| Background. Early reperfusion therapy to limit infarct size was introduced in the late 1980s. The effect of this advance in cardiac care on the occurrence of arrhythmias in acute coronary syndromes (ACS) is unknown. The purpose of this study was to describe arrhythmias during the first 24 hours of hospital admission and explore predictors and outcomes of arrhythmias in patients with ACS in the post-reperfusion era. Methods. Electrocardiographic (ECG) data from patients with ACS who participated in a larger prospective study evaluating myocardial ischemia in an urban medical center were analyzed. Research nurses applied radiolucent electrodes and attached a Holter recorder for continuous 12-lead ECG monitoring upon emergency department (ED) admission. ECG data were downloaded for computer- assisted analysis and manual evaluation of each recording confirmed the type of arrhythmias. Arrhythmia occurrence rates were compared with rates from studies before early reperfusion became the norm. Predictors and outcomes of clinically significant arrhythmias were analyzed using multivariate techniques. Results. The sample of 278 patients (57% male, 51% white, mean age 66+/-14 years) included 35% with acute myocardial infarction (AMI) and 65% with unstable angina. Sustained ventricular tachycardia (VT) and ventricular fibrillation happened less frequently than in the pre-reperfusion era (1% vs. 21% and 0.4% vs. 11%; p<.001 for both). The occurrence of premature ventricular contractions (PVCs) (89% vs. 58%; p<.001) was higher in the post-reperfusion era. Non-sustained VT (2-14 consecutive PVC; 51%) independently predicted a cardiovascular ED readmission within 1 year and PVCs >50/ hour (22%) independently predicted a longer length of stay. Conclusions. Patients have fewer life-threatening arrhythmias today, but experience frequent PVCs and non-sustained VT. These arrhythmias may be markers for increased severity of heart disease, but not independent predictors of adverse outcomes. |
