-heart operation. Patients were followed in the outpatient clinic or follow-up data were obtained from attending doctors. Patients are being followed in an ongoing registry; however for the patients who are the subject of this paper follow-up ended November 2006. Preoperative factors predicting recurrent AF postoperatively were assessed, as were factors associated with sustained SR.</AbstractText>Two hundred and eighty-five patients (mean age 68.0+/-9.6 years) underwent a total of 655 open-heart procedures and concomitant RF Maze surgery. In-hospital mortality was 4.6% (13 patients). Mean and median duration of AF were 60.9+/-68.7 months and 26 months (range 6-396), respectively. Median follow-up was 36.5 months (range 27-114 months). Sustained SR, including atrial rhythm or an atrial-based paced rhythm was present in 59% of patients at 1 year, in 54.4% at 3 years, in 53.4% at 5 years and in 57.1% of patients at the latest follow-up. Stroke was reported in six patients (2.1%). Factors predictive of postoperative AF recurrence were duration of permanent AF, preoperative atrial fibrillation wave and preoperative left atrial (LA) size. Postoperative angiotensin converting enzyme (ACE) inhibitor therapy was associated with SR during follow-up. LA size decreased during follow-up in patients with sustained SR, whereas LA size increased in case of recurrent AF.</AbstractText>In this group of elderly patients with permanent AF in the setting of structural heart disease who underwent cardiac surgery and a RF Maze procedure as a concomitant procedure, the duration of AF, preoperative atrial fibrillation wave and preoperative LA size were predictive of recurrent AF, whereas left ventricular ejection fraction, left ventricular diameters and invasive hemodynamic parameters were not. Postoperative ACE inhibitor therapy was associated with sustained SR. Furthermore, sustained SR after RF Maze surgery was associated with decreased LA dimensions.</AbstractText> |
7,384 | [Arrhythmias during pregnancy]. | Cardiovascular emergencies are rare during pregnancy with an incidence of 0,2-4,0%. Emergencies include arrhythmias, acute coronary syndrome, peripartum cardiomyopathy and hypertensive disorders. Electrical DC-cardioversion with 50-100 Joules is indicated in the acute treatment of arrhythmias in all patients in an unstable hemodynamic state. If 100 J fails higher energies (up to 360 J) will be necessary. In stable supraventricular tachycardia intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are frequently present during pregnancy and benign in most patients. However, life-threatening ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlt], ventricular fibrillation [VF]) were observed less frequently. Electrical DC-cardioversion is necessary in all pregnant women who are in a hemodynamically unstable state and have a life-threatening ventricular tachyarrhythmias. In hemodynamically stable pregnant women the initial therapy with ajmaline, procainamide or lidocaine is indicated. Implantation of a cardioverter-defibrillator is indicated in patients with syncope caused by VT, VF, VFlt or aborted sudden death. |
7,385 | Experimental study of a novel method of cardiopulmonary resuscitation using a combination of percutaneous cardiopulmonary support and liposome-encapsulated hemoglobin (TRM645). | Percutaneous cardiopulmonary support (PCPS) has been applied for cardiopulmonary arrest (CPA). We have developed a novel method of cardiopulmonary resuscitation using PCPS combined with liposome-encapsulated hemoglobin (TRM645) to improve oxygen delivery to vital organs. Ventricular fibrillation was electrically induced to an adult goat for 10 min. Next, PCPS (30 ml/kg/min, V/Q: 1) was performed for 20 min. Then, external defibrillation was attempted and observed for 120 min. The TRM group (n5) was filled with 300 mL of TRM645 for the PCPS circuit. The control group (n5) was filled with the same volume of saline. The delivery of oxygen (DO2) and oxygen consumption (VO2) decreased markedly by PCPS after CPA, compared to the preoperative values. DO2 was kept at a constant level during PCPS in both groups, but VO2 slowly decreased at 5, 10, and 15 min of PCPS in the control groups, demonstrating that systemic oxygen metabolism decreased with time. In contrast, the decreases in VO2 were small in the TRM group at 5, 10, and 15 min of PCPS, demonstrating that TRM645 continuously maintained systemic oxygen consumption even at a low flow rate. AST and LDH in the TRM group were lower than the control. There were significant differences at 120 min after the restoration of spontaneous circulation (p<0.05). |
