Randomized comparison of antiarrhythmic drug therapy with implantable defibrillators in patients resuscitated from cardiac arrest - The Cardiac Arrest Study Hamburg (CASH)

Background-We conducted a prospective, multicenter, randomized comparison o f implantable cardioverter-defibrillator (ICD) versus antiarrhythmic drug t herapy in survivors of cardiac arrest secondary to documented ventricular a rrhythmias. Methods and Results-From 1987, eligible patients were randomized to an ICD, amiodarone, propafenone, or metoprolol (ICD versus antiarrhythmic agents r andomization ratio 1:3). Assignment to propafenone was discontinued in Marc h 1992, after an interim analysis conducted in 58 patients showed a 61% hig her all-cause mortality rate than in 61 ICD patients during a follow-up of 11.3 months. The study continued to recruit 288 patients in the remaining 3 study groups; of these, 99 were assigned to ICDs, 92 to amiodarone, and 97 to metoprolol. The primary end point was all-cause mortality. The study wa s terminated in March 1998, when all patients had concluded a minimum 2-yea r follow-up. Over a mean follow-up of 57+/-34 months, the crude death rates were 36.4% (95% CI 26.9% to 46.6%) in the ICD and 44.4% (95% CI 37.2% to 5 1.8%) in the amiodarone/metoprolol arm. Overall survival was higher, though not significantly, in patients assigned to ICD than in those assigned to d rug therapy (I-sided P=0.081, hazard ratio 0.766, [97.5% CI upper bound 1.1 12]). In ICD patients, the percent reductions in all-cause mortality were 4 1.9%, 39.3%, 28.4%, 27.7%, 22.8%, 11.4%, 9.1%, 10.6%, and 24.7% at years 1 to 9 of follow-up. Conclusions-During long-term follow-up of cardiac arrest survivors, therapy with an ICD is associated with a 23% (nonsignificant) reduction of all-cau se mortality rates when compared with treatment with amiodarone/metoprolol. The benefit of ICD therapy is more evident during the first 5 years after the index event.