Study of left ventricular torsional mechanics in patients with premature ventricular complexes from right ventricular outflow tract

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Objective To assess alternations in left ventricular(LV) torsion parameters in healthy subjects and patients with premature ventricular complexes (PVCs) from the right ventricular outflow tract (RVOT). Methods Thirty patients with PVCs from RVOT and 31 healthy subjects were included. Two-dimensional speckle tracking imaging(2D-STI) was applied to evaluate LV torsion parameters, including LV rotational degrees in basal and apical levels respectively, LV total torsional degrees, and time to peak rotational and torsional degrees. All values of patients with PVCs were recorded during both sinus beats (PVC-S) and premature ventricular beats (PVC-V). Results No significant difference was observed in left ventricular ejection fraction(LVEF) between PVC-S group and control subjects(P>0.05), while LV rotational degrees in apical levels[(8.47±3.54)° vs (9.50±3.21)°, P=0.042] and LV total torsional degrees [(11.25±6.31)° vs (14.00±4.07)°, P=0.046] were significantly reduced in PVC-S group. In addition to the reduction of LV rotational degrees in apical levels[(3.93±7.23)° vs (9.50±3.21)°, P=0.000] and LV total torsional degrees[ (4.35±9.62)° vs (14.00±4.07)°, P=0.000], lower apical levels [(-0.57±4.44)° vs (-5.26±3.84)°, P=0.000] and advanced LV rotational degrees [(40.5±18.6)% vs (48.0±9.1)%, P=0.05] in basal levels were observed in PVC-V group in comparison with the control subjects. Compared with the PVC-S group, PVC-V group showed lower LV rotational degrees in basal levels [(-0.57±4.44)° vs (-4.57±4.57)°, P=0.000] and advanced time to peak rotational degrees [(40.5±18.6)% vs (48.1±12.6)%, P=0.018], as well as advanced time to peak and lower LV total torsional degrees [(39.3±15.4)% vs (46.7±13.8)%, P=0.007; (4.35±9.62)° vs (11.25±6.31)°, P=0.001]. Conclusions As to RVOT-PVC patients, LV myocardial torsional motion has changed in PVC-S mainly manifested as a decrease of rotation degrees in apical levels even if the LVEF is still in the normal range. During PVC-V the rotation and twist degree is further reduced, and the time sequence altered, accompanied with significantly decreased LVEF. Key words: Echocardiography; Ventricular premature complexes; Ventricular function, left; Torsion