7,386 | Indeterminacy of spatiotemporal cardiac alternans. | Cardiac alternans, a beat-to-beat alternation in action potential duration (at the cellular level) or in electrocardiogram morphology (at the whole heart level), is a marker of ventricular fibrillation, a fatal heart rhythm that kills hundreds of thousands of people in the United States each year. Investigating cardiac alternans may lead to a better understanding of the mechanisms of cardiac arrhythmias and eventually better algorithms for the prediction and prevention of such dreadful diseases. In paced cardiac tissue, alternans develops under increasingly shorter pacing period. Existing experimental and theoretical studies adopt the assumption that alternans in homogeneous cardiac tissue is exclusively determined by the pacing period. In contrast, we find that, when calcium-driven alternans develops in cardiac fibers, it may take different spatiotemporal patterns depending on the pacing history. Because there coexist multiple alternans solutions for a given pacing period, the alternans pattern on a fiber becomes unpredictable. Using numerical simulation and theoretical analysis, we show that the coexistence of multiple alternans patterns is induced by the interaction between electrotonic coupling and an instability in calcium cycling. |
7,387 | Acute effects of angiotensin II receptor blocker on ventricular repolarization alternans in chronic heart failure. | Repolarization alternans, which can be detected clinically as microvolt-level T-wave alternans (TWA), is considered an important mechanism underlying the initiation of ventricular tachycardia/ventricular fibrillation (VT/VF) linked to sudden cardiac death (SCD). Recently, the rennin-angiotensin system (RAS) inhibitors have been suggested to have potential benefits in reducing SCD as well as heart failure death with chronic heart failure (CHF). In this study, we tested the acute effects of an angiotensin II receptor blocker (ARB), valsartan, on the development of TWA and the heart rate at which TWA appeared (onset heart rate; OHR). Fifty consecutive patients with CHF underwent TWA measurement. Patients with positive TWA were administered valsartan (80 mg/day) orally for 3 days. Alternans voltage in the vector magnitude lead (Valt) and the OHR were compared before and after the drug exposure. TWA was positive in 19 patients (38%), negative in 16 (32%), and indeterminate in 15 (30%). Nineteen patients with positive TWA received valsartan. However, 3 patients were withdrawn due to adverse drug reactions. In all the remaining 16 patients, markedly reduced Valt (6.1 +/- 3.8 microV to 2.5 +/- 1.9 microV; P = 0.002) and increased OHR (94 +/- 9 beats/min to 102 +/- 9 beats/min; p = 0.002) were observed. In particular, 3 patients became TWA negative. These results suggest that the RAS inhibitors prevent SCD by the improvement of repolarization abnormality. |
7,388 | Risk stratification of patients with prior myocardial infarction and advanced left ventricular dysfunction by gated myocardial perfusion SPECT imaging. | The Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) has shown that the prophylactic implantable cardiac defibrillator improves the survival rate of patients with prior myocardial infarction and advanced left ventricular (LV) dysfunction. However, a more accurate noninvasive predictor should be found to identify subgroups at high risk, one that would allow implantable cardiac defibrillator therapy to be directed specifically to the patients who would benefit most.</AbstractText>To elucidate whether technetium 99m tetrofosmin electrocardiogram-gated single photon emission computed tomography (SPECT) imaging at rest can determine the risk of arrhythmic death, 106 patients who met the MADIT-II criteria (LV ejection fraction <or=0.3, myocardial infarction >1 month earlier, and no sustained ventricular tachyarrhythmia) were recruited from a pool of 4628 consecutive patients who had undergone resting Tc-99m tetrofosmin SPECT imaging. By use of the endpoints of lethal arrhythmic events, which included documentation of sustained ventricular tachycardia, ventricular fibrillation, or diagnosis of sudden cardiac death, we performed follow-up for a mean of 30 months. Lethal arrhythmic events occurred in 14 patients. Patients with lethal arrhythmic events had a lower LV ejection fraction, greater LV end-systolic and end-diastolic volume indices, and a greater perfusion defect volume than the remaining patients. By receiver operating characteristic curve analysis, myocardial defect volume was the strongest predictor for the development of lethal arrhythmic events.</AbstractText>Our results confirm that perfusion defect volume by Tc-99m tetrofosmin scintigraphy is the most pivotal predictor of the future occurrence of lethal arrhythmic events and of sudden cardiac death. Tc-99m tetrofosmin SPECT images may assist in identifying subsets of patients with a greater likelihood of arrhythmic death among patients with LV dysfunction.</AbstractText> |
