An analysis of factors influencing electrocardiogram stress test for detecting coronary heart disease

Objective To evaluate factors influencing electrocardiogram (ECG) stress te st. Methods The treadmill stress test and coronary angiogram (CAG) records were reviewed retrospectively in 435 consecutive patients with chest pain betwe en 1991 and 1997. There were 44 cases with normal CAG but positive exercise stress test results (false-positive, Group A), and 33 cases with both nega tive CAG and negative exercise test (true-negative, Group B) The baseline E CG, echocardiogram, abnormal systolic blood pressure response and history o f diabetes mellitus and hypertension in the two groups were compared. Results There was no significant difference between the two groups with res pect to age, gender, and antianginal medication. More patients in Group A h ad hypertension (52.3% vs 27.3%, P < 0.05) and diabetes mellitus (15.9% vs 0%, P < 0.05). Left ventricular (LV) hypertrophy in baseline ECG and by ech ocardiogram was more often present in Group A (25.0% vs 3.0%, P < 0.05; 36. 4% vs 12.1%, P < 0.05). There were no significant differences between the t wo groups with respect to maximal heart rate, maximal systolic blood pressu re (BP), metabolic equivalents, postexercise systolic BP, termination for e xercise test, baseline ECG with bundle branch block and ST depression. Conclusion Our results suggest that LV hypertrophy and a history of hyperte nsion or diabetes mellitus are the main factors influencing ECG stress test for detecting coronary heart disease.