Prognostic value of the ECG
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* Masis Perk

Although the first diagnosis of acute myocardial infarction by electrocardiogram (ECG) dates back to 1920, its prognostic value has enjoyed little attention in the era of “time is muscle.” Instead, various time-based parameters and arithmetical formulas have dominated in both research and practice.

In our region in 2006, we started to organize “eye training” courses to help frontline acute cardiac care providers recognize early or subtle ECG changes in ST-segment elevation myocardial infarction (STEMI). This experience quickly led us to conclude that the initial ECG in STEMI actually had a higher potential to provide prognostic information than time-based parameters. Using a combination of 3 parameters (degree of ST elevation, preservation or degree of loss of R wave amplitude, and presence or absence of pathological Q waves), we can assess the status of myocardial injury, depolarization and permanent damage more objectively. Moreover, ECG does not rely on patient’s recall, is widely available, inexpensive and easily repeatable.

Siha and coauthors show the long-term prognostic value of Q waves.1 Using serial ECG follow-up in our course material, we appreciated the value of a combination of 3 ECG parameters regarding timing and mode of therapy in acute STEMI. The message is “If time is myocardium, ECG must be the clock,” which is equally applicable to urban and rural settings.

## Reference

1.  Siha H, Das D, Fu Y, et al. Baseline Q waves as a prognostic modulator in patients with ST-segment elevation: insights from the PLATO trial. CMAJ 2012;184:1135–42.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMToiMTg0LzEwLzExMzUiO3M6NDoiYXRvbSI7czoyNDoiL2NtYWovMTg0LzEzLzE0OTkuMi5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=)