Effects of Cardiac Contractility Modulation on Right Ventricular and Left Atrial Strain in Patients with Chronic Heart Failure

<b>Background:</b> Cardiac contractility modulation (CCM) is an established therapy for patients with heart failure with a reduced ejection fraction (HFrEF) who are still symptomatic despite guideline-directed medical therapy. It has been described previously that CCM leads to both an improvement of heart failure symptoms as well as of the parameters of left ventricular (LV) function, including LVEF and global longitudinal strain (GLS). However, so far there are no reports describing the effects of CCM on right ventricular (RV) or left atrial (LA) function, respectively. This might be of particular interest as RV global strain (RV GS) and LA strain are important prognostic parameters in heart failure. <b>Methods:</b> Adult patients with heart failure with reduced left ventricular function (LVEF <45%) and a QRS complex <130 ms despite guideline-directed medical therapy and with an indication for CCM were eligible for inclusion into this study. Patients receive a follow-up examination every 3 months, including a standardized echocardiographic examination with a special focus on strain analysis. While the effects of CCM on LV global longitudinal strain have been described before, this analysis reports the findings on the RV and LA strain. <b>Results:</b> Between 30.12.2021 and 10.09.2024, 22 patients were prospectively included in the study. CCM implantation was performed in 19 patients. Under active CCM therapy, there was an improvement in right ventricular global strain (CCM: -13.7 ± 4.5 vs. no CCM: -10.1 ± 5.0; <i>p</i> < 0.05), free wall strain (CCM: -14.6 ± 7.3 vs. no CCM: -10.3 ± 10.2; <i>p</i> < 0.05), left atrium strain rate (CCM: 19.7 ± 1.0 vs. no CCM: 15.3 ± 10.2; <i>p</i> < 0.05), and left atrium strain contraction (CCM: -11.5 ± 7.0 vs. no CCM: -7.1 ± 8.5; <i>p</i> < 0.05), whereas there was no difference in left atrium strain conduit (CCM: -9.0 ± 5.0 vs. no CCM: -8.1 ± 5.4; n.s.). To determine which of these parameters are linked to an improvement of quality of life, as seen in the Kansas City Heart Failure Questionnaire (KCCQ), a regression analysis was performed. It turned out that only the parameters of left atrial (LA) strain (LAS_R and LAS_CT) were significantly associated with improved quality of life, while other echocardiographic parameters, such as LV-EF, LV-GLS, and RV-GS, showed no clear association. <b>Conclusions:</b> CCM therapy is not only associated with improvements of left ventricular function but also restores right ventricular and left atrial strain in patients with HFrEF. Regarding the improvement in quality of life, the increase of LA strain seems to be of special importance.