Comparison of dilated cardiomyopathy and coronary artery disease in patients with life-threatening ventricular arrhythmias: Differences in presentation and outcome in the AVID registry.

BACKGROUND: The etiology of structural heart disease in patients with life-threatening arrhythmias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) may define clinical characteristics at presentation, may require that different therapies be administered, and may cause different mortality outcomes. METHODS: In the Antiarrhythmics Versus Implantable Defibrillators (AVID) registry, baseline clinical characteristics, treatments instituted, and ultimate mortality outcomes from the National Death Index were obtained on 3117 patients seen at participating institutions with VT/VF, irrespective of participation in the randomized trial. By use of these data, 2268 patients with coronary artery disease (CAD) were compared with 334 patients with dilated nonischemic cardiomyopathy (DCM). RESULTS: The CAD group was 7 years older and had a higher percentage of males. DCM patients were more likely to be African American, have severely compromised left ventricular function (52% vs 39%), and have a history of congestive heart failure symptoms (62% vs 44%). Patients with CAD were more likely to be treated with b-blockers and calcium channel blockers and less likely to be treated with angiotensin-converting enzyme inhibitors. Patients with DCM were more likely to be treated with diuretics, warfarin, and an implantable cardioverter defibrillator for VT/VF (54% vs 48% for CAD); the use of other antiarrhythmic therapies did not differ between the 2 groups. Two-year survival was not significantly different between the groups (76.6% [95% CI 74.6%-78.7%] vs 78.2% [95% CI 73.6%-82.9%]). CONCLUSIONS: In AVID registry patients with VT/VF, demographic and clinical characteristics were different between patients with CAD and those with DCM. Despite these differences, overall survival was similar in these 2 groups.

Electrical storm presages nonsudden death: the antiarrhythmics versus implantable defibrillators (AVID) trial.

BACKGROUND: Electrical storm, multiple temporally related episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF), is a frequent problem among recipients of implantable cardioverter defibrillators (ICDs). However, insufficient data exist regarding its prognostic significance. METHODS AND RESULTS: This analysis includes 457 patients who received an ICD in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial and who were followed for 31 +/- 13 months. Electrical storm was defined as > or = 3 separate episodes of VT/VF within 24 hours. Characteristics and survival of patients surviving electrical storm (n = 90), those with VT/VF unrelated to electrical storm (n = 184), and the remaining patients (n = 183) were compared. The 3 groups differed in terms of ejection fraction, index arrhythmia, revascularization status, and baseline medication use. Survival was evaluated using time-dependent Cox modeling. Electrical storm occurred 9.2 +/- 11.5 months after ICD implantation, and most episodes (86%) were due to VT. Electrical storm was a significant risk factor for subsequent death, independent of ejection fraction and other prognostic variables (relative risk [RR], 2.4; 95% confidence interval [CI], 1.3 to 4.2; P = 0.003), but VT/VF unrelated to electrical storm was not (RR, 1.0; 95% CI, 0.6 to 1.7; P = 0.9). The risk of death was greatest 3 months after electrical storm (RR, 5.4; 95% Cl, 2.4 to 12.3; P = 0.0001) and diminished beyond this time (RR, 1.9; 95% CI, 1.0 to 3.6; P=0.04). CONCLUSIONS: Electrical storm is an important, independent marker for subsequent death among ICD recipients, particularly in the first 3 months after its occurrence. However, the development of VT/VF unrelated to electrical storm does not seem to be associated with an increased risk of subsequent death.

"Stable" ventricular tachycardia is not a benign rhythm : insights from the antiarrhythmics versus implantable defibrillators (AVID) registry.

BACKGROUND: Sustained ventricular tachycardia (VT) can be unstable, can be associated with serious symptoms, or can be stable and relatively free of symptoms. Patients with unstable VT are at high risk for sudden death and are best treated with an implantable defibrillator. The prognosis of patients with stable VT is controversial, and it is unknown whether implantable cardioverter-defibrillator therapy is beneficial. METHODS AND RESULTS: Screening for the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial identified patients with both stable and unstable VT. Both groups were included in a registry, and their clinical characteristics and discharge treatments were recorded. Mortality data were obtained through the National Death Index. The mortality in 440 patients with stable VT tended to be greater than that observed in 1029 patients presenting with unstable VT (33.6% versus 27.6% at 3 years; relative risk [RR]=1.22; P:=0.07). After adjustment for baseline and treatment differences, the RR was little changed (RR=1.25, P:=0.06). CONCLUSIONS: Sustained VT without serious symptoms or hemodynamic compromise is associated with a high mortality rate and may be a marker for a substrate capable of producing a more malignant arrhythmia. Implantable cardioverter-defibrillator therapy may be indicated in patients presenting with stable VT.

Lead- and device-related complications in the antiarrhythmics versus implantable defibrillators trial.

BACKGROUND: Implantation of transvenous implantable cardioverter defibrillators (ICDs) by use of a nonthoracotomy approach has become routine therapy for survivors of life-threatening tachyarrhythmias. The purpose of this study was to identify and prospectively characterize the frequency of lead- and ICD-related complications from the Antiarrhythmics versus Implantable Defibrillators (AVID) Trial. METHODS AND RESULTS: Between June 1, 1993, and April 7, 1997, 539 patients received nonthoracotomy ICDs either as initial treatment assignment (477) or as crossover from medical management (62). A total of 62 first complications occurred. The subclavian route of insertion resulted in more complications than the cephalic vein route, 46 of 339 (14%) versus 6 of 135 (4%), P = .005, as did the abdominal versus pectoral generator site, 31 of 238 (13%) versus 17 of 291 (6%), P<.02. Most dislodgements and system infections tended to occur in the 3 months after implantation, whereas lead fractures continued to occur throughout follow-up. Failure to use perioperative antibiotics was a predictor of system infection (P = .001). CONCLUSIONS: These data suggest that cephalic vein access and pectoral generator site may result in fewer complications. The continued occurrence of lead fractures and the need for premature system revision supports the practice of close routine ICD system surveillance.