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+/-31.38 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 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+/-175.4 s, P<0. 001, and peak VO(2)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 non-surgical myocardial reduction. We recommend this method as an alternative to surgery for symptomatic patients with hypertrophic obstructive cardiomyopathy.