Evaluating deceleration and acceleration capacities: Implications for predicting adverse outcomes in patients with hypertrophic cardiomyopathy.

Background: Abnormal cardiac autonomic function is commonly observed in patients with hypertrophic cardiomyopathy (HCM); however, its association with poor prognosis remains unclear. The deceleration capacity (DC) and acceleration capacity (AC) of the heart rate are promising measures reflecting parasympathetic and sympathetic activity of the heart.

Objective: This study aimed to determine whether DC and AC can predict adverse outcomes in patients with HCM.

Methods: In this prospective observational cohort study, 856 unrelated patients with HCM were enrolled between 2013 and 2022. The primary outcome was all-cause death, while the secondary outcome was cardiovascular death. Cox regression analysis assessed the associations of variables and clinical outcomes.

Results: During a median follow-up of 3.0 years (interquartile range: 2.3-3.9), there were 25 cases of all-cause death and 17 cases of cardiovascular death. Lower values of DC showed strong unadjusted associations with the higher risk of all-cause death (hazard ratio [HR] = 1.391 [1.131-1.712], P = .002) and cardiovascular death (HR = 1.311 [1.017-1.689], P = .036). After adjustment, DC remained predictive for all-cause death (adjusted HR = 1.330 [1.072-1.650], P = .010). Consistently, AC predicted higher risk for both end points (all-cause death: HR = 1.458 [1.195-1.779], P < .001; cardiovascular death: HR = 0.404 [1.104-1.789], P = .006), and the association with all-cause death persisted after adjustment (adjusted HR = 1.391 [1.133-1.709], P = .002).

Conclusion: DC and AC are independent predictors of the high mortality risk in patients with HCM, suggesting their clinical utility as electrophysiological markers for identifying high-risk individuals in this population.