Prediction of cardiac resynchronization therapy response by means of 3D trajectory assessment of the coronary sinus lead

Cardiac resynchronization therapy (CRT) is an effective treatment for chronic symptomatic systolic heart failure with cardiac dyssynchrony, but about one-third of patients do not respond favorably to the therapy. We tested the hypothesis that changes in the movements of coronary sinus (CS) electrode tip during the cardiac cycle, induced by the start of biventricular pacing could be related to resynchronization process and predictive of CRT response. In 13 CHF patients submitted to CRT implant, a previously validated method for CS lead tracking throughout cardiac cycles in 3D was applied, before (t
_-1
) and immediately after (t
₀
) the turn-on of biventricular pacing. The variations in several parameters describing CS lead's 3D trajectory at t
₀
with respect to t
_-1
were compared between echo responder and non-responder patients. Preliminary data showed a significantly more circular and smooth trajectory as an immediate result of the CRT turning-on in the echo-responder group. Therefore, 3D trajectories could describe features of resynchronization start-up in CRT recipients and could help to understand the reasons of therapy failure in non-responder patients.