Electrocardiographic parameters effectively predict ventricular tachycardia/fibrillation in acute phase and abnormal cardiac function in chronic phase of ST-segment elevation myocardial infarction.

BACKGROUND: Abnormal cardiac repolarization is closely associated with ventricular tachycardia/ventricular fibrillation (VT/VF). Myocardial ischemia and infarction aggravate cardiac repolarization dispersion, and VT/VF could be lethal in the early stage of ST-segment elevation myocardial infarction (STEMI). Unfortunately, VT/VF cannot be effectively predicted in current clinical practice. The present study aimed to assess electrocardiographic parameters of the sinus rhythmic complex in relation to cardiac repolarization, e.g., QT interval and T-peak to T-end interval (TpTe), to independently predict VT/VF in acute STEMI. Additionally, we hypothesized that QT and TpTe of PVC would be also valuable to predict VT/VF in STEMI.

METHODS AND RESULTS: A total of 198 cases diagnosed as STEMI with PVC on admission by electrography were included. During hospitalization, VT/VF values were recorded. Logistic analysis was performed between patients with and without VT/VF to validate independent electrocardiographic predictors. QTcPVC interval > 520 ms (OR = 3.2; P = 0.027), TpTe interval > 100 ms (OR = 3.1; P = 0.04), TpTePVC  > 101 ms (OR = 3.6; P = 0.029), TpTe/QT > 0.258 (OR = 5.7; P = 0.003), and TpTe/QTPVC  > 0.253 (OR = 3; P = 0.048). However, QRS duration, QTc interval, coupling interval, and QRSPVC duration did not predict VT/VF. Besides, QRSPVC duration >140 ms (OR = 2.6; P = 0.001) independently predicted LVEF decrease after 1 year or more.

CONCLUSIONS: QTcPVC interval, TpTe interval, TpTePVC interval, TpTe/QT ratio, and TpTe/QTPVC ratio are risk factors for ECG independent from other confounding factors in predicting VT/VF in the acute phase of STEMI. In addition, PVC characteristics as risk factors for VT/VF in acute phase and LVEF decrease in chronic phase were firstly reported.