Incidence of infective endocarditis in patients with hypertrophic cardiomyopathy.

Background: Data on the incidence of infective endocarditis (IE) in patients with hypertrophic cardiomyopathy (HCM) is sparse. This study evaluated a HCM cohort with aim to study the incidence of IE in these patients.

Methods: All patients entering the HCM cohort from May 2003 to June 2022 of a tertiary care hospital with at least one follow-up visit were included and followed up till June 2023. This was a retrospective cohort analysis. Only individuals who were diagnosed with IE after entry into the cohort were included.

Results: The study cohort consisted of 529 HCM patients with a total follow up duration of 3244.6 years. The mean and median follow-up durations were 6.1 ± 4.7 and 5.3 (range 31 days to 20.1) years respectively. Three (0.57 %) patients in the cohort developed IE. Incidence of IE in HCM patients was 0.92/1000 patient years. Two patients had left ventricular outflow tract obstruction while one had non-obstructive HCM. None of the patients with isolated mid-cavity gradients developed IE. The incidence of IE in the obstructive and nonobstructive groups was 1.39 and 0.55 per 1000 patient years respectively. Two had vegetations on mitral valve while one had vegetations on aortic valve. Both patients with mitral valve endocarditis developed severe residual mitral regurgitation and heart failure.

Conclusions: IE is a rare complication in HCM patients with an incidence of 0.92/1000 patient years. However, when it occurs, IE is associated with high morbidity and mortality.