Treatment of Obstructive Hypertrophic Cardiomyopathy Symptoms and Gradient Resistant to First-Line Therapy With β-Blockade or Verapamil

Background— There is controversy about preferred methods to relieve obstruction in hypertrophic cardiomyopathy patients still symptomatic after β-blockade or verapamil. Methods and Results— Of 737 patients prospectively registered at our institution, 299 (41%) required further therapy for obstruction for limiting symptoms, rest gradient 61±45, provoked gradient 115±49 mm Hg, and followed up for 4.8 years. Disopyramide was added in 221 (74%) patients and pharmacological control of symptoms was achieved in 141 (64%) patients. Overall, 138 (46%) patients had surgical relief of obstruction (91% myectomy) and 6 (2%) alcohol septal ablation. At follow-up, resting gradients in the 299 patients had decreased from 61±44 to 10±25 mm Hg ( P <0.0001); New York Heart Association class decreased from 2.7±0.7 to 1.8±0.5 ( P <0.0001). Kaplan–Meier survival at 10 years in the 299 advanced-care patients was 88% and did not differ from nonobstructed patients ( P =0.28). Only 1 patient had sudden death, a low annual rate of 0.06%/y. Kaplan–Meier survival at 10 years in the advanced-care patients did not differ from that expected in a matched cohort of the US population ( P =0.90). Conclusions— Patients with obstruction and symptoms resistant to initial pharmacological therapy with β-blockade or verapamil may realize meaningful symptom relief and low mortality through stepped management, adding disopyramide in appropriately selected patients, and when needed, by surgical myectomy.