Echocardiographic Studies of Hemodynamic Changes in Hypertrophic Obstructive Cardiomyopathy Treated by Pacemarker.

Using ultrasound method to judge the mechanism of changes in hypertrophic constructive cardiomyopathy (HCM) with pacing.4 HCM patients they had received left ventricular (LV) catheterization and angiography were examined as followes echocardiographic parameters:①The shape and motion of LV obstructive muscles before and after pacing.②To measure the program of LV segments to be excited,when the atrial ventricular interval were changed by DDD pacemarker.③To measure the variation of LV function at sinus rhythm and pacing controlled.Result:①The gradient at obstructed region were decreased from 161.5±47.4 to 76.3±52.8 mmHg( P 0.05),but the hypertrophic muscles still contracted to obstruct LV outflow during pacing.②The program of exciting LV muscles controlled by DDD pacemarker was not different from that by sinus rhythm,but the interval of conduction course were prolonged (from 45.5±7.7 to 62.5±7.4 ms, P 0.05). ③Some of LV functions turned to be inhibited.Conclusion:Pacing interrupted the normal course of cardiac muscles in conducting,exciting and contracting,so the synchronization ought to be worse than it controlled by physiological program,that LV systolic pressure and gradient of HCM could be decreased.