Cardiac resynchronization therapy left ventricular lead through middle cardiac vein: A feasibility study with short-term follow-up

Purpose: The benefits of cardiac resynchronization therapy (CRT) depend on multiple factors including patient selection and left ventricular (LV) lead position in the coronary sinus. The ideal position for stimulation is the posterolateral region of the left ventricle, since this is the site where maximum contractile delay is seen. But this ideal site of LV lead placement is not possible in many patients due to anatomical limitations. Our study evaluated the feasibility of the middle cardiac vein (MCV) as an alternative target for LV lead placement with short-term outcomes result in a small cohort of patients. Methods: This is a single-center experience over a span of 2 years where in patients with anatomical limitations, we positioned our LV leads through MCV. In this period, we had implanted a total of 76 CRTs in our institution, out of which 6 cases we used MCV. We utilized collateral circulation to reach as close possible to the lateral surface of the left ventricle. Right ventricular (RV) leads were positioned to either outflow tract or upper septum to enhance the electrical gap in between two ventricular leads. Results: We achieved satisfactory periprocedural end results in all the cases as evident by appropriate threshold/impedances of all the leads, lack of diaphragmatic stimulation, etc. There were no procedural complications. Optimum short- and midterm improvement of symptomatic class and LV ejection fraction was observed. None of the patients had any lead dislodgement, abnormal change in lead threshold parameters, or need for hospitalizations for heart failure in follow-ups. Conclusion: We conclude that when usual posterolateral or lateral target veins cannot be accessed for LV lead placement, as an alternative approach utilizing MCV collateral circulation to reach as close possible to the lateral surface may be considered in CRT. RV leads to be positioned at the outflow tract or upper septum in those cases.