7,389 | Extended cervical mediastinoscopy in the staging of bronchogenic carcinoma of the left lung. | To evaluate the technical feasibility and the sensitivity, specificity and accuracy of extended cervical mediastinoscopy (ECM) in the staging of bronchogenic carcinoma (BC) of the left lung.</AbstractText>From 1998 to 2003, 89 patients underwent routine ECM for staging of BC of the left lung. In 2004, positron emission tomography (PET) was included in our staging protocol and ECM was reserved for those with positive mediastinal or hilar PET images, large lymph nodes on computed tomography (CT) scan or central tumours. From 2004 to 2007 we performed selective ECM in 67 patients. ECM was considered positive when metastatic nodes or tumour involvement directly in the subaortic or para-aortic regions was confirmed pathologically. One hundred and forty-three patients with negative ECM underwent subsequent thoracotomy for tumour resection and systematic nodal dissection. Pathological findings were reviewed and staging values were calculated.</AbstractText>One hundred and fifty-six patients underwent ECM (89 routine and 67 selective). In 13, ECM was positive and thoracotomy was contraindicated. The rest of the patients were operated. We performed 88 lobectomies, 34 pneumonectomies, 6 wedge resections, 13 exploratory thoracotomies and 2 parasternal mediastinotomies. Lymphadenectomy specimens showed tumour involvement of subaortic lymph nodes in 8 patients. Complication rate was 2%: two cases of mediastinitis, one ventricular fibrillation, and one superficial surgical wound infection. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of routine/selective ECM were: 0.45/0.75, 1/1, 1/1, 0.94/0.95, 0.94/0.95, respectively.</AbstractText>ECM is a feasible staging technique that allows ruling out subaortic and para-aortic nodal disease with high negative predictive value, accuracy and sensitivity. Its indication based on the CT and PET findings seems more advisable that its routine use to stage bronchogenic carcinoma of the left lung.</AbstractText> |
7,390 | Effects of sympathetic nerve stimulation on ischemia-induced ventricular arrhythmias by modulating connexin43 in rats. | Increased cardiac sympathetic nerve activity is thought to contribute to ventricular tachyarrhythmias during acute myocardial ischemia (MI). However, the mechanism is not completely understood. This study investigated the effects of sympathetic nerve stimulation (SNS) on ventricular tachyarrhythmias and connexin43 (Cx43) during acute MI in rats.</AbstractText>Ninety five male Wistar rats were randomly assigned into four groups receiving the following treatments: myocardial ischemia with sympathetic nerve stimulation (MI-SNS, n=25), sham-operation treated with sham stimulation (SO, n=20), myocardial ischemia with sham stimulation (MI, n=25), myocardial ischemia pretreated with sympathetic nerve stimulation (pSNS-MI, n=25).</AbstractText>During the 30-min ischemia, the incidence of ventricular tachyarrhythmias, i.e., ventricular tachycardia or ventricular fibrillation (VT/VF) was increased in the MI-SNS group and decreased in the pSNS-MI group compared to that in the MI group (p<0.05 for both). The total amount of Cx43 protein was significantly decreased in the MI-SNS group but not in the MI group and the pSNS-MI group. The amount of phosphorylated Cx43 in the MI-SNS group was significantly lower compared to that in the SO group and the MI group (p<0.05). However, the amount of phosphorylated Cx43 was significantly increased in the pSNS-MI group compared to that in the MI group and the MI-SNS group (p<0.05).</AbstractText>SNS promoted the degradation of Cx43 protein, especially the phosphorylated Cx43 protein, whereas pSNS inhibited the ischemia-induced loss of phosphorylated Cx43 during acute MI. These changes may be related to the pro- or anti-arrhythmic effect of SNS or pSNS during acute MI.</AbstractText> |
