Effect of thrombolytic therapy on QT dispersion in patients with acute myocardial infarction

ABSTRACT

QT dispersion is an important ECG feature fundamental for initiation of ventricular fibrillation and increased after myocardial infarction. to correlate site of infarction and QT dispersion and assess the effect of thrombolysis on it in patients with acute myocardial infarction [AMI]. The study include 100 patients with AMI were classified into 3 groups 01 included 30 patients received streptokinase [SK] with successful reperfusion, 02 30 patients received streptokinase with failed reperfusion and 03 included 40 patients not received SK due to contra-indications. all patients were subjected to resting 12 leads ECG at admission, 2 hours post SK [in G1 and G2] and predischarge. the following parameters were measured [QT interval, QRS interval, JT interval, PR interval, QT dispersion, JT dispersion, QRS dispersion, rate corrected QT, rate corrected JT, QTc dispersion and JTc dispersion]. The study reavles the QTd and JTd values significantly increased in patients < 50 years than pts > 50 years [p < 0.05]; QTd, JTd, QTcd and JTcd were significantly increased with anterior MI than inferior MI [p <0.001]. Among risk factors for coronary artery disease, QTcd and JTcd significantly increased in none obese pts [p < 0.05], QTd, QTcd, JTd, JTcd and QTc significantly increased in diabetics [p < 0.05], while in hypertensives, QTd, QTcd, JTd, JTcd and JTc are significantly increased [p <0.01]. The highest incidence of arrhythmia was in 01 and greater with anterior MI than inferior MI. QTd, JTd, QTcd and JTcd were longer in cases complicating arrhythmia and largest with ventricular fibrillation. In G1, QTd, JTd and QTcd were significantly increased at pre- discharge than at admission [p = 0.001] and than 2 hours after SK [p = 0.001] in G2, QTcd and JTcd significantly decreased 2 hrs after SK [p = 0.05], QTc, JTc, QTcd and JTcd decreased significantly at predischarge than at admission [p < 0.05], in G3, QTc and JTc significantly decreased at pre-discharge than at admission [p 0.001]. Conclusion The study concluded that QT dispersion is increased after myocardial infarction and showed significant rduction with successful thrombolysis. QTd is influenced by hypertension, diabetes mellitus, age and site of myocardial infarction. It could be used equally to QT for analysis: