OPERATIVE TREATMENT OF PEDIATRIC OBSTRUCTIVE HYPERTROPHIC CARDIOMYOPATHY - A 26-YEAR EXPERIENCE

We retrospectively reviewed the 26-year National Institutes of Health experience with operative treatment of obstructive hypertrophic cardio myopathy in pediatric patients. Operative criteria were either severe obstructive symptoms (New York Heart Association functional class III or IV) or sudden death. Seventeen patients undenwent 19 open procedure s, of which the present study is comprised. Complete follow-up was ava ilable 10.1 +/- 1.4 years (mean +/- standard error; range, 0.8 to 26.2 years) after operation. The mean ages at diagnosis and operation were 11.9 +/- 1.3 years (range, 1 to 17 years) and 14.8 +/- 0.7 years (ran ge, 9 to 17 years), respectively. The preoperative intraventricular se ptum mean dimension was 23.2 +/- 1.3 mm (range, 11 to 36 mm). The left ventricular outflow tract gradient was 74 +/- 9 mm Hg (range, 20 to 1 75 mm Hg) at rest and 94 +/- 7 mm Hg (range, 55 to 175 mm Hg) with pro vocation. Fifteen patients (88%) underwent left ventricular myotomy an d myectomy, and 2 underwent mitral valve replacement. Two patients who initially received left ventricular myotomy and myectomy later underw ent mitral valve replacement. There were one perioperative death (6%) and five late sudden deaths (31%) at 3.8, 8.7, 9.6, 14.1, and 21 years postoperatively. Kaplan-Meier survival was 86% +/- 8% at 5 years and 77% +/- 12% at 10 years. After operation, the left ventricular outflow tract gradient decreased almost 80% to 21 +/- 15 mm Hg (p = 0.0001). In 8 patients, the left ventricular outflow tract gradient completely resolved. The New York Heart Association functional class was markedly improved (2.9 +/- 0.2 preoperatively to 1.1 +/- 0.1 postoperatively a nd 1.5 +/- 0.1 at 10.1 +/- 1.4 years; p = 0.0001). These data show tha t operative treatment of obstructive hypertrophic cardiomyopathy in ch ildren is safe and effective palliation. The high rate of late, and pr esumably arrhythmia-related, sudden death warrants close follow up wit h early aggressive treatment of arrhythmia.