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Implications of normal exercise electrocardiographic results in patients with angiographically documented coronary
Insights
False-negative exercise electrocardiography results are uncommon in coronary artery disease patients and linked to less severe disease. Exercise thallium imaging can detect most false-negative cases, aiding diagnosis.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Exercise Physiology
Background:
- Coronary artery disease (CAD) diagnosis relies on various methods, including exercise electrocardiography (ECG).
- False-negative results in exercise ECG can lead to underdiagnosis and delayed treatment.
- Understanding the characteristics and implications of false-negative exercise ECG is crucial for patient management.
Purpose of the Study:
- To determine the incidence of false-negative exercise ECG results in patients with documented CAD.
- To investigate the clinical and angiographic implications associated with these false-negative findings.
- To evaluate the utility of exercise thallium-201 imaging in identifying patients with false-negative exercise ECG results.
Main Methods:
- Retrospective analysis of 216 consecutive patients with angiographically confirmed CAD.
- Exercise ECG was performed, and results were categorized as true-positive, false-negative, or non-diagnostic.
- Exercise thallium-201 imaging was conducted in a subset of patients (n=88).
- Coronary artery disease extent was quantified using a scoring system.
- Comparison of clinical, ECG, angiographic, and imaging data between false-negative and true-positive groups.
Main Results:
- False-negative exercise ECG results were observed in 10.6% (23/216) of patients.
- Patients with false-negative results had significantly higher exercise heart rates (161 vs. 133 bpm, p<0.0001) and less extensive coronary artery disease (score 5.8 vs. 9.2, p=0.0025).
- Angina during exercise was less frequent in the false-negative group (p<0.01).
- No significant difference in Q-wave infarction or left ventricular asynergy was found between groups (p=NS).
- Exercise thallium-201 imaging identified significant coronary disease in 75% of patients with false-negative exercise ECG results.
Conclusions:
- False-negative exercise ECG results are infrequent in CAD patients and associated with less severe coronary artery disease.
- The frequency of prior infarction and resting left ventricular dysfunction does not differ between false-negative and true-positive exercise ECG groups.
- Exercise thallium-201 imaging is effective in detecting underlying coronary artery disease in patients with false-negative exercise ECG results, highlighting its value in diagnostic workup.
Abstract:
The purpose of this study was to examine the incidence and implications of false-negative exercise electrocardiographic results among 216 consecutive patients with angiographically documented coronary artery disease (50 percent diameter narrowing or greater of one or more vessels). Exercise electrocardiography gave negative (false-negative) results in 23 patients and positive (true-positive) results in 102 patients, and were nondiagnostic in the rest. Exercise thallium-201 imaging was performed in 88 patients. The extent of coronary artery disease was quantitated by a scoring system that takes into consideration the degree and site of narrowing in the major vessels and their branches. The exercise heart rate was higher in patients with false-negative than in patients with true-positive exercise electrocardiographic results (161 +/- 18 versus 133 +/- 24 beats per minute, mean +/- SD; p less than 0.0001). Q-wave infarction was present in two patients (9 percent) with false-negative and 20 patients (20 percent) with true-positive exercise electrocardiographic results (p = NS); left ventricular asynergy at rest was observed in 13 patients (57 percent) with false-negative and in 74 patients (74 percent) with true-positive results (p = NS). Patients with false-negative results had less extensive coronary disease than did patients with true-positive results (score 5.8 +/- 3.6 versus 9.2 +/- 5.0; p = 0.0025). Angina during exercise was less frequent in patients with false-negative results (p less than 0.01). Abnormal exercise thallium-201 images were seen in 15 of 20 patients (75 percent) with false-negative results and in 56 of 68 patients (82 percent) with true-positive results (p = NS). It is concluded that (1) false-negative exercise electrocardiographic results are infrequent (10 percent) among patients with coronary artery disease and are associated with less extensive coronary artery disease; (2) the frequency of Q-wave infarction and left ventricular asynergy is the same in patients with false-negative results as in patients with true-positive exercise electrocardiographic results; (3) exercise thallium images can identify 75 percent of patients with coronary disease and false-negative results of exercise electrocardiography.