Abstract
Background: Arrhythmias are considered one of the major causes of death in ST el‐ evation myocardial infarction (STEMI), particularly in the early in‐hospital phase. Pre‐ infarction angina (PIA) has been suggested to have a protective role.
Objectives: To study the difference in acute electrocardiographic findings between STEMI patients with and without PIA and to assess the in‐hospital arrhythmias in both groups.
Material and Methods: We prospectively enrolled 238 consecutive patients with STEMI. Patients were divided into two groups: those with or without PIA. ECG data recorded and analyzed included ST‐segment resolution (STR) at 90 min, corrected QT interval (QTc) and dispersion (QTD), T‐peak‐to‐T‐end interval (Tp‐Te), and dispersion and Tp‐Te/QT ratio. In‐hospital ventricular arrhythmias encountered in both groups were recorded. Predictors of in‐hospital arrhythmias were assessed among different clinical and electrocardiographic parameters.
Results: Of the 238 patients included, 42 (17%) had PIA and 196 (83%) had no PIA. Patients with PIA had higher rates of STR (p < 0.0001), while patients with no PIA had higher values of QTc (p = 0.006), QTD (p = 0.001), Tp‐Te interval (p = 0.001), Tp‐Te dispersion (p < 0.0001), and Tp‐Te/QT ratio (p = 0.01) compared to those with angina preceding their incident infarction (PIA). This was reflected into significantly higher rates of in‐hospital arrhythmias among patients with no PIA (20% vs. 7%, p = 0.04). Furthermore, longer Tp‐Te interval and higher Tp‐Te/QT ratio independently pre‐ dicted in‐hospital ventricular arrhythmias.
Conclusion: Pre‐infarction angina patients had better electrocardiographic measures of repolarization dispersion and encountered significantly less arrhythmic events compared to patients who did not experience PIA.