Coronary sinus lead tracking for its 3D dynamic position assessment in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has been successfully used in patients affected by heart failure and left ventricular (LV) systolic dysfunction with LV dissyncrony. However, a variable number of patients (20%-30%) do not respond favorably to CRT due to several possible, still uncertain factors. One possible cause is the displacement of the electrode tip from effectively resynchronizing stimulation sites. In this study we (1) developed a procedure aimed at quantifying the coronary sinus (CS) lead tip position in the 3D domain throughout the cardiac cycle and (2) tested this procedure by comparing the CS lead position at device implantation (t₀) and at three-months follow-up (t₁) using chest fluoroscopy. Our procedure for the assessment of the CS lead position was successfully applied to ten patients. The accuracy resulted in 0.8±0.4 mm, giving a resolution of 1.7 mm. The repeatability was 0.4±0.4 mm. Six patients were evaluated at follow-up and the qualitative check of displacement from fluoroscopy videos did not contradict our quantitative analysis. The proposed technique allowed quantitative evaluation of CS lead position and tracking in 3D space.