Left ventricular outflow tract gradient decrease with non-surgical myocardial reduction improves exercise capacity in patients with hypertrophic obstructive cardiomyopathy

Objectives This study was undertaken to evaluate midterm clinical results of non-surgical myocardial reduction in patients with hypertrophic obstructive cardiomyopathy. Methods Twenty-five patients with left ventricular outflow tract obstruction (mean gradient of 84.54 +/- 31.38 mmHg) and symptoms of dyspnoea, angina and/or syncope were treated with non-surgical myocardial reduction. The patients were followed-up for a mean period of 10.44 +/- 1.8 months. In all patients clinical examination with echocardiography was repeated after every 3 months of follow-up, and a symptom-limited treadmill test was repeated at the 6 month follow-up. Eighteen patients underwent simultaneous respiratory gas analysis. Results Clinical follow-up examinations were achieved in ail 25 patients. Persistent left ventricular outflow tract gradient reduction was seen in 23 patients. Seventeen patients had a reduction of left ventricular outflow tract gradient >50% of baseline value. Twenty patients showed a clinical improvement from 2.8 +/- 0.5 up to 1.2 +/- 0.5 NYHA class (P<0.001). The clinical improvement was matched by an improvement in objective measures of exercise capacity in patients with significant left ventricular outflow tract gradient reduction. Exercise time increased from 571.9 +/- 192.2 to 703.5 +/- 175.4 s, P<0.001, and peak VO2 increased from 14.6 +/- 5.2 to 20.5 +/- 8.6 ml . kg(-1) min(-1), P<0.05. Conclusion Significant left ventricular outflow tract gradient reduction with exercise capacity improvement was achieved in the majority of patients treated with nonsurgical myocardial reduction. We recommend this method as an alternative to surgery for symptomatic patients with hypertrophic obstructive cardiomyopathy. (C) 2000 The European Society of Cardiology.