Three dimensional echocardiography documents haemodynamic improvement by biventricular pacing in patients with severe heart failure

Objectives--To quantify the short term haemodynamic effects of biventricula r pacing in patients with heart failure and left bundle branch block by usi ng three dimensional echocardiography. Design--Three dimensional echocardiography was performed in 15 consecutive heart failure patients (New York Heart Association functional class III or IV) with an implanted biventricular pacing system. Six minute walk tests we re performed to investigate the effect of biventricular pacing on exercise capacity. Data were acquired at sinus rhythm and after short term (2-7 days ) biventricular pacing. Results--Compared with baseline values, biventricular pacing significantly reduced left ventricular end diastolic volume (EDV) by mean (SD) 4.0 (5.1)% (p < 0.01) and end systolic volume (ESV) by 5.6 (6.4)% (p < 0.02). Mitral regurgitant fraction was significantly reduced by 11 (12.1)% (p <less than> 0.003) and forward stroke volume (FSV) increased by 13.9 (18.6)% (p < 0.02 ). Exercise capacity was significantly improved with biventricular pacing b y 48.4 (43.3)% (p < 0.00001). Regression analyses showed that the percentag e increase in FSV independently predicted percentage improvement in walking distance (r(2) = 0.73, p < 0.0002). Both basal QRS duration and QRS narrow ing predicted pacing efficacy, showing a significant correlation with %Delt a EDV, %Delta ESV, and %Delta FSV. Conclusions--In five of 15 consecutive patients with heart failure and left bundle branch block, biventricular pacing induced a more than 15% increase in FSV, which predicted a more than 25% increase in walking distance and w as accompanied by an immediate reduction in left ventricular chamber size a nd mitral regurgitation.