Abstract 18632: Stepped Management of Obstructive Hypertrophic Cardiomyopathy in Patients Refractory to Beta-Blockade.
Introduction: B-blockade is first line therapy for pts with symptomatic obstructive hypertrophic cardiomyopathy (HCM). In refractory pts disopyramide (diso) has been shown to reduce left ventricular outflow gradients (LVOTG) and improve symptoms. Selection of diso or invasive therapy is tailored for individual patient.
Methods: We reviewed clinical and echo data in 210 pts from 1991–2009 refractory to b-blockade or verapamil and who required intensive therapy. Mortality in the diso-treated pts was compared to a historical control group of 373 obstructive pts not treated with diso from 4 HCM programs.
Results: 57 pts (27%) were referred for surgery without further pharmacologic therapy because of contraindications, concomitant lesions, or triad of youth + high LVOTG + long mitral leaflets. Operative mortality was 0% and cardiac mortality at 3.2 ± 3.0 yrs was 0.5 %/yr. 153 pts (73%) were treated with diso with follow-up for 4.5 ± 3.9 years (504 ± 36 mg/d; 92% also on b-blocker; 15% with additional DDD pacing for LVOTG reduction). There was a reduction in LVOTG from 73 ± 37 to 27 ± 30 mm Hg (p < 0.0001) with improvement in NYHA (p < 0.0001) and QOL (p < 0.0001). Long term 108 pts (71%) could be managed pharmacologically without the necessity for septal reduction with a persistent low LVOTG 22 ±27 mm Hg (p < 0.0001); but, 45 (29%) required septal reduction for symptom relief. The 153 pts treated with stepped-strategy including diso had a lower annualized all-cause cardiac mortality than the 373 pts not treated with diso 1.2 vs. 2.8%/y (HR 0.45, p=0.03). Cardiac deaths in diso pts occurred in elderly, 77 ± 6 yrs. There was also a decrease in annualized sudden death or appropriate ICD therapy, 0.3 vs. 1.7%/y (HR 0.15, p=0.003).
Conclusion: In pts refractory to b-blockade clinical criteria allow selection of pts either for diso treatment, or for surgery without any further pharmacologic therapy, in this series with a ratio of 70:30. All-cause cardiac and sudden death mortality was low in both groups. Therapeutic doses of diso decrease LVOTG and improve symptoms with two-thirds of pts managed without invasive intervention but a third require septal reduction. Observational studies suggest that gradient-lowering therapy is associated with decreased incidence of cardiac and sudden death.
- © 2010 by American Heart Association, Inc.