Summary

Background: Previous studies have documented that reduction in QT dispersion after thrombolytic treatment in acute myocardial infarction depends on reperfusion status as well as infarct site. Primary percutaneous transluminal coronary angioplasty as compared with thrombolytic therapy has been shown to result in higher patency rates of the infarct vessel.

Objectives: To evaluate whether primary PTCA has a more favorable effect on reducing QT dispersion in patients with acute MI as compared to thrombolytic treatment.

Methods: The study population included 42 consecutive patients (33 men, mean age 58 ± 11 years) with acute Ml (24 anterior wall, 18 inferior wall) who were treated with primary PTCA (group A, n 21) or thrombolytic therapy (group B, n = 21) at 3.9+2 hours after symptom onset. QT intervals were measured before and 24 hours after treatment.

Results: On the admission electrocardiogram, patients with anterior Ml had higher values of QT and QTc dispersions than patients with inferior Ml (52±9 vs. 36±9 msec, R<0.05 and 61+4 vs. 56+4 msec, P=0.002, respectively). There was a significant reduction in QT and QTc dispersions from admission to 24 hours in all patients (from 50+9 to 37+9 msec, P<0.001 and from 59+5 to 42+5 msec, P<0.001. respectively), and also in group A (from 49±8 to 32±5 msec. P<0.001 and from 58+5 to 38+3 msec, P<0.001, respec­tively) and in group B patients (from 51+10 to 42+10 msec. P<0.01 and from 60±4 to 46±5 msec, P<0.001, respec­tively). QT and QTc dispersions were found to be shorter in group A at 24 hours after treatment than in group B (32 + 5 vs. 42+10 msec, P<0.001 and 38+3 vs. 46+5 msec, P<0.001. respectively).

Conclusions: Reperfusion therapy with primary PTCA or thrombolytic agents reduces QT and QTc dispersions in acute Ml. QT and QTc dispersions after reperfusion treatment are shorter with primary PTCA than with thrombolytic therapy.