Left ventricular torsional mechanics after left ventricular reconstruction surgery for ischemic cardiomyopathy

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 134; no. 4; pp. 888 - 896
• Main Authors: Setser, Randolph M., DSc, Smedira, Nicholas G., MD, Lieber, Michael L., MS, Sabo, Eric D, White, Richard D., MD
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Mosby, Inc 01.10.2007; AATS/WTSA; Elsevier
• Subjects: Adult; Biological and medical sciences; Cardiology. Vascular system; Cardiomyopathy, Dilated - physiopathology; Cardiomyopathy, Dilated - surgery; Cardiothoracic Surgery; Case-Control Studies; Female; Heart; Heart Ventricles - physiopathology; Heart Ventricles - surgery; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Medical sciences; Middle Aged; Myocarditis. Cardiomyopathies; Rotation; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Torsion Abnormality; Treatment Outcome; Ventricular Dysfunction, Left - physiopathology; Ventricular Dysfunction, Left - surgery; 22; 23; magnetic resonance imaging; ejection fraction; MRI; MVR; LVR; LV; EDV; left ventricular reconstruction; echo time; end-diastolic volume; coronary artery bypass grafting; EF; SV; repetition time; FOV; field of view; stroke volume; TE; ICM; ischemic cardiomyopathy; mitral valve replacement/repair; left ventricle(ular); CABG; TR; Heart; Treatment; Ischemia; Cardiomyopathy; Heart disease; Surgery; Mechanics; Cardiovascular disease; Anatomical reconstruction; Thorax; Myocardial disease; Left ventricle
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/j.jtcvs.2007.05.060

Objectives Surgical left ventricular reconstruction improves symptoms and potentially prognosis in patients with ischemic cardiomyopathy; however, the effects of reconstruction on myocardial mechanics are not well defined. Therefore, we have computed left ventricular rotation and torsion in patients undergoing left ventricular reconstruction to determine its effects on these quantitative measures of myocardial mechanics. Methods Magnetic resonance imaging with tissue grid-tagging was performed in 26 patients (19 male/7 female, 62 ± 11 years) (mean ± standard deviation) before (23 ± 29 days) and after (231 ± 106 days) left ventricular reconstruction, as well as in 7 healthy volunteers (5 male/2 female, 34 ± 7 years). Left ventricular rotation was computed at basal and apical short-axis levels; torsion was defined as the difference between apical and basal rotation. Results Before left ventricular reconstruction, maximal apical rotation was significantly impaired relative to that of healthy volunteers ( P = .001), although maximal basal rotation was preserved ( P = .84). After reconstruction, maximal torsion did not change significantly: torsion was 6° ± 3° both before and after reconstruction ( P = .84). However, the rate of early diastolic untwist improved significantly after reconstruction (−18°/s ± 13°/s vs −23°/s ± 14°/s; P = .04). Furthermore, patients with relatively worse torsion before reconstruction demonstrated more improved function after reconstruction; patients with torsion of less than 6° (n = 12) showed greater improvement in ejection fraction (15% vs 6%; P = .005), torsion (1° vs −1°; P = .01), and diastolic untwist (−9°/s vs −25°/s; P < .001) than did patients with torsion of 6° or more (n = 14). Conclusions Torsional mechanics were severely impaired by ischemic cardiomyopathy. On average, left ventricular reconstruction did not affect systolic torsion generation significantly; however, patients with relatively worse torsion did show improvement. Furthermore, the rate of untwist improved after surgery, suggesting that diastolic function was improved.