Ventricular premature depolarizations triggered by incremental dose isoproterenol infusion: common electrocardiographic features

Purpose To identify the prevalence of adrenergically mediated ventricular premature depolarizations (VPDs) and characterize their electrocardiographic (ECG) features and specific anatomically determined sites of origin within the ventricles. Methods VPDs occurring during incremental isoproterenol infusion (3 to 20 μg/min) in 108 patients (30 women, mean age 58 ± 10 years) with normal ventricular function and no previous ventricular tachycardia (VT) were identified. VPDs were grouped to a probable anatomic region of origin based on 12-lead ECG. Results The 235 VPD morphologies (median 2 per patient, range 1–13) were observed in 85/108 (79%) patients. The most frequent regions of origin were: peri-mitral annulus 17%, left-Purkinje network 14%, right ventricle (RV) outflow tract 14%, apical RV free wall 11% and peri-tricuspid annulus 10%. Only 39 (17%) VPDs were not easily classified. Conclusion Adrenergically mediated VPDs are frequent in patients without structural heart disease or VT and tend to originate from a few anatomic sites.