Prognostic significance of abnormal P wave morphology and PR-segment displacement after ST-elevation myocardial infarction.

INTRODUCTION: Atrial infarction is uncommonly diagnosed and data on its significance are limited. Its incidence in ST-elevation myocardial infarction (STEMI) reportedly ranges from 0.7-42%. Certain atrial ECG changes, such as abnormal P wave morphology suggestive of atrial involvement have been associated with 90-day mortality after STEMI. However, whether atrial ECG changes are associated with short (30-day) or long-term (1-year) mortality have not been studied. METHODS: We examined index ECG in 224 consecutive STEMI. Demographics, clinical variables, peak troponin I, ejection fraction, and angiographic data were collected. Atrial ECG patterns were examined and correlated with mortality. RESULTS: Length of stay was longer with abnormal P waves (p=0.008) or PR displacement in any lead (p=0.003). Left main coronary disease was more prevalent with abnormal P wave (p=0.045). Abnormal P wave morphology in any lead was associated with higher 30-day (OR 3.09 (1.35-7.05)) and 1-year mortality (OR 5.33 (2.74-10.36)). PR displacement in any lead was also associated with increased 30-day (OR 2.33 (1.03-5.28)) and 1-year mortality (OR 6.56 (3.34-12.86)). Abnormal P wave, PR depression in II, III and AVF, and elevation in AVR or AVL were associated with increased 1-year mortality (OR 12.49 (5.2-30.0)) as was PR depression in the precordial leads (OR 21.65 (6.82-68.66)). After adjusting for age, ejection fraction, peak troponin I, and left main disease, PR displacement in any lead was associated with increased 1-year mortality (adjusted OR 6.22 (2.33-18.64)). CONCLUSION: PR segment displacement in any lead, found in 31% of patients with STEMI, independently predicted 1-year mortality.

Utility of the QT interval in predicting outcomes in patients presenting to the emergency department with chest pain.

OBJECTIVES: The aim of this study was to investigate whether prolongation of the heart rate-corrected QT interval (QTc) is an independent risk factor for predicting future acute coronary syndrome (ACS) occurrence or mortality in patients with at least one cardiac risk factor presenting with chest pain to the emergency department (ED). METHODS: This is a single-center, retrospective study of patients presenting with chest pain to the ED of Einstein Medical Center, Philadelphia, between 2011 and 2012. Proportional hazards models were used to calculate hazard ratios (HRs) for occurrence of ACS or death within 1 year. Kaplan-Meier curves were used to determine the time to event for QTc low (< 460 ms) versus QTc high (≥ 460 ms) groups. RESULTS: A total of 595 patients met the inclusion criteria. Older age, hypertension, diabetes mellitus, and hyperlipidemia were more common in the QTc high group. Patients in the QTc high group were more likely to experience subsequent ACS or death (HR 8.12, 95% confidence interval 4.00-16.72), even after adjusting for traditional cardiac risk factors (HR 7.68, 95% confidence interval 3.57-16.61). CONCLUSION: QTc prolongation at ED presentation with chest pain and at least one cardiac risk factor predicts subsequent ACS and death.