Relationship between QT Interval Dispersion and Degree of Coronary Artery Disease

Abstract

Background: It has been shown that QT dispersion (QTD) increases during episodes. Currentstudyhas been done in order to determine QTD in patients with stable angina, assess myocardial ischemia and infarction. Aims of Study: This study aiming to determine the relationship between severity of coronary artery disease (CAD) and degree of QTD. Patients and Method: A 214 patients (177 men and 37 women) underwent diagnostic coronary angiography because of suspected CAD. Standard resting 12 lead electrocardiogram (ECG) were recorded within 24hrs before coronary angiography. QT intervals were measured manually by ruler method and QTD were gauged as (QT maximum – QT minimum). A 184 patients had CAD and control group (30 persons) had a normal coronary angiogram Interestingly, QTD has increased significantly as there was sever increment of CAD. QTD was in 1 vessel disease, 2 vessel disease, in 3 vessel disease, and in left main stem disease. Left ventricular dysfunction has raised QTD significantly in patients with 1,2 vessels, as well as left main stem disease. QTD clearly elevated as Gensini score increased. Involvement of proximal left anterior descending artery did not increase QTD significantly in patients with CAD. Multiple regression analysis demonstrated that severity of CAD, left ventricular dysfunction and previous myocardial infarction were independently associated with increased QTD. QTD increased significantly in patients with stable angina compared to the controls.Severity increase of CAD resulted in significant increase in QTD, and presence of LV dysfunction has caused further increase.