Abstract 3283: Proximity of Lead Position to Site of Latest Mechanical Activation is Associated With Improvements in Ventricular Dyssynchrony and Function Following Resynchronization Therapy
Background: Left ventricular (LV) lead position for resynchronization therapy (CRT) is routinely done empirically by targeting the posterior-lateral region. Our objective was to test the hypothesis that acute improvements in dyssynchrony and LV function are related to LV lead proximity to site of latest radial activation.
Methods: We studied 42 consecutive heart failure patients referred for CRT with ejection fraction (EF) 19±13%, and QRS 155±26ms (57% Ischemic) before and 24 hours after CRT. Speckle tracking radial strain (GE Corp.) was used to map mechanical activation time from 12 radial sites; 6 at basal and 6 at mid-LV levels. LV lead tip was localized using anatomic landmarks of the coronary sinus from multiple fluoroscopic views during CRT. Concordance was defined as LV lead tip matching the same site as the latest mechanical activation from the 12 radial sites.
Results: Overall, group mean radial dyssynchrony improved from 253±127ms to 53±127ms (p<0.05) after CRT. Among the 34 patients with significant baseline radial dyssynchrony (defined as septal-posterior wall delay ≤ 130 ms), lead position was concordant in 24 and discordant in 10. Concordant lead position resulted in greater improvements in dyssynchrony than discordant lead position (58±80ms* vs. 211±120ms) and a greater acute increase in EF (Δ 6±7%* vs. Δ 2±3%) *p< 0.05 vs discordant lead.
Conclusions: Although empiric LV lead placement for CRT results in acute improvement in LV dyssynchrony overall, concordance of lead position with site of latest activation is associated with greater improvements in dyssynchrony and LV function. These observations have potential clinical implications.