Abstract 13277: Beneficial effects on Aerobic Capacity and Threshold Heart Rate for Arrhythmias from Exercise Training in Patients with Catecholaminergic Polymorphic Ventricular Tachycardia

Abstract

Background Patients with Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) have an increased risk of ventricular arrhythmias (VA) triggered by exercise. During exercise testing, these arrhythmias occur at an individual heart rate (HR). We hypothesized that this threshold HR for arrhythmias may be influenced by systematic exercise. Furthermore, we explored if the HR for arrhythmias could be employed to create an individualized exercise training program without risk of adverse events.

Methods We included 13 patients with confirmed CPVT-causing mutations in the ryanodine receptor 2 gene on optimal medical treatment. The threshold HR for VA was identified for each patient as the HR when bigeminal ventricular extrasystoles or more severe VAs occurred during exercise testing. Six patients were enrolled in an exercise program with ergometer bicycling over 12 weeks (3 x 60 minutes / week). Each session consisted of 4 6-minute intervals at 80-90 % of HR 5 beats per minute (bpm) below threshold HR for arrhythmias, interspersed with three-minute rest periods at 60 %. Seven CPVT patients performed exercise testing at baseline and after 3-12 months with unaltered advice to avoid intense physical and emotional stress and served as control group.

Results: Baseline threshold for occurrence of VA was 100±6 bpm in the training group and 135±4 bpm in the control group. The training patients completed 28±3 sessions (78±8 % program completion) and obtained 12.4±3.2 % increase in VO₂max (17.9±5 % vs. 20.2±5 %, P<0.05). No change in VO₂max was observed for control patients (29.8±5 vs 30.8±5). No adverse events occurred during training sessions. The threshold HR for VA after the training period was 111±10 bpm in training patients and 123±6 bpm in sedentary controls. The threshold for occurrence of VA increased in training patients compared to controls (+11 vs -12 bpm, P<0.05).

Conclusion Patients with CPVT improved their aerobic capacity through an individualized exercise program without occurrence of adverse events. Threshold for occurrence of VA was increased in CPVT patients after a 12 weeks exercise program compared to sedentary CPVT patients. These findings may indicate a positive impact of training on occurrence of arrhythmias in patients with CPVT.