Pressure-guided nonsurgical myocardial reduction induced by small septal infarctions in hypertrophic obstructive cardiomyopathy

OBJECTIVES We sought to assess the safety and efficacy of pressure-guided nonsurgical myocardial reduction (NSMR) with the induction of small septal infarctions in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND Nonsurgical myocardial reduction has been shown to decrease left ventricular outflow tract (LVOT) obstruction and to improve symptoms in patients with HOCM. Infarct sizes differ considerably among studies published so far. METHODS In 50 patients, the LVOT gradient was invasively determined at the time of the intervention, four to six months (n = 49) and 12 to18 months (n = 25) after NSMR. New York Heart Association functional class and quality of life were assessed by using a standard questionnaire. Exercise capacity was tested by spiro-ergometry. Left ventricular (LV) mass was determined by electron beam computed tomography. RESULTS Small septal infarctions (mean creatine kinase value 413 ± 193 U/l) resulted in a sustained decrease in LVOT gradients, from 80 ± 33 to 18 ± 17 mm Hg after four to six months (p < 0.001, N = 49) and to 17 ± 15 mm Hg (p < 0.001, N = 25) after 12 to 18 months. Nonsurgical myocardial reduction was followed by a decrease in LV hypertrophy, which was associated with a sustained increase in exercise capacity, as well as improvement in quality of life. CONCLUSIONS Pressure-guided NSMR inducing small septal infarctions was sufficient to result in a sustained decrease in LVOT obstruction and to improve symptoms. The incidence of complications, such as complete heart block with necessary permanent pacemaker implantation (<10%), seems to be diminished by minimizing the infarct size.