Effect of verapamil on ST-segment elevation evaluated by the orthogonal leads of the Frank vector system in patients with acute myocardial infarction.

The effect of i.v. verapamil (0.1 mg/kg) on myocardial ischemic injury was evaluated using the orthogonal leads of the Frank system in 10 selected patients with acute myocardial infarction admitted to the C.C.U. within 8 h from the onset of symptoms. The ST-vector magnitude (STVM) which remained stable over a 2-h control period was progressively and significantly reduced after verapamil administration (-21.1 +/- 5.3%, P < 0.02, 15 min after the injection; -36.5 +/- 6.8%, P < 0.01, after 120 min). Verapamil significantly lowered systemic blood pressure immediately after injection (from a mean value of 134 +/- 3/83 +/- 2 mmHg to 121 +/- 3/76 +/- 2 mmHg); the reduction of systolic blood pressure was effectively maintained through the whole experimental period, while heart rate and the product "heart rate x systolic blood pressure x 10(-3") were not significantly changed. The results are discussed in terms of a possible relationship between the reduction of STVM by verapamil and a reduction of the ischemic area.