UMEM Educational Pearls

Advances in Hypertrophic Cardiomyopathy (HCM)

- HCM is a genetically transmitted autosomal dominant disorder with two variants: hypertrophic obstructive cardiomyopathy (HOCM), also known as idiopathic hypertrophic subaortic stenosis (IHSS) or asymmetric septal hypertrophy, and non-obstructive hypertrophic cardiomyopathy (HNCM), also known as Yamaguchi syndrome.

- The most serious complication of both variants of HCM is sudden cardiac death (SCD) and end-stage heart failure, which rapidly progresses to cardiac death after its occurrence.

- Beta-blockers (1st line) and non-dihydropyridine calcium channel blockers are effective at improving clinical symptoms (syncope, dyspnea, chest pain, and exertional intolerance, etc.) however neither alone nor combined halt the progressive LV remodeling and prevent end-stage heart failure.

- Cardiac transplantation is the only treatment available for end-stage heart failure, but must occur before the onset of pulmonary hypertension, kidney malfunction, and thromboembolism for success.

- Class Ia anti-arrhythmic, disopyramide has been shown to be effective for symptomatic improvement (NYHA classification), but does not improve overall LV function or hypertrophy.

- A recent study found that another class Ia anti-arrhythmic, cibenzoline has been shown not only to reduce symptoms, but also improved LV diastolic dysfunction and induced a regression of LV hypertrophy. In this study cibenzoline has halted the progression of HCM to end-stage heart failure. 

References

Hamada M, Ikeda S, et al. Advances in medical treatment of hypertrophic cardiomyopathy. Journal of Cardiology. July 2014 (64):1;1-10.