Impact of Exercise Restriction on Arrhythmic Risk Among Patients With Arrhythmogenic Right Ventricular Cardiomyopathy

Area of Science:

• Cardiology
• Genetics
• Exercise Physiology

Background:

• Arrhythmogenic right ventricular cardiomyopathy (ARVC) is linked to exercise.
• The impact of exercise restriction on ventricular arrhythmias (VA) and implantable cardioverter-defibrillator (ICD) decisions in ARVC patients is not fully understood.
• Genotype's role in modifying exercise restriction benefits requires clarification.

Purpose of the Study:

• To investigate the relationship between exercise reduction and ventricular arrhythmias (VA) in ARVC patients with ICDs.
• To determine if genotype influences the effectiveness of exercise restriction in ARVC.
• To assess if exercise modification can defer ICD implantation in ARVC patients.

Main Methods:

• Interviewed 129 ARVC patients with ICDs regarding exercise habits before and after presentation.
• Defined exercise change as the difference in annual exercise duration and dose.
• Monitored for appropriate ICD therapy for VA as the primary outcome over a median follow-up of 5.1 years.

Main Results:

• 74% of patients reduced their exercise dose post-presentation.
• Significant reduction in exercise duration and dose was associated with less VA.
• Greater exercise dose reduction correlated with greater VA reduction (P=0.01 for trend).
• Patients without desmosomal mutations and those with primary-prevention ICDs showed greater benefit from exercise reduction.
• However, 58% of athletes reducing exercise by >80% still experienced VA.

Conclusions:

• Exercise restriction is recommended for all ARVC patients with ICDs.
• Patients who are "gene-elusive" and those with primary-prevention ICDs may particularly benefit from reduced exercise.
• Exercise reduction alone is unlikely to be sufficient to alter ICD implantation decisions in high-risk ARVC patients.