Long-term follow-up on high-rate cut-off programming for implantable cardioverter defibrillators in primary prevention patients with left ventricular systolic dysfunction.

Aims: Implantable cardioverter defibrillators (ICDs) are efficient in reducing mortality in patients with left ventricular systolic dysfunction. High-rate cut-off programming may be effective in reducing appropriate and inappropriate therapies, but as the long-term consequences on morbidity and mortality remain unclear, it is underutilized.

Methods And Results: We prospectively studied 365 consecutive patients (mean age 60 ± 10 years), with ischaemic (63%) or non-ischaemic cardiomyopathy and left ventricular dysfunction (mean ejection fraction 25 ± 7%), who were implanted with an ICD in primary prevention of sudden cardiac death (41% single chamber, 31% dual chamber, and 28% biventricular). All devices were programmed with a shock-only zone over 220 beats per minute (b.p.m.) and a monitoring zone between 170 and 220 b.p.m. During a median follow-up of 40 months, 41 patients received appropriate shocks (11.2%) and 24 inappropriate shocks (6.6%). Then, 306 patients never experienced any ICD shock (84%). Inappropriate discharges were related to supraventricular tachyarrhythmia in 10 patients, and noise/oversensing in 14 patients. Ventricular tachycardia episodes, sustained or not, were recorded in the monitoring zone in 43 patients (11.8%). Seven of these patients were symptomatic (1.9%), without lethal consequence. Sixty-two patients (17%) died: 35 from end-stage heart failure, 1 from unexplained sudden death, and 26 from a documented non-cardiac cause.

Conclusion: High-rate cut-off (220 b.p.m.) shock-only ICD programming, in primary prevention patients with reduced left ventricular ejection fraction, appeared to be safe during a long-term follow-up. It also resulted in a very low rate of discharges, which are known to be deleterious in this population.