Clinical Significance of Conditions Presenting with ECG Changes Mimicking Acute Myocardial Infarction

The electrocardiogram (ECG) is the primary tool in the diagnosis of acute myocardial infarction (AMI). However, other clinical conditions, both cardiac and noncardiac originated pathologies, may result in ECG tracing of AMI. This may lead to an incorrect diagnosis, exposing the patients to unnecessary tests and potentially harmful therapeutic procedures. The aim of this report is to increase the still insufficient awareness of clinicians from multiple disciplines, regarding the different clinical syndromes, both cardiac and noncardiac, associated with ECG abnormalities mimicking AMI, to avoid unjustified thrombolytic therapy or intervention procedures. During a 9-year period, the data from six patients (five females, one male; mean age, 50 years [range, 18 to 78 years]) who were admitted to cardiac care unit (CCU) with transient ECG changes resembling AMI were recorded retrospectively. During this 9-year period, 5,400 patients were hospitalized in CCU: 1,350 patients were diagnosed as ST-elevation myocardial infarction (STEMI) and 4,050 patients were diagnosed as non-ST-elevation myocardial infarction (NSTEMI). Only two out of six patients had chest pain with ECG changes criteria suspicious of AMI. STEMI was suspected in four out of six patients. All patients, but one, had normal left ventricular (LV) function. One patient had transient LV dysfunction. All patients, but one, with perimyocarditis, had normal serum cardiac markers. In four out of six patients, who underwent coronary arteries imaging during hospitalization (by angiography or by CT scan), normal coronary arteries were documented. Two patients who underwent ambulatory cardiac CT scan imaging after being discharged from hospital documented patent coronary arteries (case no. 3), or some insignificant irregularities (case no. 4). The discharge diagnoses from CCU were as follows: postictal syndrome, pericarditis, hypothermia, stress-induced ("tako-tsubo") cardiomyopathy, anaphylactic reaction, and status of postchemotherapy. All patients experienced full recovery with normal ECG tracing. During the 5-year follow-up, all patients were alive, and cardiac morbidity was not reported. We conclude that both cardiac and noncardiac clinical syndromes may mimic AMI. Comprehensive clinical examination and profound medical history are crucial for making the correct diagnosis in conditions with ECG changes mimicking AMI.