Prevalence of secondary ST-T wave electrocardiographic abnormalities confounding the diagnosis of acute myocardial ischemia in patients presenting to the emergency department with a chief complaint of chest pain

Abstract

Chest pain in patients presenting to the emergency department (ED) has a plethora of etiologies and electrocardiographic (ECG) manifestations. Admission to the hospital from the ED with chest pain will likely place the patient on a telemetry monitored unit for continued cardiac monitoring, specifically monitoring the ST-segment that can detect ischemia. The current guideline for in-hospital cardiac monitoring lists a few exclusions to ST-segment ischemia monitoring such as bundle-branch blocks, ventricular rhythms, and coarse atrial fibrillation or flutter (Drew et al., 2004). These conditions alter the ST-segment for reasons unrelated to acute myocardial ischemia, triggering ST-segment monitor alarms that can lead to alarm fatigue, misdiagnosis, or inappropriate treatment. The purpose of this study is to determine the prevalence and clinical significance of these non-ischemic ECG abnormalities that alter the ST-segment and affect the healthcare professionals’ accurate assessment of myocardial ischemia in patients that present to the ED with a chief complaint of chest pain. This study includes a secondary analysis of the ongoing Electrocardiographic Methods for Prompt Identification of Coronary Events (EMPIRE) study data set, which aims to quantify ischemia-induced repolarization dispersion for early non-ST elevation myocardial infarction detection. The parent study has created a database of patients who arrive via ambulance to the ED with a chief complaint of chest pain (Al-Zaiti, Martin-Gill, Sejdic, Alrawashdeh, & Callaway, 2015). In this secondary analysis, the demographic, clinical, and ECG data from 750 consecutively enrolled patients were assessed for acute coronary syndrome risk factors and ECG abnormalities, including secondary repolarization changes that interfere with ST-segment monitoring. 75% of patients were admitted and 16% of patients overall had confounders for ST-segment monitoring. Significant relationships between ST-segment monitoring confounders and important clinical variables such as age, coronary artery disease risk factors, and length of stay were found. Determination of the prevalence of ECG abnormalities that affect the ST-segment would provide valuable information on the clinical utility of ST-segment monitoring in chest-pain populations