Effect of exercise on QT dispersion

Electrocardiogram (ECG) is the measurement of potential differences occurring on the body due to the currents that flow on the heart during diastole and systole. Cardiac abnormalities cause uncommon current flows, leading to strange waveform morphologies in the recorded ECG. Since some abnormalities become visible in ECG only during activity, exercise ECG tests are conducted. Among all abnormalities, exercise induced ischemia is considered in this study. The previous studies have shown that exercise induced ischemia increases the QT dispersion (QTD). The patients in this study have been validated by cardiologists using ST segment analysis. However, the sensitivity and specifity of ST segment analysis is low. Some of the patients have been validated as ischemic using the coronary angiography results. A different method to measure the QT interval through out the exercise ECG test has been developed . The algorithm is designed to cope with the artifacts of exercise ECG. Such as high noise level and PT fusion. A different approach to obtain the QTD has been developed.We have shown that, QTD increases signiflcantly in patients who have ischemia during exercise. The sensitivity and specifity of exercise ECG test can be increased if QTD analysis is used as an additional tool to ST analysis.