Use and Abuse of Internal Cardioverter Defibrillators for Primary Prevention

Abstract

Sudden cardiac death (SCD) is one of the leading causes of mortality in developed countries. Internal cardioverter defibrillators (ICDs) have been developed to treat potentially life-threatening ventricular arrhythmias. Multiple randomised trials have been completed to assess the efficacy of primary prevention ICDs in selected populations. In response to the randomised, controlled trials guidelines have been established to help guide physicians in choosing appropriate patients who may benefit from primary prevention ICDs. Unfortunately, many patients who currently fall within the guidelines are either not represented in the clinical trials or disregarded. The morbidity associated with ICD implant is also overlooked and the cost-benefit analyses are exaggerated in favour of ICD implant. This review article summarises major clinical trials addressing primary prevention ICDs, and also highlights the evidence supporting the use and abuse of ICDs.

The DAPA Trial in the Context of Previous Prophylactic ICD Landmark Trials

“…In conclusion, existing data in the area of primary ICD implantation seem to be outdated and are becoming more and more estranged from contemporary cardiology practice. 20 However, repeating the previous clinical landmark trials, randomising patients with LVEF <30% to ICD implantation compared with optimal medical therapy, would now create an ethical dilemma. Despite promising results of novel heart failure drugs (for example, angiotensin receptor-neprilysin inhibitors), withholding an ICD from patients with LVEF <30% would be difficult to defend, especially in younger patients.…”

CSI position statement on management of heart failure in India

“…In particular, only 8% of patients in the control group in the MADIT trial received beta blockers compared to 26% of patients in the ICD group at the one-month follow-up. Similarly, in the MUSTT trial, only 29% of the EPS guided therapy group was prescribed beta-blockers 184 …”

Primary hyperparathyroidism associated with acquired long QT interval and ventricular tachycardia

“…Based on the European Society of Cardiology (ESC) recommendations, the ICD is an option in treatment (among others), in patients with documented VF or hemodynamically not tolerated VT in the absence of reversible causes (IA), in patients with recurrent sustained VT who are receiving chronic optimal medical therapy (normal LVEF, reasonable expectation of survival with good functional status for ≥1 year) (IIa C) and in addition to beta-blockers in LQTS patients who experienced syncope and/or VT while receiving an adequate dose of beta-blockers (IIa B) ( 6 ). Given the inadequate assessment and uncritical approach, a large number of patients are recognized in these recommendations, which in some cases lead to unnecessary ICD implantation ( 7 ). Therefore, the question of the necessity of using defibrillators in non-ischemic cardiomyopathy must be kept open.…”