Multicenter study of the efficacy and safety of disopyramide in obstructive hypertrophic cardiomyopathy.
OBJECTIVE
In this study we assessed the long-term efficacy and safety of disopyramide for patients with obstructive hypertrophic cardiomyopathy (HCM).


BACKGROUND
It has been reported that disopyramide may reduce left ventricular outflow gradient and improve symptoms in patients with HCM. However, long-term efficacy and safety of disopyramide has not been shown in a large cohort.


METHODS
Clinical and echocardiographic data were evaluated in 118 obstructive HCM patients treated with disopyramide at 4 HCM treatment centers. Mortality in the disopyramide-treated patients was compared with 373 obstructive HCM patients not treated with disopyramide.


RESULTS
Patients were followed with disopyramide for 3.1 +/- 2.6 years; dose 432 +/- 181 mg/day (97% also received beta-blockers). Seventy-eight patients (66%) were maintained with disopyramide without the necessity for major non-pharmacologic intervention with surgical myectomy, alcohol ablation, or pacing; outflow gradient at rest decreased from 75 +/- 33 to 40 +/- 32 mm Hg (p < 0.0001) and mean New York Heart Association functional class from 2.3 +/- 0.7 to 1.7 +/- 0.6 (p < 0.0001). Forty other patients (34%) could not be satisfactorily managed with disopyramide and required major invasive interventions because of inadequate symptom and gradient control or vagolytic side effects. All-cause annual cardiac death rate between disopyramide and non-disopyramide-treated patients did not differ significantly, 1.4% versus 2.6%/year (p = 0.07). There was also no difference in sudden death rate, 1.0%/year versus 1.8%/year (p = 0.08).


CONCLUSIONS
Two-thirds of obstructed HCM patients treated with disopyramide could be managed medically with amelioration of symptoms and about 50% reduction in subaortic gradient over >/=3 years. Disopyramide therapy does not appear to be proarrhythmic in HCM and should be considered before proceeding to surgical myectomy or alternate strategies.
Sherrid
Mark V
MV
St. Luke's-Roosevelt Hospital Center, Columbia University, College of Physicians and Surgeons, New York, New York 10019, USA. msherrid@chpnet.org
Barac
Ivan
I
McKenna
William J
WJ
Elliott
Perry M
PM
Dickie
Shaughan
S
Chojnowska
Lidia
L
Casey
Susan
S
Maron
Barry J
BJ
D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002312:Cardiomyopathy, Hypertrophic / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D016757:Death, Sudden, Cardiac; D004206:Disopyramide / Q000008:administration & dosage / Q000627:therapeutic use*; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D012449:Safety; D016896:Treatment Outcome
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D004206:Disopyramide