Abstract：Objective To clarify the electrocardiographic characteristics of outflow tract ventricular premature ventricular contraction(OT-PVC) with ventricular tachycardia(VT) by comparing the electrocardiographic parameters between OT-PVC with VT and OT-PVC without VT. Methods Thirty-three patients with sustained OT-VT which had monomorphic QRS morphology(VT group) and 37 patients with frequent OT-PVC(PVC group) were enrolled. The prematurity index(PI), coupling interval(CI), interval from the peak to the end of the T wave(Tp-Te), duration of QRS complex during sinus rhythm, sinus cycle length, CI index, QT interval, QTc and incidence of fragmented QRS complexes were compared between the two groups Results No difference existed in baseline characteristics between the two groups. The duration of QRS complex[(101.33±19.46)ms vs.(89.40±14.02)ms］, Tp-Te[(141.1±78.55)ms vs.(76.60±23.29)ms］, CI index(0.71±0.17 vs.0.62±0.10) in the VT group were significantly prolonged versus PVC group(P<0.05)PI(1.34±0.19 vs.1.64±0.60, P<0.05) in the VT group was shorter than PVC group Logistic regression analysis revealed that CI index and Tp-Te were the determinants of transition from OT-PVC to monomorphic OT-VT(odd ratio=270.03 and 1.025, respectively) A CI index value greater than 0.74 predicted sustained VT with a sensitivety of 45-5% and specicity of 89-2%, and a Tp-Te greater than 94 ms predicted sustained VT with a sensitivety of 57.6% and specicity of 89.2%. ConclusionPI and Tp-Te may be the predictors of the OT-PVC with monomorphic OT-VT, and OT-PVC with longer PI and Tp-Te may have a higher possibility to transform to OT-VT.
2019, Vol. 28 
