Effects of Cardiac Contractility Modulation Electrodes on Tricuspid Regurgitation in Patients with Heart Failure with Reduced Ejection Fraction: A Pilot Study

Background: Cardiac contractility modulation (CCM) is an innovative therapy for heart failure with reduced ejection fraction delivered by a cardiac implantable device (Optimizer Smart(®)). One of the most prominent periprocedural complications common to all cardiac implantable devices (CIDs) is tricuspid regurgitation (TR) due to the placement of the right ventricular endocardial leads. To date, no published studies have assessed the changes in the TR degree in patients with heart failure with reduced ejection fraction (HFrEF) who received an implantable cardioverter-defibrillator (ICD) after the implantation of cardiac contractility modulation therapy devices. Objective: This study aimed to evaluate the effect of the implantation of the trans-tricuspid leads required to deliver CCM therapy on the severity of TR in patients with HFrEF who previously underwent ICD implantation. Methods: We enrolled 30 HFrEF patients who underwent CCM therapy between November 2020 and October 2021. For all the patients, echocardiographic evaluations of TR were performed according to current guidelines 24 h before and six months after the Optimizer Smart(®) implant was applied. Results: At the 6-month follow-up, the grade of TR remained unchanged compared to the preimplant grade. The value of the vena contracta (VC) of TR was 0.40 ± 0.19 cm in the preimplant period and 0.45 ± 0.21 cm at the 6-month follow-up (p = 0.33). Similarly, the TR proximal isovelocity surface area (PISA) radius value was unchanged at follow-up (0.54 ± 0.22 cm vs. 0.62 ± 0.20 cm; p = 0.18). No statistically significant difference existed between the preimplant VC and PISA radius values, irrespective of the device type. Conclusions: The implantation of right ventricular electrodes for the delivery of CCM therapy did not worsen tricuspid regurgitation in patients with HFrEF and ICD.