The time course of ECG-parameters has no quantitative significance in the thrombolytic era

Spatial ST-vector magnitudes, |ST_40-80|, were measured every 3 min for at least 3 h after admission, and at wider intervals for 3 days. Likewise, the magnitudes of the difference vector |ΔQRS| between the vectorcardiogram (VCG) on admission and a subsequent VCG were determined. The VCG was synthesized from eight electrocardiogram (ECG) leads through linear transformation. The study included 18 patients, only three of whom did not undergo interventions. |ST_40-80| was always maximal on admission and declined to a stable level in about 4.5. Over the same time span |ΔQRS| showed an inconspicuous rise. Correlation of these parameters with infarct size determined by 76 h cumulative serum a-hydroxy-butyrate dehydrogenase activity was poor. Evidently, important ECG charges have already taken place before admission, but even allowing for this, little quantitative relation between VCG parameters and infarct size was apparent