Oakland, CA - Chronic ST elevation caused by early repolarization is especially prevalent in young black men engaging in vigorous exercise but has an essentially benign prognosis, according to a study published in the August 15, 2003 issue of the American Journal of Medicine.1

"Unnecessary or incorrect diagnostic tests, therapeutic decisions, including administration of thrombolytic drugs, and hospital admissions might result from misinterpretation of this essentially benign condition," the researchers, headed by Dr Arthur Klatsky (Kaiser Permanente Medical Center, Oakland, CA) point out, referring to the fact that early repolarization resembles the ECG of acute MI, pericarditis, or ventricular aneurysm. "A dilemma might occur when a patient with ST variant presents with chest pain and no prior available electrocardiogram," according to Klatsky et al. For this study, the researchers assumed that patients with early repolarization ECGs to be at a higher-than-normal risk of being hospitalized for chest pain. To determine characteristics and outcomes in patients presenting with early repolarization, they evaluated ECGs from 73088 patients undergoing health examinations.

Compared with patients with normal ECGs, those presenting with early repolarization were younger, more physically active, more likely to be male and black, and had lower BMI, blood pressure, and cholesterol and glucose levels. The high prevalence of this ST elevation variant in young, athletic black men could be attributed to genetic as well as environmental factors, the authors suggest.

The researchers report no increased risk of hospitalization or death, including fatal and nonfatal cardiovascular conditions, in patients with early repolarization. In fact, these patients showed slightly lower rates for most cardiovascular conditions. "Refuting our prestudy hypothesis, patients with early repolarization were neither more likely to be admitted for chest pain nor to be diagnosed with chest pain as outpatients," they concluded.

However, there is still a chance of misinterpreting ST elevation due to early repolarization as changes due to MI. "The big problem comes when someone is being critically evaluated in an emergency department with symptoms possibly suggesting a cardiac condition such as acute MI or pericarditis, in which ST elevation may also be present," coauthor Dr Rudolph Oehm (Kaiser Permanente Medical Center, Oakland, CA) explained to heartwire.

How to uncover early repolarization

Taking such care in diagnostics must be balanced against delaying justified and life-saving reperfusion therapy.

In an accompanying editorial, Dr Lauren Dowdy (Duke Clinical Research Center, Durham, NC) et al highlight several possible noninvasive and practical approaches to resolve doubts about a diagnosis of serious coronary disease:2

New ECG interpretive algorithms, with a computer system able to identify magnitude and contour of the ST-segment elevation in ST-elevation MI (STEMI), to accurately distinguish STEMI from mimics such as early revascularization.

Serial ECG comparison, ie, improving diagnostic accuracy by comparing previous and current recordings. To expedite previous ECG retrieval, Dowdy and colleagues suggest computerizing ECG information and asking patients to carry a copy of their recent ECG. "The Personal Electronic Health Record is becoming a reality in several countries," they point out.

Myocardial imaging techniques, such as two-dimensional echocardiography, single-photon-emission CT imaging (which predicts the absence of MI), nuclear imaging, or contrast echocardiography.

Acute coronary catheterization in some cases, as an emergency diagnostic procedure.

Proceeding with any therapy without an accurate diagnosis may be fraught with serious complications and dangers.

However, some of these approaches are time-consuming and, therefore, difficult in an emergency situation. "Taking such care in diagnostics must be balanced against delaying justified and life-saving reperfusion therapy," the editorialists write.

Oehm agrees: "In an era when making an immediate diagnosis is so crucial, so as to avoid major infarction damage to the heart with serious complications, a real quandary may be presented. Some of these means are not available at many places, and some are not available with sufficient rapidity to make a timely diagnosis." On the other hand, he cautions that "proceeding with any therapy without an accurate diagnosis may be fraught with serious complications and dangers."