Right ventricular lead adjustment in cardiac resynchronization therapy and acute hemodynamic response: a pilot study

Optimal left ventricular (LV) lead position has emerged as an important determinant of response after cardiac resynchronization therapy (CRT). Comparatively, strategy for right ventricular (RV) lead optimization remains uncertain. Three variations of RV lead position (apex, mid-septal, and high septal) were tested in seven consecutive patients. At each location, intra-procedural measurement of LV lead electrical delay (LVLED) was obtained during intrinsic rhythm and RV pacing (RV-LVLED). Simultaneous cardiac output assessment was performed using the LiDCO (TM) (lithium chloride indicator dilution) system. Final RV lead location was selected based on best-measured cardiac output. Clinical and echocardiographic outcomes were assessed at baseline and 6 months. Adjustment of RV lead position after securing a LV lead site led to an incremental change of 30 +/- 18 % (range, 7-52 %) in the cardiac index (CI). There was substantial variation in acute hemodynamic response (a dagger CI, 14 +/- 13 %; range, 3-41 %) seen with pacing from each patient's worst to best RV lead position; no single RV lead position emerged as optimal across all patients. Paced RV-LVLED was not correlated with percent change in CI (r = 0.18; p = NS). LV ejection fraction (LVEF) increased significantly (28 +/- 4 to 40 +/- 8 %, p = 0.006) at 6 months. LVLED measured during intrinsic rhythm, but not during RV pacing, correlated with percent change in LVEF (r = 0.88, p = 0.02). RV lead position adjustment can be used to enhance acute hemodynamic response during CRT. Measurement of paced RV-LVLED, however, does not reliably predict change in cardiac output.