Relationship of ST-segment elevation to eventual QRS loss in acute anterior wall myocardial infarction.

The position of electrocardiographic ST-segment elevation in acute myocardial infarction (MI) is related to the region of infarction, but the relationship between the initial ST-segment elevation and the eventual loss of QRS voltage remains uncertain. The authors examined body surface map data in 76 patients with acute anterior wall MI to clarify this relationship. The patients had no evidence of previous MI, no subsequent MI, and did not receive thrombolytic therapy or other acute interventions. Maps were recorded on admission to the hospital, every 24 hours during the hospital stay, and again at follow-up examinations 6-48 months after the index MI. The region of ST-segment elevation on the initial body surface map was compared to the region of developed voltage loss in the QRS complex as measured by the integral 0-30, 0-40, 0-80, and 30-80 ms body surface maps subsequently recorded 24 hours, 48 hours, and over 6 months after the initial body surface map. There was a relationship between the position of the ST-segment elevation and the loss of the QRS segment voltages, which was pronounced early after acute MI and diminished months after the MI. The region of ST-segment elevation in the initial body surface map predicts the QRS loss. In the integral QRS0-30 map versus the initial ST-segment map the mean correlation coefficient was -0.54 +/- 0.33 with a median value of -0.67. The integral QRS0-40 map and ST-segment map had a mean correlation coefficient of 0.60 +/- 0.29 and median of 0.66. The mean correlation coefficient is less for the integral QRS0-80 map and nonexistent in the integral QRS30-80 map. This method may be useful for monitoring acute interventions in acute MI.