Elucidating the mechanisms underlying left ventricular function recovery in patients with ischemic heart failure undergoing surgical remodeling: A 3-dimensional ultrasound analysis

Objective: The study objective was to elucidate the mechanisms of left ventricle functional recovery in terms of endocardial contractility and synchronicity after surgical ventricular reconstruction.Methods: Real-time 3-dimensional transthoracic echocardiography was performed on 20 patients with anterior left ventricle remodeling and ischemic heart failure before surgical ventricular reconstruction and at 6-month follow-up, and on 15 healthy controls matched by age and body surface area. Real-time 3-dimensional transthoracic echocardiography datasets were analyzed through TomTec software (4D LV-Analysis; TomTec Imaging Systems GmbH, Unterschleissheim, Germany): Left ventricle volumes, ejection fraction, and global longitudinal strain were computed; the time-dependent endocardial surface yielded by 3-dimensional speckle-tracking echocardiography was postprocessed through in-house software to quantify local systolic minimum principal strain as a measure of fiber shortening and mechanical dispersion as a measure of fiber synchronicity.Results: Compared with controls, patients with heart failure before surgical ven-tricular reconstruction showed lower ejection fraction (P <.0001) and significantly impaired mechanical dispersion (P < .0001) and minimum principal strain (P<.0001); the latter worsened progressively from left ventricle base to apex. After surgical ventricular reconstruction, global longitudinal strain improved from -6.7% to -11.3% (P < .0001); mechanical dispersion decreased in every left ventricle region (P < .017) and mostly in the basal region, where computed me-chanical dispersion values were comparable to physiologic values (P > .046); min-imum principal strain improved mostly in the basal region, changing from -16.6% to -22.3% (P = .0027).Conclusions: At 6-month follow-up, surgical ventricular reconstruction was asso-ciated with significant recovery in global left ventricle function, improved me-chanical dispersion indicating a more synchronous left ventricle contraction, and improved left ventricle fiber shortening mostly in the basal region, suggesting the major role of the remote myocardium in enhancing left ventricle functional recovery. (J Thorac Cardiovasc Surg 2023;165:1418-29)