# Impact of Fitness on Cardiac Torsion and Wall Mechanics in Ischemic Heart Disease Study (FIT-TWIST)

## TL;DR

A 36-session cardiac rehabilitation program improved heart mechanics in ischemic heart disease patients compared to those who did not participate.

## Contribution

This study demonstrates that cardiac rehabilitation enhances left ventricular strain and torsion in ischemic heart disease patients.

## Key findings

- Cardiac rehab improved left ventricular global longitudinal strain (GLS) in IHD patients.
- CR participants had better left ventricular twist and right ventricular free wall strain compared to non-participants.
- Non-participants showed deterioration in right ventricular free wall strain over time.

## Abstract

Background: Cardiac rehabilitation (CR) and mechanics are individually associated with cardiovascular outcomes in ischemic heart disease (IHD); however, their interaction remains less defined. We hypothesized that a 36-session CR program improves cardiac strain and torsional mechanics in IHD patients. Methods: Ninety IHD patients on guideline-directed medical therapy with complete revascularization were prospectively enrolled, of which 27 electively completed a 36-session standardized exercise CR program. Speckle-tracking echocardiography was utilized to assess left ventricular (LV) global longitudinal strain (GLS) and peak twist, and right ventricular free wall strain (RVFWS) at baseline and after program completion. Participants were propensity-scoring matched 1:1 with 27 patients who declined participation (No-CR). Results: Clinical characteristics were similar between groups (mean age: 63 ± 10 years, 82% male, 31% three-vessel coronary artery disease). When compared with baseline, the CR group experienced a significant improvement in LV GLS (−14.9 ± 2.9 vs. −16.2 ± 3.1%, p = 0.003), with a numerical but non-significant increase in peak LV twist (14.4 ± 7.4 vs. 16.8 ± 5.3°, p = 0.162). The No-CR group showed significant deterioration in RVFWS (−22.9 ± 4.6% vs. −19.3 ± 5.4%, p = 0.009), with no other changes including in GLS (−14.8 ± 3.1 vs. −15 ± 3.3%, p = 0.831). Follow-up comparisons between CR versus No-CR revealed significantly greater peak LV twist (16.8 ± 5.3 vs. 12.1 ± 4.2°, p = 0.001) and a healthier RVFWS (−22.2 ± 4.5 vs. −19.3 ± 5.4, p = 0.044) in CR participants. Conclusions: CR in patients with IHD improved LV GLS and, compared with No-CR, conferred better LV twist and RVFWS.