Acute Hemodynamic Changes Induced by Cardiac Contractility Modulation Evaluated Using the NICaS® System: A Pilot Study

Abstract

Background/Objectives: Heart failure (HF) with reduced ejection fraction remains a significant global health challenge despite advances in medical therapy. Cardiac contractility modulation (CCM) is a promising treatment for symptomatic HF patients who are ineligible for cardiac resynchronization therapy (CRT). Non-invasive methods to assess the acute hemodynamic effects of CCM are critical to optimize care and guide treatment. This study aimed to evaluate the acute impact of CCM on stroke volume (SV) and total peripheral resistance index (TPRI) using the non-invasive bioimpedance-based system (NICaS^®). Methods: Eight HF patients (median age: 64.6 years, median left ejection fraction (LVEF): 34.5%) underwent implantation of the Optimizer Smart Mini CCM device. Hemodynamic parameters, including SV and TPRI, were measured using NICaS^® at baseline (pre-implantation) and at 1 week, 1 month, and 3 months post-implantation. Measurements were repeated eight times per session and analyzed using non-parametric statistical tests, including the Kruskal-Wallis test, Mann-Whitney test, and Kolmogorov-Smirnov test. Results: Median SV increased significantly from 40.02 mL (interquartile range (IQR): 32.62-78.16 mL) at baseline to 69.83 mL (IQR: 58.63-86.36 mL) at 3 months (p < 0.0001). Median TPRI decreased significantly from 2537 dn s/cm⁵ m² (IQR: 1807-3084 dn s/cm⁵ m²) to 1307 dn s/cm⁵ m² (IQR: 1119-1665 dn s/cm⁵ m²) over the same period (p < 0.0001). CCM therapy significantly improved SV and reduced TPRI in HF patients within three months of implantation. Conclusions: NICaS^® provided a reliable, non-invasive tool for monitoring these acute hemodynamic changes, supporting its use in clinical practice.

Keywords: NICaS®; cardiac contractility modulation; heart failure; hemodynamics; non-invasive monitoring.

Figure 1

Descriptive statistics of changes in SV (a,b) and TPRI (c,d) across four time points, presented as (a,c) median with interquartile range and (b,d) mean with standard deviation. The points correspond to each of the eight measurements taken for each of the eight patients.

Figure 2

Bland–Altman plot illustrating the agreement between NICaS^® and echocardiography stroke volume measurements. Each point corresponds to a single paired measurement of stroke volume from NICaS^® and echocardiography. X-axis value is the average of the two measurements for a given observation. Y-axis value is the difference between NICaS^® and echocardiography measurements. The dashed purple line shows the mean difference or bias (4.018 mL). Points above the line indicate that NICaS measured a higher stroke volume than echocardiography for those observations. The black lines indicate the limits of agreement.

Figure 3

Scatter plot with linear regression analysis comparing NICaS^® and Echocardiography SV measurements.