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Comparison of ischemic response during exercise and dobutamine echocardiography in patients with left main coronary
C H Attenhofer1, P A Pellikka, J K Oh
1Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA.
Insights
Exercise and dobutamine echocardiography show similar sensitivity for detecting myocardial ischemia in left main coronary artery disease. However, exercise stress more frequently causes left ventricular dilation and ST depression compared to dobutamine stress.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Echocardiography
Background:
- Exercise testing reveals severe coronary artery disease through left ventricular dilation, ST depression, and blood pressure decrease.
- The comparable efficacy of dobutamine echocardiography in eliciting these signs remains undescribed.
Purpose of the Study:
- To compare the manifestations of myocardial ischemia induced by exercise versus dobutamine echocardiography in patients with left main coronary artery disease.
Main Methods:
- Fifty-four patients with significant left main stenosis underwent stress echocardiography (36 exercise, 18 dobutamine) and coronary angiography.
- