ICD R-WAVE DETERIORATION IN ARVC PATIENTS - DETERMINING THE OPTIMAL ICD LEAD PLACEMENT

Abstract

Conventional implantable cardioverter defibrillator (ICD) implanters target the apex for the placement of the right ventricular (RV) ICD lead. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive disease where healthy myocardium is replaced by fibrofatty tissue in the triangle of dysplasia, a region that includes the apex of the RV. Conventional wisdom suggests that RV leads should avoid the triangle of dysplasia as fibrofatty tissue replacement may result in a decrease in R-wave sensing for the ICD, and the inability of the ICD to detect potentially lethal arrhythmias and subsequently deliver life-saving therapy. This study compared ARVC patients to patients with structurally normal hearts, comparing R-wave amplitude over long-term follow-up. A retrospective chart review was performed from four major inherited arrhythmia clinics across Canada. The R-wave of ARVC patients were compared to patients with structurally normal hearts (control), including Long QT Syndrome (LQTS) and Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT). R-wave values were compared between years 1 and 2 post-implantation, and years 5 and 6 post-implantation using mixed-effect models adjusted for age and sex. 77 ARVC (55% male, 43.7±15.0 years) patients were compared to 46 patients with structurally normal heart35% male, 41.6±13.6 years). Mixed-effects models were constructed in Figure 1 and compared between the ARVC group (Figure 1A) and the control group (Figure 1B). There was no difference in R-wave when comparing the ARVC group and the control group at years 1 and 2 post-implantation years (8.56±4.20 mV and 8.43±3.72 mV retrospectively), however the ARVC group showed significant deterioration in amplitude compared to the control group at years 5 and 6 (7.53±3.83 mV and 9.67±3.92 mV, p=0.02, Figure 1). There was no difference in impedance between the two groups over a similar follow-up time (p=0.82). Long-term follow-up of RV lead performance in ARVC patients shows a decline in R wave amplitude compared to controls. Implanters should target regions outside of the apex when implanting ICD RV leads in ARVC patients.