Periodic repolarization dynamics in patients undergoing primary PCI for acute myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Medical University of Innsbruck. Background and aims Periodic Repolarization Dynamics (PRD) is a novel ECG-based risk marker which quantifies sympathetic-activity associated oscillation of repolarization in the low frequency range. [1] Previous studies demonstrated that increased PRD is a strong and independent predictor of mortality in ischemic and non-ischemic cardiomyopathy being closely linked to malignant arrhythmias and sudden death. [2] [3] PRD could also be a useful marker in the setting of acute myocardial ischemia. We therefore aimed to investigate PRD in acute myocardial infarction (MI) and the effects of primary PCI on PRD. Methods Consecutive patients aged ≥ 18 years presenting with acute ST-elevation MI were included. In all patients, a high-resolution (1000Hz) 24-hour ECG recording in Frank leads configuration was started at hospital admission. PRD was assessed for the period before primary PCI and for 24 successive 1-hour periods thereafter according to previously established procedures. [1] Time of PCI was defined as wire crossing. Results Between January and April 2022, a total of 23 patients were enrolled. Median age was 63 (IQR 56 - 70) years, 6 (26 %) patients were female. Average length of the pre PCI segment was 60 (IQR 40 – 78) minutes. Coronary blood flow prior to PCI was TIMI 0 in 10 patients and TIMI 1 in 13 patients. Primary PCI was successful with an achieved TIMI 3 flow in all patients. PRD before primary PCI was increased at 7.8 (IQR 6.4 - 10.5) deg². Within the first six hours after recanalization PRD decreased to 4.1 (IQR 2.8 - 6.2) deg² (p = 0.004 for difference). No significant change of PRD was observed between 6 h and 24 h after PCI (p = 0.652 for difference). Conclusion In patients with acute STEMI, PRD is significantly increased. Revascularization by primary PCI results in a decrease in PRD within the first 6 hours. Our results suggest that arrhythmic risk is increased within the first 6 hours after primary PCI.