ABSTRACT: BACKGROUND:To evaluate subtle and early premature ventricular complex (PVC)-induced ventricular impairment in patients with frequent PVCs and without structural heart disease by real-time 3-dimensional (3D) speckle tracking echocardiography (RT3D-STE). HYPOTHESIS:Patients with frequent premature ventricular complexes with normal left ventricular ejection fraction have subtle left ventricular dysfunction. METHODS:Forty patients (22 male) with a single source of frequent PVCs and 40 healthy controls (24 male) underwent assessment by conventional 2-dimensional (2D) echocardiography and RT3D-STE. Left ventricular ejection fraction (LVEF), and global longitudinal, circumferential, radial, and area strain (GLS, GCS, GRS, and GAS, respectively) and individual segment strain were calculated using off-line analysis software and compared between the 2 groups. RESULTS:There were no significant differences in baseline clinical or 2D echocardiographic variables including LVEF between groups. However, all RT3D-STE assessed variables, including GLS, GCS, GRS, GAS, and individual segment strain, were significantly lower (P < 0.05) in the PVC group than the control group, and showed strong correlations, most prominently GCS (r = -0.84, P = 0.020), with LV function as assessed by LVEF. 3D-STE measurements showed good intraobserver, interobserver, and test-retest agreement. CONCLUSIONS:In patients with frequent PVCs and normal LVEF, 3D -STE revealed lower global and regional strain values than in healthy controls. RT3D-STE is a novel, feasible and reproducible method to assess cardiac function and appears suitable to detect subtle left ventricular dysfunction.