Disopyramide Revisited for Treatment of Symptomatic Obstructive Hypertrophic Cardiomyopathy: Efficacy and Safety in Patients Treated for at Least 5 Years.

backgroundDisopyramide is used to treat heart failure symptoms in patients with obstructive hypertrophic cardiomyopathy (HCM) with known medium-term efficacy and safety, while long-term outcomes are unknown. METHODS AND

resultsA total of 92 consecutive patients with symptomatic obstructive HCM with peak left ventricular outflow tract gradients of ≥30 mm Hg at rest or with provocation who were maintained on disopyramide for ≥5 years at 2 dedicated HCM centers were included: 92 patients; mean age, 62.5 years; 54% women; treated with disopyramide for median 7.2 years (left ventricular wall thickness 18±4 mm; median peak outflow gradient 95 mm Hg). At last follow-up, 62 (67%) patients continued disopyramide, including 57 with symptom improvement ≥1 New York Heart Association class. The other 30 (33%) patients discontinued disopyramide due primarily to incomplete symptom resolution and required surgical myectomy or alcohol septal ablation (n=23) at 7.4 years from initiation. With disopyramide, resting left ventricular outflow gradients were reduced by 37% (to median 19 mm Hg), and provoked gradients decreased by 57% (to median 41 mm Hg), with no residual outflow obstruction (<30 mm Hg at rest or with provocation) in 42 (46%) patients and no change in ejection fraction (69%±6% versus 69%±9%,

conclusionsIn patients with obstructive HCM, disopyramide is safe and effective at relieving heart failure symptoms from outflow obstruction in a subgroup of patients who were maintained on disopyramide for >5 years.