Related Experiment Videos
Causes of death in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial
Insights
The implantable cardioverter-defibrillator (ICD) significantly reduces arrhythmic deaths compared to antiarrhythmic drugs (AADs) in patients with life-threatening ventricular arrhythmias. While ICDs improve survival, understanding non-arrhythmic death causes remains crucial.
Area of Science:
- Cardiology
- Clinical Trials
- Electrophysiology
Background:
- Life-threatening ventricular arrhythmias necessitate treatment with antiarrhythmic drugs (AADs) or implantable cardioverter-defibrillators (ICDs).
- The Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial compared the efficacy of ICDs versus AADs.
- Assessing causes of death in the AVID Trial elucidates the mechanisms behind improved survival with ICDs.
Purpose of the Study:
- To analyze the causes of death in patients participating in the AVID Trial.
- To compare the effectiveness of ICDs versus AADs in preventing specific types of mortality.
- To understand the impact of ICDs and AADs on arrhythmic versus non-arrhythmic death.
Main Methods:
- Analysis of 202 deaths among 1,016 patients enrolled in the AVID Trial.
- Independent review of death classifications by the Principal Investigator and an unblinded Events Committee.
- Categorization of deaths into cardiac (arrhythmic/non-arrhythmic) and noncardiac causes.
Main Results:
- Fewer deaths occurred in the ICD group (n=80) compared to the AAD group (n=122) (p < 0.001).
- ICDs significantly reduced arrhythmic cardiac deaths (ICD=24 vs. AAD=55, p < 0.001).
- Non-arrhythmic cardiac deaths were similar between groups (39 each), while AAD patients had more noncardiac deaths (28 vs. 17).
Conclusions:
- ICDs are more effective than AADs in reducing arrhythmic cardiac death, with non-arrhythmic cardiac death remaining unchanged.
- Despite ICD use, a significant proportion (38%) of cardiac deaths were still classified as arrhythmic.
- The ICD demonstrates superiority over AADs in prolonging survival for patients experiencing life-threatening arrhythmias.
Objectives:
This study analyzed the causes of death in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial.
Background:
Both implantable cardioverter-defibrillators (ICDs) and antiarrhythmic drugs (AADs) are used as mainstays of treatment for life-threatening ventricular arrhythmias in patients who have survived either ventricular fibrillation or sustained ventricular tachycardia with hemodynamic compromise and serious symptoms. The AVID Trial compared the effectiveness of these two therapies. Survival was better with the ICD. Assessment of the cause of death should help to determine the mechanism of improvement in survival with the ICD.
Methods:
Of 1,016 patients enrolled in the AVID Trial, 202 patients died. The mode of death was determined by the unblinded Principal Investigator and independently by an Events Committee, which reviewed materials meticulously blinded with respect to treatment. Deaths were classified as cardiac or noncardiac. Cardiac deaths were further classified as arrhythmic or nonarrhythmic, and causes of noncardiac death were identified.
Results:
Deaths were more frequent in patients treated with an AAD (n = 122), compared with patients treated with the ICD (n = 80), unadjusted p < 0.001, p = 0.012 adjusted for sequential monitoring. In AVID, 157 deaths were cardiac, and 79 were arrhythmic. The major effect of the ICD was to prevent arrhythmic death (AAD = 55, ICD = 24, nominal unadjusted p < 0.001). Nonarrhythmic cardiac deaths were equal (AAD = 39, ICD = 39). Patients treated with an AAD had a slightly greater incidence of noncardiac deaths (28 vs. 17, p = 0.053), primarily due to pulmonary and renal causes.
Conclusions:
The ICD is more effective than an AAD in reducing arrhythmic cardiac death, while nonarrhythmic cardiac death is unchanged. Of note, apparent arrhythmic death still seems to constitute 38% of all cardiac deaths despite treatment with an ICD. However, the ICD remains superior to an AAD in prolonging survival after life-threatening arrhythmias.