Correlation of Resting ECG, Stress ECG & Thallium Scan in the Evaluation of Coronary Artery Disease

Abstract

INTRODUCTION:
One of the most challenging and frequent problems in clinical cardiology is the detection and extent of Coronary Artery Disease (CAD). The exercise ECG appears to be an excellent ‘method for screening but is limited by equivocal and falsely positive and negative results (Antonio, etal).Ten patients with chest pain had either normal or non-specific ECG changes and their exercise tolerance test was inconclusive or equiv ocal. 5 patients presented with resting ECG abnormalities of LBBB, RBBB, and ST, T chang es. These were the cases where exercise tolerance test could not be interpreted accurately.

METHODOLOGY:
Every patient was exercised according to the modified Bruce Protocol on a calibrated motor driven treadmill with the 12 leads ECG recording. Blood pressure was recorded using a cuff-sphygm omanometer before starting the exercise and at the end of every stage. Before starting the exercise a butterfly needle of 19-21 guage was placed in an arm vein with a saline syringe attached to it.

DISCUSSION:
Thallium a member of the heavy metal group of elements has had p biological use other than as a rat poison until its relatively recent application in myocardial imaging. Kewanae tal1 2 in 1970 first reported the successful imaging of the human heart with short lived Thallium Isotopes Lebowitz1 , etal at Brookh aven first discovered the most favourable Isot ope of Thallium,i.e.,Thallium 201 for external imaging.In the selected group of 70 patients that we studied it can be concluded that, TL2O1 Scan is not only of particualr use in patients with resting ECG abnormalities of LBBB, RBBB and ST, T changes where interpretation of exercise ECG becomes difficult, but is of particular importance in the evaluation of cases where coronary angiographic findings do not correlate with the patient’s symptoms.