Effect Of Cardiac Rehabilitation On Functional Capacity For Hypertrophic Obstructive Cardiomyopathy Following Septal Myectomy Surgery

Hypertrophic cardiomyopathy is a prevalent inherited heart disease with ~70% of these patients exhibiting the hypertrophic obstructive cardiomyopathy (HOCM) phenotype. Patients with HOCM exhibit reduced exercise capacity. Septal myectomy surgery is the gold standard treatment for HOCM. However, exercise capacity has been reported to improve in only ~50% of these patients following septal myectomy surgery. Cardiac rehabilitation (CR) is a secondary prevention, interdisciplinary chronic disease management program including a supervised exercise training. In this context, CR participation following septal myectomy surgery may optimize the improvements in functional capacity for patients with HOCM. PURPOSE: To assess the impact of CR participation following septal myectomy surgery on functional exercise capacity in patients with HOCM. METHODS: This is a retrospective study including 19 patients (14 males, 5 females; age 62 ± 14 yrs) with HOCM enrolled in outpatient, phase 2 CR after septal myectomy surgery between 2013 and 2023. Functional capacity was quantified via 6-minute walk test (6MWT) distance. A 6MWT was performed pre- and post-CR. A 10% increase in 6MWT distance from pre- to post-CR was considered clinically significant. RESULTS: Patients completed 28 ± 11 CR sessions. 6MWT distance increased from pre- to post-CR in all patients (421 ± 120 vs. 540 ± 98 m, p < 0.01). 6MWT distance increased from pre- to post-CR by >10% in 84% of the patients in this cohort. The average increase in 6MWT distance from pre- to post-CR was 118 ± 81 m. 6MWT percent predicted distance also improved from pre- to post-CR (74 ± 19% vs 95 ± 13%, p < 0.01). Estimated METs calculated from the 6MWT increased pre- to post-CR (3.0 ± 0.6 vs 3.6 ± 0.5 kcal/kg/hr, p < 0.01). There was no statistically significant relationship between number of CR sessions attended and % change in 6MWT distance (p > 0.05). CONCLUSIONS: Cardiac rehabilitation participation resulted in improved functional capacity in patients with HOCM following septal myectomy surgery.