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 o f non-surgical myocardial reduction in patients with hypertrophic obstructi ve cardiomyopathy. Methods Twenty-five patients with left ventricular outflow tract obstructio n (mean gradient of 84.54 +/- 31.38 mmHg) and symptoms of dyspnoea, angina and/or syncope were treated with non-surgical myocardial reduction. The pat ients were followed-up for a mean period of 10.44 +/- 1.8 months. In all pa tients 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 respirator y gas analysis. Results Clinical follow-up examinations were achieved in ail 25 patients. P ersistent left ventricular outflow tract gradient reduction was seen in 23 patients. Seventeen patients had a reduction of left ventricular outflow tr act gradient >50% of baseline value. Twenty patients showed a clinical impr ovement from 2.8 +/- 0.5 up to 1.2 +/- 0.5 NYHA class (P<0.001). The clinic al improvement was matched by an improvement in objective measures of exerc ise capacity in patients with significant left ventricular outflow tract gr adient 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 wi th exercise capacity improvement was achieved in the majority of patients t reated with nonsurgical myocardial reduction. We recommend this method as a n alternative to surgery for symptomatic patients with hypertrophic obstruc tive cardiomyopathy. (C) 2000 The European Society of Cardiology.