Related Experiment Videos
Myocardial infarct extension: incidence and relationship to survival
Abstract:
Myocardial infarct extension, defined as reelevation or reappearance of creatine phosphokinase-MB (CK-MB) 48 hours after the onset of symptoms, was evaluated prospectively in 56 consecutive patients with acute myocardial infarction. Myocardial infarct extension occurred in eight patients (14%). The sensitivity, specificity and predictive accuracy in the diagnosis of myocardial infarct extension were 63%, 85% and 42%, respectively, for recurrent chest pain requiring morphine; 50%, 65% and 19% for recurrent ST-segment elevation on routine 12-lead ECGs; and 88%, 63% and 28% for reelevation of total CK. Three of the eight episodes of extension were clinically silent. Four of eight patients (50%) with extension died, compared with one of 46 patients (2%) without extension (p = 0.0009). CK-MB persisted for 72 hours or longer in 16 patients and identified seven of eight patients who subsequently had infarct extension. We conclude that myocardial infarct extension is an infrequent complication of acute myocardial infarction and is associated with a very high mortality rate. Persistence of CK-MB for 72 hours or more identifies a subgroup of patients at high risk for subsequent infarct extension and death.
Insights
Myocardial infarct extension, a rare complication of heart attack, occurred in 14% of patients. Persistent creatine phosphokinase-MB (CK-MB) levels over 72 hours indicate a high risk for extension and death.
Area of Science:
- Cardiology
- Biomarkers
- Clinical Medicine
Background:
- Myocardial infarct extension, defined by creatine phosphokinase-MB (CK-MB) elevation, is a significant complication of acute myocardial infarction.
- Early identification of infarct extension is crucial for patient management and prognosis.
Purpose of the Study:
- To prospectively evaluate the incidence and diagnostic accuracy of various indicators for myocardial infarct extension.
- To assess the prognostic implications of infarct extension, particularly mortality rates.
Main Methods:
- Prospective evaluation of 56 consecutive patients with acute myocardial infarction.
- Assessed recurrent chest pain, ST-segment elevation on ECG, and reelevation of total creatine kinase (CK) for diagnosing infarct extension.
- Monitored CK-MB levels for persistence beyond 72 hours.
Main Results:
- Myocardial infarct extension occurred in 14% of patients.
- Persistent CK-MB for ≥72 hours showed 88% sensitivity and 63% specificity for infarct extension.
- Patients with infarct extension had a significantly higher mortality rate (50% vs. 2%).
Conclusions:
- Myocardial infarct extension is an infrequent but highly fatal complication.
- Persistent CK-MB for 72 hours or longer is a valuable marker for identifying high-risk patients.
- Early detection and management of infarct extension are critical for improving outcomes.