Left ventricular lead concordance with latest activated segment by equilibrium radionuclide angiography predicts improvement after cardiac resynchronization therapy

Objectives 30% of the patients with advanced heart failure (HF) who receive cardiac resynchronization therapy (CRT) do not show clinical improvement. The equilibrium radionuclide angiogram (ERNA) is an objective and reproducible imaging method that allows for phase analysis to determine the site of latest mechanical activation (LMA) in the LV. We propose that placing the LV lead at the site of LMA will lead to better response rate to CRT.

Methods We studied 35 patients (28 males, mean age 67+/- 14 years) with HF, LVEF < 35% and QRS > 120 ms. ERNA, echocardiograms and NYHA class assessment were performed before and after CRT and patients were followed for > 6 months. LMA segment was determined by ERNA phase analysis, and final lead position was recorded from chest x-ray after lead implantation. Patients were divided two groups based on either concordant (CLP) or discordant lead placement (DLP). Improvement in NYHA class and change in ESVI compared between the two groups and 2-tailed student T test was used to determine p values.

Results LV lead placement and LMA segment were concordant in 20 pts (57%).80% of the CLP pts showed clinical improvement while only 43% of the DLP pts showed clinical improvement. Difference in mean change in NYHA class was significant between the two groups. A subset of 23 pts received echocardiograms before and after CRT. Mean percentage change in ESVI, a marker of LV reverse remodeling, was -21% in CLP pts and +17% in DLP pts, (P < 0.05).

Conclusions HF pts undergoing CRT who received LV lead placement concordant with ERNA derived LMA segment showed greater response in terms of both improvement in NYHA class and change in ESVI.