Response to Letter by Dr. Karam Ayoub, MD

We thank Dr. Ayoub, for his questions regarding our recently published trial¹.

1. The difference between the usual care (UC) and exercise (EX) groups in their receipt of implantable cardioverter defibrillator (ICD) shocks was not statistically different during the study period. However, there were few ICD shocks in both groups, limiting the power for this comparison. A slightly higher proportion of patients in the EX as compared to the UC group were taking anti-arrhythmic medications at baseline study entry. The anti-arrhythmic medication taken in both groups was amiodarone, with 1 person in the EX group also taking mexilitene.

2. Patients were receiving a variety of beta blocker medications on study entry, these did not differ significantly between the EX and UC groups: (Atenolol, 3 in each group, Bisoprolol, 1 in UC and 0 in EX, Carvedilol, 36 in EX and 35 in UC, Metoprolol, 31 in EX and 32 in UC, Nebivolol, 0 in EX and 2 in UC, Sotolol, 4 in EX and 3 in UC).

3. When we stratified patients by ICD indication (primary vs. secondary), in primary prevention there were 2 total shocks in 2 individuals: 1 shock in UC and 1 shock in EX. In secondary prevention, there were 10 total shocks: 7 shocks in 3 individuals in UC and 3 shocks in 2 individuals in EX. These differences were not statistically significant.