7,391 | Dronedarone for the control of ventricular rate in permanent atrial fibrillation: the Efficacy and safety of dRonedArone for the cOntrol of ventricular rate during atrial fibrillation (ERATO) study. | Dronedarone is a new multichannel blocker for atrial fibrillation (AF) previously demonstrated to have both rhythm and rate control properties in paroxysmal and persistent AF. The Efficacy and safety of dRonedArone for The cOntrol of ventricular rate during atrial fibrillation (ERATO) trial assessed the efficacy of dronedarone in the control of ventricular rate in patients with permanent AF, when added to standard therapy.</AbstractText>In this randomized, double-blind, multinational trial, dronedarone, 400 mg twice a day (n = 85), or matching placebo (n = 89) was administered for 6 months to adult patients with permanent AF, in addition to standard therapy. The primary end point was the change in mean ventricular rate between baseline and day 14, as assessed by 24-hour Holter. Ventricular rate was also assessed during submaximal and maximal exercise.</AbstractText>Dronedarone significantly decreased mean 24-hour ventricular rate. Compared with placebo, the mean treatment effect at day 14 was a reduction of 11.7 beats per minute (beat/min; P < .0001). Comparable reductions were sustained throughout the 6-month trial. During maximal exercise and compared to placebo, there was a mean reduction of 24.5 beat/min (P < .0001), without any reduction in exercise tolerance as measured by maximal exercise duration. The effects of dronedarone were additive to those of other rate-control agents, including beta-blockers, calcium antagonists, and digoxin. Dronedarone was well tolerated, with no organ toxicities or proarrhythmia.</AbstractText>In addition to its reported rhythm-targeting and rate-targeting therapeutic actions in paroxysmal and persistent AF, dronedarone improves ventricular rate control in patients with permanent AF. Dronedarone was well tolerated with no evidence of organ toxicities or proarrhythmias in this short-term study.</AbstractText> |
7,392 | Atrial fibrillation in recipients of cardiac resynchronization therapy device: 1-year results of the randomized MASCOT trial. | Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP).</AbstractText>The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year.</AbstractText>Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF.</AbstractText>In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.</AbstractText> |
7,393 | Predictors of improved quality of life 1 year after pacemaker implantation. | Patient's health-related quality of life (HRQoL) of pacemaker (PM) patients has increasingly become an important issue of health care evaluation. Currently, knowledge of pacing performance and technology is more or less outlined. However, determinants of poor or good HRQoL of paced patients require further elucidation.</AbstractText>The purpose of this study is to determine the HRQoL 1 year after PM implantation and predictors of differences in HRQoL between pre- and post-PM implantation.</AbstractText>We quantified the mean differences between HRQoL before implantation (baseline) and 1 year later, assessed with the generic Medical Outcomes Survey 36-Item Short-Form Survey and EuroQol (EQ5D), and the PM patient-specific AQUAREL (Assessment of QUality of life And RElated events) questionnaires, in 501 consecutively included patients in the Dutch multicenter longitudinal FOLLOWPACE cohort study. Multivariable linear regression modeling was then performed to determine predictive factors of the HRQoL 1 year after implantation.</AbstractText>The HRQoL of the patients increased markedly in the first year after implantation. Seventy percent of the patients considered their health improved, whereas 11% experienced a complete recovery in HRQoL. The most important predictors for improved HRQoL after 1 year were HRQoL at baseline, age, presence of cardiac comorbidities, and atrial fibrillation with slow ventricular response as indication for chronic pacing.</AbstractText>In most patients receiving a PM, HRQoL increased in the first year after PM implantation. Knowledge of the predictors of this increase may aid physicians to timely differentiate between patients who most likely will benefit most from PM implantation in terms of HRQoL.</AbstractText> |
