[Ventricular late potentials in myocardial infarction: comparison of thrombolysis, primary angioplasty, and conventional treatment]. / Etude des potentiels tardifs ventriculaires dans l'infarctus du myocarde: comparaison entre thrombolyse, angioplastie primaire et traitement conventionnel.

ABSTRACT

OBJECTIVES: The aim of this study was to compare the prevalence of ventricular late potentials (VLP) during the acute phase of myocardial infarction (MI) depending on the treatment used. METHODS AND RESULTS: This retrospective study was carried out over the period January 1992 to December 1997, and involved 238 patients admitted for primary MI and treated less than six hours after the onset of symptoms by intravenous thrombolysis (rt-PA, n = 83) or primary angioplasty (ATCI, n = 82) and in those cases treated over six hours after the onset of symptoms by standard treatment (heparin, n = 73). Rt-PA perfusion was considered to be effective when the three following criteria were simultaneously present i) pain sedation; ii) regression of the ST dysfunction > 50%; iii) creatine phosphokinase (CPK) peak before the 16th hour. Treatment success for angioplasty (ATCI+) was confirmed by a TIMI 3 (Thrombolysis in Myocardial Infarction) score for MI arterial perfusion, with residual stenosis of the MI artery of < 50%. Ventricular late potentials (VLP) were investigated between day six and 14, and considered to be present when two of the following criteria were met total duration of filtered QRS, i.e., QRSd > 114 ms; signal amplitude in the 49 last ms of filtered QRS, i.e., RMS40 < 20 mV, duration of the terminal part of filtered QRS that was below 40 mV, i.e., LAS40 > 38 ms (40 Hz). VLP prevalence was as follows 25% (rt-PA group), 345 (ATCI group), and 33% (standard treatment) respectively (P = NS). In the thrombolysis with reperfusion subgroup (n = 54/83, 65%), VLP incidence was 18.5% (n = 10/54) versus 35.5% (n = 27/76) in the subgroup ACTI+ (n = 76/82, 93%) (P = 0.03). CONCLUSIONS: The prevalence of VLP appears to be significantly decreased in the the case of thrombolysis with reperfusion compared to that observed in the ATCI+ group. One of the possible explanations for this abnormally high prevalence in the angioplasty group could be a dysfunction involving reocclusion after initially successful myocardial reperfusion therapy.