Background: Non-surgical septal reduction (NSMR) is a new method of treatment in patients with hypertrophic obstructive cardiomyopathy (HOCM). The long-term outcome of patients undergoing this procedure has not yet been well established.
Aim: To assess the short- and long-term results of NSMR in HOCM.
Methods: Early and late (3-year) outcome after NSMR was assessed in 59 and 44 consecutive patients with HOCM, respectively. Control out-patient visits were scheduled 3, 6, and 12 months after NSMR, and annually thereafter. All patients had repeated ECG, echocardiography, 24-hour ambulatory ECG monitoring and spiro-ergometric tests.
Results: Left ventricular outflow tract (LVOT) gradient, measured invasively directly after the procedure, decreased from 79.5+/-29.6 to 26.2+/-18.5 mmHg (p<0.0001). A significant LVOT gradient reduction was achieved in 51 (86%) patients. A complete a-v block occurred in 17 (29%) patients, of whom 7 (12%) underwent dual-chamber pacemaker implantation. A significant decrease in exertional dyspnea and angina was observed three months after NSMR (NYHA class reduction from 2.9+/-0.2 to 1.4+/-0.7, p=0.001 and CCS class reduction from 2.3+/-0.3 to 0.5+/-0.7, p=0.001, respectively). Of the 45 patients who were followed for > or =3 years, one patient died due to lung disease whereas no sudden deaths or life-threatening ventricular arrhythmias were observed. LVOT gradient was further reduced, and three years after NMSR disappeared in 35 (59%) patients. A significant improvement in physical capacity was noted (peakVO(2) increased from 14.1+/-3.8 ml/kg/min before NSMR to 23.2+/-6.2 three years later, p=0.02). Favourable LV remodelling was observed, causing LVOT dilatation and an increase in LV diastolic volume.
Conclusions: Because NSMR causes a significant reduction of LVOT gradient, an increase in physical capacity in >80% of patients and the long-term follow-up is uneventful, it may be regarded as an alternative procedure to myectomy in the treatment of patients with HOCM.