Percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: Acute results and three-year noninvasive follow-up in 18 patients.

OBJECTIVES: To study the acute results and long-term clinical course after percutaneous transluminal septal myocardial ablation (PTSMA) in symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODS: In 18 patients (seven women, 11 men; average age 53+/-15 years) with symptomatic and medically refractory HOCM, 1.3+/-0.4 septal branches were occluded with an injection of 3.6+/-1.2 mL of 95% alcohol to ablate the hypertrophied interventricular septum. After three years, noninvasive follow-up results of clinical course, echocardiographic and electrocardiographic findings were determined.

RESULTS: The invasively measured left ventricular outflow tract (LVOT) gradients were reduced in all patients, with a mean decrease from 79+/-21 mmHg to 11+/-8 mmHg at rest (P<0.01) and from 136+/-41 mmHg to 49+/-21 mmHg after extrasystole. All patients had angina pectoris for 8 h to 24 h. Eleven patients (61.1%) developed a trifascicular block for 3 min to four days requiring temporary (n=10 [56%]) or permanent dual chamber pacemaker implantation (n=1 [6%]). All patients were discharged after 5.9+/-2.3 days. Clinical, electrocardiographic and echocardiographic follow-up was achieved in all patients after three years (3.1+/-0.5 years). No cardiac complications occurred. Thirteen patients (72%) showed clinical improvement, with a New York Heart Association functional class of 1.5+/-0.8. A further reduction in LVOT gradient was shown in eight patients (44%).

CONCLUSIONS: The LVOT gradient was greatly reduced in patients with HOCM undergoing a PTSMA procedure and their symptoms were greatly improved without cardiac complications during three-year follow-up. Possible complications include different degrees of heart block, such as trifascicular blocks, requiring temporary pacemaker implantation. PTSMA is a promising nonsurgical method for the treatment of symptomatic patients with HOCM. Clinical long-term follow-up of a larger series of patients is required to determine the therapeutic significance conclusively.