Analysis of Implantable Cardioverter Defibrillator Therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial

Abstract

Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided.

2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing

“…The initial generations of ICDs did not record and save electrograms (EGMs), leading to a reduced appreciation for the frequency and impact of inappropriate shocks. With the advent and then dominance of primary prevention indications, avoidable shocks assumed a relatively larger proportion of total therapy [78][79][80][81][82][83]. Gradually, publications have increased awareness of the frequency and the diverse range of adverse outcomes associated with avoidable ICD therapy, and have demonstrated that avoidable ICD shocks can be reduced by evidence-based programming of the detection rate, detection duration, antitachycardia pacing (ATP), algorithms that discriminate supraventricular tachycardia (SVT) from VT, and specific programming to minimize the sensing of noise [81][82][83][84][85][86][87][88][89][90][91][92].…”

Prognostic Importance of Defibrillator Shocks in Survivors of Sudden Cardiac Death

“…As reported previously [11], ICD therapy cannot be used as a surrogate marker for mortality in clinical trials involving secondary population. …”

“…Arrhythmic death constituted less than 1 percent of all ICD episodes 11 . On multivariate analysis, the relative risk of all cause mortality (HR, 95% C.I, p) associated with an appropriate (1.06, 0.38 to 1.48, NS) or an inappropriate shock (1.63, 0.48 to 5.46, NS) did not differ significantly from that in patients who have not received any shocks (Table 3).…”

“…Therapies occurring less than 5 minutes apart were considered to be a part of the same arrhythmic episode. The type of therapy (shocks and ATP), number of attempts at ATP, outcomes of ATP, number of shocks, type of shocks (low-energy and/or high-energy) and the result of shocks (effective, ineffective, inappropriate) were recorded in detail [11].…”

Cardiac Arrest Induced by Anti-Bradycardia and Anti-Tachycardia Therapies of an Implantable Cardioverter Defibrillator

“…Lots of studies demonstrated that ATP terminates most of VTs but with a 1% to 7% risk of acceleration or precipitation of these arrhythmias [1,2]. Also, anti-bradycardia therapy can have an intrinsic arrythmogenic risk [3].…”