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 mid-term 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±31·38mmHg) 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 all 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±175·4s, P <0·001, and peak VO2increased from 14·6±5·2 to 20·5±8·6ml.kg−1min−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 non-surgical myocardial reduction. We recommend this method as an alternative to surgery for symptomatic patients with hypertrophic obstructive cardiomyopathy.