Validity of a new exercise-induced QRS score for diagnosis of coronary artery disease

ABSTRACT

This study aimed to examine validity of a new exercise index [the QRS score] and compare its value with ST-segment depression as markers of ischemia. The study included 104 subjects, 64 patients with documented coronary artery disease [group I] and 40 normal subjects as controls [group II]. All subjects underwent a symptom limited treadmill exercise testing according to Bruce protocol. For each subject, QRS score was calculated and ST segment was evaluated. QRS score <5 mm detected coronary artery disease with a sensitivity of 90%, specificity of 85% and predictive accuracy of 87.5%; while for ST-segment depression, sensitivity was 61%, specificity 90% and predictive accuracy 70%. The value of QRS score was independent of the presence or absence of ST-segment depression. Also, there was a significant inverse relationship between value of QRS score and number of diseased coronary vessels. These data suggested that this new QRS score was a more useful and reliable index than ST-segment depression for the diagnosis of coronary artery disease