Objective: To evaluate factors influencing electrocardiogram (ECG) stress test.
Methods: The treadmill stress test and coronary angiogram (CAG) records were reviewed retrospectively in 435 consecutive patients with chest pain between 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 negative CAG and negative exercise test (true-negative, Group B). The baseline ECG, echocardiogram, abnormal systolic blood pressure response and history of diabetes mellitus and hypertension in the two groups were compared.
Results: There was no significant difference between the two groups with respect to age, gender, and antianginal medication. More patients in Group A had 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 echocardiogram 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 two groups with respect to maximal heart rate, maximal systolic blood pressure (BP), metabolic equivalents, postexercise systolic BP, termination for exercise test, baseline ECG with bundle branch block and ST depression.
Conclusion: Our results suggest that LV hypertrophy and a history of hypertension or diabetes mellitus are the main factors influencing ECG stress test for detecting coronary heart disease.