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Mechanism of exercise-induced hypotension in coronary artery disease
A S Iskandrian1, J G Kegel, J Lemlek
1Philadelphia Heart Institute, Presbyterian Medical Center, Pennsylvania 19104.
Insights
Hypotension during exercise testing in coronary artery disease (CAD) patients is not consistently linked to more severe disease or poorer prognosis. This study found similar cardiac abnormalities between patients with and without exercise-induced hypotension.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Hypotension during exercise testing is traditionally viewed as a marker for extensive coronary artery disease (CAD) and poor prognosis.
- The underlying mechanisms and clinical significance of this phenomenon require further elucidation.
Purpose of the Study:
- To investigate the mechanism of hypotension during exercise testing in patients with coronary artery disease (CAD).
- To compare the characteristics and extent of CAD in patients who develop hypotension versus those with a normal blood pressure response during exercise testing.
Main Methods:
- Compared 25 CAD patients with exercise-induced hypotension (Group 1) to 25 CAD patients with normal blood pressure response (Group 2).
- Assessed demographic data, clinical history, exercise parameters, and single-photon emission computed tomographic (SPECT) thallium imaging findings.
- Analyzed systolic blood pressure (BP) changes, heart rate, exercise duration, ST-segment depression, angina, and thallium uptake patterns.
Main Results:
- Groups were comparable in age, sex, extent of CAD, prior myocardial infarction, ejection fraction, hypertension history, and medications.
- Exercise heart rate, duration, ST-segment depression, angina occurrence, and SPECT thallium abnormalities (extent and severity) were not significantly different between groups.
- Inferior/posterior ischemia and increased lung thallium uptake were also similar in both groups.
Conclusions:
- Exercise-induced hypotension in CAD patients may not be a reliable indicator of extensive coronary disease or a worse prognosis.
- The findings suggest that other factors, beyond the extent of CAD, might contribute to hypotension during exercise.
- Further research is needed to fully understand the mechanisms and implications of exercise-induced hypotension in CAD.
Abstract:
Hypotension during exercise testing has been considered a marker of extensive coronary artery disease (CAD) and poor prognosis. The mechanism of hypotension was examined in 25 CAD patients who developed hypotension during treadmill exercise testing (mean decrease in systolic blood pressure [BP] 33 +/- 13 mm Hg) (group 1) and was compared with the results of 25 CAD patients who had a normal systolic BP response to exercise (mean increase 53 +/- 15 mm Hg) (group 2). The 2 groups were comparable in age, sex, extent of CAD, previous myocardial infarction, left ventricular ejection fraction, history of hypertension and cardiac medications. Exercise heart rate (121 +/- 23 vs 133 +/- 25 beats/min; p = not significant [NS]) and duration (6 +/- 2 vs 7 +/- 3 minutes; p = NS) were comparable. ST-segment depression occurred in 44% of patients in group 1 and in 52% in group 2 (p = NS), and angina during exercise occurred in 60% of both groups. Single-photon emission computed tomographic thallium images were abnormal in 24 patients (96%) in group 1 and in 20 patients (80%) in group 2 (p = NS). Percent thallium abnormality was 19 +/- 12% in group 1, and 18 +/- 14% in group 2 (p = NS), and the severity of thallium abnormality was 710 +/- 510 in group 1, and 510 +/- 500 in group 2 (p = NS). Ischemia involving the inferior/posterior segments was seen in 68% of patients in group 1 and in 60% in group 2 (p = NS). Increased lung thallium uptake was seen in 48% of both groups.(ABSTRACT TRUNCATED AT 250 WORDS)