Cardiac contractility modulation efficacy: is there a difference between ischemic vs. non-ischemic patients?
Authors: Fastner C , Akin I , Yuecel G , Rudic B , El-Battrawy I , Kruska M , Lang S , Liebe V , Tueluemen E , Borggrefe M , Kuschyk J 
Published: November 2020

Abstract

Background/Introduction
Cardiac contractility modulation (CCM) is an FDA approved device therapy for systolic heart failure patients with narrow QRS complex who are symptomatic despite optimal medical therapy. It is used in patients with a wide range of different cardiomyopathies. However, little is known whether the therapy is comparably effective in different entities.

Purpose
This work investigated the long-term therapeutic effect in patients with ischemic (ICMP) compared to patients with non-ischemic cardiomyopathy (NICMP).

Methods
102 patients of our single center registry with known form of cardiomyopathy were included in this retrospective analysis (from 2011–2019). In 68 patients data of a clinical 3-year follow-up were available. The actual mortality rate within one and three years was compared with the one predicted by the MAGGIC risk score and compared between the two groups. In addition, changes in NYHA class, left ventricular ejection fraction (LVEF), LV end-diastolic diameter (LVEDD) and NT-proBNP values were compared as functional parameters.

Results
Patients with an ICMP (65%) were older (67±1 vs. 57±2 years (SD±SEM); p&lt;0.001) but had a comparable MLHFQ score (42±3 vs. 48±6; p=NS), mean peak VO2 (9.7±1.2 vs. 14.5±2.2 ml/kg/min; p=NS) and QRS width (115±3 vs. 112±4 ms; p=NS). Both groups initially had a comparably advanced limitation during physical activity (median NYHA class III; p=NS); 40% of patients responded with an improvement of at least 1 NYHA class within 3 years (p=NS). The LVEF was 24±1 vs. 22±1% in the beginning and improved to 32±2 vs. 38±2% within 3 years (+33 vs. +73%; p&lt;0.001 in comparison over time; p&lt;0.001 in comparison of the percentage changes ICMP vs. NICMP). While LVEDD was initially significantly wider in NICMP patients (51±2 vs. 67±2 mm; p&lt;0.001), this was offset under therapy, mainly due to a reduction in LVEDD in NICMP patients (+3±2 vs. −7±3 mm; p=0.023). The NT-proBNP values decreased from 4872±776 vs. 5354±1153 to 2051±578 vs. 843±363 ng/l (−58 vs. −84%; p=NS in comparison over time; p=0.093 in comparison of the percentage changes ICMP vs. NICMP). ICMP patients had a higher MAGGIC risk score (27±1 vs. 24±1; p=0.019). Mortality rates at 1 year were 7.4 vs. 17.1% and at 3 years 40.5 vs. 35.5% (each p=NS) compared to mortality rates estimated from the MAGGIC risk score of 21.2 vs. 16.0% (p=0.028) and 44.0 vs. 37.2% (p=0.071), respectively. Chi-square test for comparison of observed and expected frequencies revealed that the number of deaths during 1-year follow-up was significantly lower than predicted only in ICMP patients (p=0.018 compared to the estimated risk).

Conclusions
NICMP patients had a significantly greater increase in LVEF. Moreover, reverse remodeling with reduction of the LVEDD was only observed in NICMP patients. In summary, significant differences in functional therapy response could be identified between ICMP vs. NICMP patients.

Funding Acknowledgement
Type of funding source: None