Pressure-volume loop analysis during implantation of biventricular pacemaker/cardiac resynchronization therapy device to optimize right and left ventricular pacing sites

To evaluate the clinical utility of pressure-volume loop analyses during pacemaker/implantable cardioverter defibrillator (ICD) implantations to assess the optimal right ventricular (RV) and/or left ventricular (LV) lead position. 29 patients with heart failure and chronic RV apical pacing were studied. Stroke work (SW), LV ejection fraction (LVEF), cardiac output (CO), and LV dP/dt(max) were assessed using a conductance catheter in the LV during RV apical, RV outflow tract, single-site LV, and biventricular pacing at different left-sided pacing locations. Left ventricular ejection fraction was 34.3 +/- 9.8%. Compared with baseline, RV outflow tract pacing showed a small increase of 4.0 +/- 6.4% in LV dP/dt(max) and no improvement in SW, LVEF, or CO. In the optimal biventricular configuration, SW increased 39 +/- 41%, LVEF increased 22 +/- 13%, CO increased 16 +/- 16%, and LV dP/dt(max) increased 10 +/- 11% (all P < 0.05). In 45% of the patients, the optimal LV lead position was found at a different location as the 'first choice' postero-lateral or lateral target vein. Pressure-volume loop analysis during pacemaker/ICD implantations facilitates to determine the optimal LV pacing site. Patients with chronic RV pacing showed a significant acute improvement in LV function when LV pacing or biventricular pacing is applied.