Dual-Chamber pacing for postoperative residual left ventricular gradient after aortic valve replacement and concomitant septal myectomy for severe aortic stenosis and subvalvular obstruction.

BACKGROUND: Aortic stenosis is occasionally associated with subvalvular obstruction and remaining obstruction may at times be found after aortic valve replacement. CASE REPORT: A 69-year-old woman with a history of several episodes of unconsciousness was admitted because of exertional chest oppression. The echocardiography revealed severe aortic stenosis (flow velocity 6.2 m/sec, maximum / mean pressure gradient 152 / 99 mmHg, valve area 0.59 cm2) as well as gradient within the left ventricular cavity from the mid ventricular level (flow velocity 4.5 m/sec, maximum gradient 82 mmHg). Despite aortic valve replacement and concomitant septal myectomy which was thought adequate in reducing subvalvular pressure gradient during surgery, postoperative echocardiography revealed significant residual mid ventricular gradient (flow velocity 4.9 m/sec, maximum gradient 95 mmHg). It was decided to implant dual-chamber pacemaker, which resulted in significant reduction of residual mid ventricular gradient (flow velocity 1.4 m/sec, maximum gradient 8 mmHg). CONCLUSION: Dual-chamber pacing was extremely effective in reducing residual mid ventricular gradient in a patient who underwent aortic valve replacement and concomitant septal myectomy for severe aortic stenosis and subvalvular obstruction..