Background: The incidence of arrhythmic complications in Thai patients with acute coronary syndromes (ACS) has not been previously reported. The present study results will serve as the local database for future studies.

Objective: To evaluate the incidence of arrhythmic complications in ASC in Thai patients and to identify factors that may affect arrhythmia complications in ACS patients.

Material and Method: Data collected from 9,373 patients from the Thai acute coronary syndrome registry (TACSR) were analyzed. This registry includes patients who presented with ACS including ST elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI) and unstable angina (UA), within 14 days from the symptoms onset.

Results: 395 (4.2%) patients with an ACS presented after cardiac arrest. These patients were noted to have significantly higher in-hospital mortality (50.1%). The incidence of serious cardiac arrhythmia complications in the TACSR was 16.6%. Among them, 62.7% were sustained VT/VF, 31.5% had second or third degree AV block, and 5.8% has both VT/VF and AV Block. The incidence of VT was higher in the younger age group, while AV block and arrhythmic death were higher in the older aged patients. Arrhythmias complicating ACS were associated with increased mortality risk. Congestive heart failure (CHF) within the first 48 hours, current use of tobacco and cardiac troponin elevation were associated with significantly higher arrhythmic complications during hospitalization.

Conclusion: Arrhythmias complicating ACS were associated with higher in hospital mortality. CHF within the first 48 hr., current tobacco use and cardiac troponin elevation were associated with significantly higher arrhythmic complications.

Keywords: Acute coronary syndrome, Cardiac arrhythmia, Ventricular tachycardia, AV block