Effect of preload reducing therapy on right ventricular size and function in patients with arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden cardiac death in young people and athletes. To date, no treatment has proven to slow the progression of the disease. Preload reducing agents such as nitrates and diuretics have shown promising results in preventing training-induced development of ARVC in a murine model. OBJECTIVE: The purpose of this study was to describe our experience with preload reducing therapy in patients with ARVC and symptomatic right ventricular (RV) dysfunction. METHODS: We performed retrospective chart review of prospectively collected registry data and included 20 patients with definite ARVC who had serial echocardiographic measurements and an implantable cardioverter-defibrillator. Six of the 20 patients with RV end-diastolic area (RVEDA) above median (>25 cm2) and New York Heart Association functional class II-IV symptoms were successfully treated with long-term isosorbide dinitrate 5-40 mg tid (at maximum tolerated dose) and hydrochlorothiazide-spironolactone 25-25 mg daily. The main outcomes of interest were RVEDA, RV fractional area change (FAC), and RV outflow tract measurements. Generalized estimating equations with repeated measures were used to identify the association between preload reducing agents and echocardiographic structural progression. RESULTS: Patients who received preload reducing agents (n = 6) were older and had larger RVs with lower FAC at baseline. However, treatment with preload reducing agents was associated with less RVEDA enlargement during mean 3.3 (range 1-6.7) years of treatment in multivariate analysis (% change in RVEDA associated with treatment -7.71; 95% confidence interval -13.29 to -2.13; P = .007). CONCLUSION: Preload reducing agents show promising results in slowing RV enlargement in patients with ARVC and show possible disease-modifying potential.