Copyright © 1992 by the European Society of Cardiology.
© 1992 The European Society of Cardiology
The effects of thrombolytic therapy on the high-resolution electrocardiogram after myocardial infarction
Helsinki University Central Hospital, First Department of Medicine, Cardiovascular Laboratory SF-00290 Helsinki, Finland Helsinki University of Technology, Laboratory of Biomedical Engineering, Department of Technical Physics SF-02150 Espoo Finland
Received 20 June 1991; revised 26 November 1991; .
Correspondence Markku M
kijm, MD, Helsinki University Central Hospital, First Department of Medicine, Cardiovascular Laboratory, SF-00290 Helsinki. Finland.
Abstract
The effects of thrombolytic treatment was studied in 109 consecutive patients 9–11 days after their first acute myocardial infarction by high-resolution electrocardiography (ECG), 24 h Holier monitoring, exercise test and radionuclide ventricu-lography. Thirty-seven patients were treated with intravenous thrombolytic agents. Thrombolytic treatment was assessed by clinical criteria to be successful in 22 patients and probably successful in 12 patients. Thrombolysis failed in three patients and 72 patients did not receive thrombolytic treatment (control group). Measurements made on the high-resolution and filtered (60 Hz high-pass) vectormagnitude complex included the total duration, the duration of the potential <40 µV, the root mean square (RMS) voltage in 10 ms intervals over the first 50 ms and RMS voltage of the last 40, 50 and 60 ms. The filtered QRS duration was significantly shorter in reperfused patients compared with the control group (83±10 vs 89± 12 ms; P = 0.017). In inferior infarcts (n = 57) the filtered QRS duration was 83±11 ms in reperf used and 89 ± 10 ms in non-repetfusedpatients (P = 0.044), but in anterior infarcts (n = 52) there was no difference. The RMS voltage of the initial 50 ms of the QRS was higher in the reperf used than in non-reperfusedanteroseptalinfarcts (38 ±14 v 23 ±10 µV; P = 0.022). Patients successfully treated with thrombolytic agents within the first 2 h had higher RMS voltage of the terminal 40 ms of the QRS than patients treated within 2–4 h (38 ±17 v 27 ±17 µV;P= 0.03). There were no significant differences in the duration of potential < 40 µV either in the initial or terminal QRS. The changes on the high-resolution ECG were not related to age, anti-arrhythmic drug therapy, the occurence of complex ventricular arrhythmias on the Holier recordings or during exercise, or left ventricular ejection fraction.
Key Words: Ventricular late potentials • high-resolution electrocardiography • myocardial infarction • thrombolytic therapy