Rotation of the left ventricular apex relative to the base, or left ventricular torsion, is related to myocardial contractility and structure and is a sensitive indicator of cardiac dysfunction. We have quantified left ventricular systolic rotation and torsion in patients with dilated cardiomyopathy before and after partial left ventriculectomy in an attempt to characterize the effects of this surgical procedure on ventricular ejection mechanics.

Magnetic resonance imaging with tissue tagging was performed before partial left ventriculectomy in 24 patients, 9 of whom underwent repeat imaging 3 months after surgery. Left ventricular rotation was quantified in each patient at three short-axis levels: apex, midventricle, and base. Torsion was defined as the difference between basal and apical rotation at any time. Results were subdivided for regional analysis at each level and related to cardiac function (ejection fraction, cardiac index, and velocity of circumferential fiber shortening).

Before surgery, left ventricular rotation was regionally heterogeneous and abnormal in magnitude and pattern, and increased end-systolic torsion was associated with better cardiac function. After surgery, clinical indices of cardiac function showed improvement; however, rotation magnitude was unchanged at the apex and reduced at the base and midventricle, particularly in the anterior wall and septum.

The pattern and magnitude of ventricular rotation were impaired by dilated cardiomyopathy. Left ventricular rotation and torsion were further diminished after partial left ventriculectomy, indicating that improvement in clinical indices of cardiac function was not reflective of an improvement in this measure of myocardial mechanics.