Related Experiment Videos
Value and limitations of electrocardiogram in diagnosis of slight and subacute coronary attacks
Insights
Initial electrocardiograms (ECG) often fail to diagnose acute myocardial infarction, even when symptoms are present. This highlights the need for further diagnostic evaluation beyond the initial ECG in suspected coronary events.
Area of Science:
- Cardiology
- Diagnostic Imaging
Background:
- Electrocardiography (ECG) is a primary tool for diagnosing acute myocardial infarction (MI).
- Subtle or sub-acute coronary events may present diagnostic challenges with initial ECG findings.
Purpose of the Study:
- To evaluate the diagnostic accuracy of initial electrocardiograms (ECG) in patients with suspected acute or sub-acute coronary events.
- To compare initial ECG findings with final diagnoses in a cohort of patients presenting with suspected coronary attacks.
Main Methods:
- Retrospective analysis of 211 consecutive suspected coronary events in 206 patients.
- Comparison of initial ECG tracings with final clinical diagnoses.
- Classification of ECG abnormalities using the Minnesota Code.
Main Results:
- Acute myocardial infarction was diagnosed in 36% of episodes (77/211).
- Initial ECG was diagnostic in only 25% (19/77) of confirmed MI cases.
- Abnormal but non-diagnostic ECGs were seen in 50% (39/77) of MI cases, with 25% (19/77) showing no Minnesota Code abnormality.
- In cases where MI was excluded (29%, 61/211), 38% (23/61) had grossly abnormal ECGs, and 25% (15/61) showed minor abnormalities.
Conclusions:
- Initial ECGs have limited sensitivity for diagnosing acute myocardial infarction, particularly in subtle or sub-acute cases.
- A significant proportion of patients with confirmed MI show non-diagnostic or even normal initial ECGs.
- Alternative diagnostic methods are crucial when initial ECG findings are inconclusive or discordant with clinical suspicion.
Abstract:
The electrocardiogram recorded at the initial consultation was compared with the final diagnosis in 211 consecutive suspected slight or sub-acute coronary attacks in 206 patients.In 77 (36%) of the 211 episodes, acute (or subacute) myocardial infarction was finally diagnosed. The initial E.C.G. showed a diagnostic pattern in only 19 (25%) of these 77 episodes; in 39 (50%) it was abnormal but not diagnostic of recent infarction; while in 19 (25%) the E.C.G. showed no abnormality classified under the Minnesota Code, though in 16 of these there were definite minor changes.In 61 (29%) of the 211 episodes acute myocardial infarction was excluded and an alternative diagnosis was made. The E.C.G. was strictly normal in only 23 (38%) of these 61 episodes; in 15 (25%) it showed minor abnormalities, and in 23 (38%) it was grossly abnormal.