Implantation of CARILLON ® Mitral Contour System with transvenous left ventricular lead in place.

BACKGROUND: Cardiac resynchronisation therapy (CRT) is an established treatment option for chronic heart failure patients with left bundle branch block. Although a concomitant functional mitral regurgitation is often reduced by CRT, many patients need additional mitral valve repair. Placing a CARILLON® Mitral Contour System (CMCS) over a transvenous CRT lead is currently not recommended, since both of them are implanted in the coronary sinus (CS). The aim of this study was to investigate the feasibility of sequential implantation of a transvenous LV lead followed by CMCS implantation, and to assess LV lead performance and possibility of extraction.

METHODS AND RESULTS: Standard transvenous LV leads were implanted in the CS of five female sheep. After establishing regular anatomical position with stable electrical parameters of the LV lead, a CMCS was additionally implanted in the CS. After an observation period of 100 days, lead performance and positions of lead and CMCS were studied. Sequential implantation of the two components was feasible in sheep. After 100 days, all leads showed regular measurements of impedance, threshold, and sensing. There was no migration of either the LV lead or the CMCS. In all cases, the LV lead could be completely extracted without migration of the CMCS. There were no acute or long-term complications.

CONCLUSIONS: In an animal model of healthy adult sheep, implantation of CMCS with a transvenous LV lead already in place was feasible and without major problems with either the CMCS or the LV lead. Electrical performance of the LV leads was excellent. All LV leads could be extracted without migration of the CMCS.