Canadian implantable defibrillator study (CIDS) : a randomized trial of the implantable cardioverter defibrillator...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Patients surviving ventricular fibrillation (VF) or sustained ventricular tachycardia (VT) face a high risk of mortality from arrhythmia recurrence.
• The efficacy of implantable cardioverter defibrillators (ICDs) in prolonging survival compared to amiodarone in these patients remains unclear.

Purpose of the Study:

• To compare the effectiveness of ICD therapy versus amiodarone in reducing all-cause and arrhythmic mortality in patients who survived VF or VT.
• To evaluate the long-term outcomes of ICD implantation versus medical management with amiodarone.

Main Methods:

• A randomized trial involving 659 patients who had resuscitated from VF or VT or experienced unmonitored syncope.
• Patients were assigned to either ICD therapy or amiodarone treatment.
• Primary outcome was all-cause mortality; secondary outcome was arrhythmic death, followed for 5 years.

Main Results:

• The ICD group showed a nonsignificant 19.7% relative risk reduction in all-cause mortality (8.3% per year vs. 10.2% per year).
• A nonsignificant 32.8% relative risk reduction in arrhythmic death was observed with ICDs (3.0% per year vs. 4.5% per year).
• At 5 years, amiodarone was still used by 85.4% of the amiodarone group, while 28.1% of ICD patients also received amiodarone.

Conclusions:

• ICD therapy demonstrated a trend towards reducing both all-cause and arrhythmic mortality compared to amiodarone.
• The observed reductions in mortality did not reach statistical significance, suggesting further research may be needed.
• A significant crossover between treatment groups was noted, with amiodarone patients receiving ICDs and vice versa.