Contribution of the pericardium to left ventricular torsion and regional myocardial function in patients with total absence of the left pericardium

Objective: The relationship between left ventricular (LV) torsional deformation and myocardial function has recently been recognized. However, little is known about whether the pericardium affects this relationship. Our aim was to identify the contribution of the pericardium to LV torsion and regional myocardial function in the clinical setting. Methods: We examined LV torsion in basal and apical LV short-axis views, and regional LV myocardial function, such as longitudinal strain in apical 4-chamber view, and circumferential and radial strains in parasternal LV short-axis views using 2-dimensional speckle-tracking imaging method in 5 patients with congenital total absence of the left pericardium and systolic paradoxical ventricular septal motion on M-mode echocardiogram and in 10 control subjects. Diagnosis of the pericardial defect was based on chest radiograph, computed tomography, jugular phlebogram, and M-mode and 2-dimensional echocardiogram. LV torsion was defined as the net difference in LV rotation in the basal and apical planes. Results: There was no significant difference in LV ejection fraction determined by 2-dimensional echocardiography between the pericardial defect and control groups. LV torsion was markedly decreased in the pericardial defect group compared with the control group. There were no significant differences in longitudinal, radial, and circumferential systolic strains and systolic and early diastolic strain rates in the LV walls and in longitudinal systolic strains and systolic and early diastolic strain rates in the left atrial walls between the two groups. Conclusions: Pericardial defects cause a lack of LV torsion while maintaining LV regional myocardial function in patients with systolic paradoxical ventricular septal motion. Therefore, pericardium plays an important role in LV torsion.