Serial ECGs are less accurate than serial CK-MB results for emergency department diagnosis of myocardial infarction

Ann Emerg Med. 1992 Dec;21(12):1445-50. doi: 10.1016/s0196-0644(05)80057-5.


Hypothesis: Serial creatine kinase-MB (CK-MB) levels provide more accurate predictive information regarding myocardial infarction than serial ECGs in emergency department patients with chest discomfort and no ST-segment elevation on the initial ECG.

Design: Prospective, observational study.

Setting: University hospital and university-affiliated Veterans Affairs Medical Center EDs.

Participants: Two hundred sixty-one patients 30 years or older with chest discomfort warranting an ECG and consenting to observation. Exclusions included hemodynamic or rhythm instability and ST-segment elevation of 0.1 mV or more in two or more electrically contiguous leads at presentation.

Measurements: ECGs were obtained at presentation and three to four hours after presentation. Significant serial ECG changes sought on comparison of initial and three- to four-hour ECGs were 0.05 mV or more ST elevation or depression, Q-wave development, or T-wave inversion changes in two or more electrically contiguous leads. CK-MB levels were obtained at presentation and hourly for three hours (positive level, 8 or more ng/mL). Myocardial infarction was determined by record review and was based on independent CK-MB measurements.

Results: Twenty-eight (11%) patients were diagnosed with a myocardial infarction. Thirty-eight (15%) patients had a serial ECG change. Eleven of the myocardial infarction patients (39%) had a serial ECG change compared with 27 (12%) of the non-myocardial infarction patients (P < .001). Sensitivities and specificities of a serial ECG change versus serial CK-MBs for myocardial infarction were 39% versus 68% (sensitivity) and 88% versus 95% (specificity), respectively. Serial CK-MBs were more accurate than a serial ECG change for predicting myocardial infarction (P < .03).

Conclusion: Serial changes in ECGs during a three- to four-hour interval were associated with the diagnosis of myocardial infarction but were infrequent and less accurate than serial CK-MB levels obtained for the same interval.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Chest Pain / diagnosis
  • Creatine Kinase / blood*
  • Electrocardiography*
  • Emergency Service, Hospital
  • Female
  • Humans
  • Isoenzymes
  • Male
  • Middle Aged
  • Myocardial Infarction / diagnosis*
  • Oregon
  • Prospective Studies
  • Sensitivity and Specificity
  • Time Factors


  • Isoenzymes
  • Creatine Kinase