Hypertrophic obstructive cardiomyopathy and dual-chamber pacing: Long termresults in a consecutive serie of 22 patients.

The authors report their experience with dual-chamber pacing in hypertrophy obstructive cardiomyopathy. 22 patients (14 women and 8 men) mean age 60 /- 13 years were implanted between 1992 and 1998. The criteria for pace-maker implantation were the presence of severe sympto ms related with hypertrophy obstructive cardiomyopathy (dyspnea, angina, sy ncope) and left ventricular outflow tract gradient at mean 30 mmHg. Before pacing, all patients received a medical therapy which included beta-brokers or calcium inhibitors. This treatment was considered as ineffective or res ponsible of side effects. Patients were followed-up at mean 35.1+/-20.3 mon ths. During this period, symptoms improved (mean NYHA class 2.7+/-0.5 befor e pacing vs 1.4+/-0.5 after pacing) and left ventricular outflow tract lowe red from 95.4+/-40.8 to 39.3+/-20.5 at 6 months, 34.3+/-23.4 at one year an d 26.5+/-21 at the end of follow-up. Seven patients had RF ablation of atrio-ventricular junction for paroxysmal atrial fibrillation or for lack of hemodynamic improvement with pacing. Th is procedure permits a significative lowering of gradient and a better vent ricular filling. In conclusion, dual-chamber pacing is effective for treatment of hypertroph y obstructive cardiomyopathy when medical therapy is ineffective or bad tol erated at condition of: perfect pacing with permanent ventricular capture and optimal AV delay: RF ablation of AV junction in one third of cases; medical therapy systematically associated in all patients.