7,394 | The MINERVA study design and rationale: a controlled randomized trial to assess the clinical benefit of minimizing ventricular pacing in pacemaker patients with atrial tachyarrhythmias. | Dual-chamber (DDD) pacing has generally been regarded as "physiologic pacing" and therefore expected to be superior to ventricular pacing. Major randomized trials have so far failed to demonstrate significant reductions in the incidences of mortality, stroke, and heart failure. It has been shown that unnecessary ventricular pacing in patients with sinus node dysfunction or only intermittent atrioventricular block is associated with ventricular desynchronization and increased risk of atrial tachyarrhythmias (ATA).</AbstractText>The MINimizE Right Ventricular pacing to prevent Atrial fibrillation and heart failure (MINERVA) study is a prospective, multi-center, randomized, international, single-blind, controlled trial designed to determine whether physiologic pacing through the managed ventricular pacing (MVP) algorithm combined with preventive atrial pacing (PAP) and atrial antitachycardia pacing (ATP) is superior to standard DDD pacing in terms of 2-year reduction in death, permanent ATA, and cardiovascular hospitalizations. Patients with standard class I or II indications for permanent DDD pacing and history of ATA will receive a Medtronic EnRhythm implantable pacemaker (Medtronic, Minneapolis, MN). After a 1-month run-in period, patients will be randomized in a 1:1:1 manner to the DDD (control group, all OFF), the DDDRP (MVP + PAP + ATP ON), and the MVP group (only MVP ON). Up to 1,300 patients will be included in approximately 70 centers in Europe, the Middle East, and Asia.</AbstractText>The MINERVA study will make an important contribution to the management of patients with paroxysmal ATA and accepted indications for dual-chamber pacemaker implantation by determining whether physiologic pacing combined with PAP and ATP is superior to standard DDD pacing in terms of reduction of mortality, incidence of permanent ATA, and cardiovascular hospitalizations.</AbstractText> |
7,395 | Prognostic value of left ventricular myocardial performance index in patients undergoing coronary artery bypass graft surgery. | Left ventricular myocardial performance index is a Doppler-derived parameter of nongeometrical ventricular function that measures both systolic and diastolic function of the left ventricle. The objective of this study was to compare prognostic value of left ventricular myocardial performance index with global left ventricle function in patients undergoing coronary artery bypass graft surgery.</AbstractText>One hundred consecutive patients who underwent coronary artery bypass graft surgery for coronary artery disease were studied from March 2004 through September 2006. Recovery of global left ventricle function and left ventricular myocardial performance index were measured serially by Doppler echocardiography after coronary artery bypass graft surgery. The patients were under supervision for four months after discharging from hospital. We studied the incidence of atrial fibrillation, postoperative myocardial infarction, pericardial and pleural effusion, infection, and also ventilation time and intensive care unit stay. For analysis of the events, we divided the patients into two groups. Group A was considered with left ventricle ejection fraction of <40% and group B had a left ventricle ejection fraction of >40%.</AbstractText>Global left ventricle ejection fraction and left ventricular myocardial performance index were not related to pericardial effusion, pleural effusion, and postoperative infection. In group A, left ventricular myocardial performance index had more prognostic value for prediction of incidence of atrial fibrillation rhythm and postoperative myocardial infarction than the global left ventricle ejection fraction. But global left ventricle ejection fraction had more prognostic value for ventilation time and intensive care unit stay in comparison with left ventricular myocardial performance index. These associations were not seen in group B.</AbstractText>The prognostic effect of left ventricular myocardial performance index was no more than global left ventricle ejection fraction in early and late complications of coronary artery bypass graft surgery but only affirm global left ventricle ejection fraction in some situations.</AbstractText> |
7,396 | Post-operative atrial fibrillation management by selective epicardial vagal fat pad stimulation. | Post-operative atrial fibrillation (POAF) is a common complication after cardiac surgery and often leads to poorly tolerated fast ventricular rates. Negative dromotropic drugs are not always effective and may not be well tolerated in heart failure patients. Aim of this study is to verify if high-frequency stimulation of the right inferior fat pad (RIFPS) allows an effective decrease in ventricular rate (VR) during POAF.</AbstractText>We enrolled 32 consecutive patients submitted to bypass; during surgery, a temporary heart wire was implanted in a site where RIFPS evoked a functional AV block. During POAF, RIFPS was delivered from the heart wire to decrease VR.</AbstractText>Intra-operative RIFPS evoked complete AV block in 29 patients (91%). Fourteen patients (44%) developed POAF (mean VR 127 +/- 12 bpm). In these patients, RIFPS achieved a 25% reduction of VR and complete AV block with 6.0 +/- 1.9 and 7.5 +/- 1.8 V (duration 0.2 ms, frequency 50 Hz), respectively.</AbstractText>Epicardial RIFPS represents an effective and feasible technique to decrease VR during POAF.</AbstractText> |
