So you implanted an implantable cardioverter defibrillator, now what to do with it?

Abstract

This editorial refers to ‘Long-term follow-up on high-rate cut-off programming for implantable cardioverter defibrillators in primary prevention patients with left ventricular systolic dysfunction’ by N. Clementy et al ., on page 968 It is well established that patients with a low ejection fraction, be it ischaemic cardiomyopathy or not, benefit from implantable cardioverter defibrillator (ICD) therapy.1,2 Since the hallmark studies, this has been shown repeatedly in real-world studies and in a meta-analysis.3,4 However, this therapy comes with implant-related complications and the psychological strain of shocks, both appropriate and inappropriate.5 Recently, the relation between shocks and mortality has been investigated. The initial question of who to implant with an ICD is closely followed by many others. Single-chamber or dual-chamber pacing (and sensing)? How many zones to programme? Which cut-off rate (and duration to intervention) should be used? What is the benefit or disadvantage of anti-tachycardia pacing (ATP), and how should this be programmed? Finally, which detection intervals and parameters are optimal to treat all important arrhythmias, while avoiding unnecessary and inappropriate shocks. Most of these questions have never been studied systematically. Ventricular pacing can have detrimental effects in patients with left ventricular dysfunction and should be avoided. It is clear now that pacing should be atrial, or at 40 b.p.m. in the ventricle.6 The effects of zone programming have never been studied as such. In MADIT (Multicenter Automatic Defibrillator Implantation Trial) II, programming was left to physician discretion, and both single- and double-chamber devices were used.1 In SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) only single-chamber devices …