The assessment of left ventricular myocardial work in patients with chronic heart failure receiving cardiac contractility modulation therapy
Authors: Dobrovolskaya S , Saidova M , Safiullina A , Uskach T , Belevskaya A , Tereschenko S 
Published: October 2021

Abstract

Introduction
A new non-invasive technology for the assessment of left ventricular myocardial work (LVMW) is based on speckle-tracking echocardiography and considers LV pressure. Changes in LVMW are described in patients with different cardiovascular diseases. In patients with chronic heart failure (CHF), LVMW is associated with long-term prognosis and favorable response to cardiac resynchronization therapy.

Purpose
To study echocardiographic parameters, including LVMW, in patients with CHF receiving cardiac contractility modulation therapy.

Methods
The study included 40 patients (31 men and 7 women) aged 60.5 [55.0; 66.0] years with heart failure with reduced ejection fraction (NYHA class II or III) in combination with atrial fibrillation. Before implantation of cardiac contractility modulation (CCM) device and 2, 6 and 12 months after, the patients underwent transthoracic echocardiography with an assessment of the main structural and functional parameters. Also, initially and after 12 months of CCM therapy, an assessment of global longitudinal strain (GLS) and LVMW was performed (global work index (GWI), global constructive work (GCW), global wasted work, global work efficiency (GWE)).

Results
Initially, the patients included in the study had enlarged left heart chambers and decreased left ventricular ejection fraction (LVEF). CCM therapy was accompanied by significant increase in LVEF from 30.0 [26.5; 37.0]% before device implantation up to 34.4 [27.0; 40.0]% (p=0.016) after 2 months and up to 38.0 [30.5; 42.0]% (p&lt;0.01) after 6 months of treatment. One year after device implantation, a significant increase in LVEF was maintained as compared with initial data (39 [31; 45]%, p&lt;0.01). We also analyzed the dynamics of echocardiographic parameters depending on etiology of CHF (ischemic and non-ischemic). As in general group of patients regardless of CHF etiology there was a significant increase in LVEF, that reached maximum values after 12 months of therapy (36 [30; 42]% in group with ischemic etiology, p&lt;0.01 and 37 [30; 45]% in group with non-ischemic etiology, p&lt;0.01). The assessment of GLS before and 12 months after device implantation revealed no significant dynamics (−7 [−9; −4]% and −8 [−9; −5]%, p=0.93). However, we observed significant changes in LVMW: an increase in GWI from 429 [332; 744] to 635 [401; 815] mm Hg% (p=0.01) and GWE (from 73 [68; 79] to 74 [70; 87] %, p=0.02) due to an increase in GCW (from 791 [530; 1031] to 836 [708; 1109] mm Hg%, p=0.03).

Conclusions
A significant increase in LVEF, GWI and GWE in patients with CHF (NYHA class II or III) receiving CCM therapy indicates an improvement in LV systolic function and the effectiveness of CCM therapy. The modern echocardiographic technologies open great opportunities for detailed assessment of the effectiveness of treatment of patients with CHF, including the use of CCM devices.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of Russian Federation