7,397 | The future of implantable defibrillator and cardiac resynchronization therapy trials. | Implantable cardioverter defibrillator (ICD) trials were initially limited to survivors of sudden death. The focus of defibrillator trials in the last decade has been in prophylactic implantation of the device in high risk populations for the prevention of sudden cardiac death. It is the contention in this review that the new focus for implantable defibrillator trials in 2008 and beyond will be on more selective and focused use of this therapy. This could be achieved by selecting ICD patients based on their pathophysiologic and genetic risk. Increasing effort will also be placed on using the device for prevention of spontaneous malignant ventricular tachyarrhythmias and the index clinical sudden death event. Finally, implantable defibrillators will be used in combination in a "hybrid" therapy approach. ICDs will be increasingly combined either with ventricular tachycardia ablation or ventricular fibrillation ablation using catheter techniques. With the addition of cardiac resynchronization therapy in these devices, new clinical trials that use cardiac resynchronization therapy as an early intervention in specific high risk heart failure populations and refinement of the CRT technique to improved optimal results are in progress. Finally, combining ICD devices and regenerative medicine approaches to myocardial replacement therapy are being explored. |
7,398 | Dipyridamole therapy improves long-term survival after complete revascularization in patients with impaired cardiac function: a propensity analysis. | Although dipyridamole is no longer used as a mainstream medication for coronary artery disease because of the coronary steal phenomenon, recent studies have shown that the elevation of serum adenosine levels caused by dipyridamole improves cardiac function in heart failure patients. In the present study it was investigated whether use of dipyridamole at the time of complete revascularization affects long-term mortality in patients with impaired left ventricular (LV) function.</AbstractText>The 1,836 consecutive patients who underwent complete revascularization between 1984 and 1992 were assessed; 254 patients with impaired LV function (ejection fraction < 50%) were enrolled. Cox proportional hazards regression adjusted for baseline covariates and the propensity score were used to compare the risks for mortality between patients who did and did not take dipyridamole. The mean follow-up period was 12 years; 178 patients (70.1%) took dipyridamole and there were 66 (37.1%) all-cause and 22 (12.4%) cardiac deaths in that group. In the multivariate analysis, the dipyridamole group had a lower risk for both all-cause (hazard ratio (HR) 0.54; p = 0.005) and cardiac mortality (HR 0.42; p = 0.010).</AbstractText>The use of dipyridamole reduced both all-cause and cardiac mortality in patients with impaired LV function.</AbstractText> |
7,399 | Off-pump versus on-pump--intermittent aortic cross clamping--myocardial revascularisation: single center expirience. | The aim of this randomised, prospective study was to evaluate hospital mortality and morbidity after myocardial revascularisation, comparing on-pump coronary artery bypass graft (CABG) myocardial revascularisation versus off-pump coronary artery bypass graft (OPCAB) myocardial revascularisation in population with multivessels coronary artery disease. Sixty patients with multivessels coronary artery diseases were scheduled to undergo coronary artery bypass grafting from January 15, 2006 to June 30, 2007 in our institution. Patients were randomized to off-pump or on-pump surgery with intermittent cross-clamping of aorta and ventricular fibrillation, using the envelope method with random numbers. In the results only difference we did find postoperatively was in Creatine Kinase-MB (CK-MB) release, the amount of bleeding and intensive care unit (ICU) stay (p<0.05). There was no diference between the two groups of patients regarding incidence of main morbidity and hospital moratlity. In summary, we didn't find no superiority in any of the two techniques regarding on hospital mortality and morbidity. |
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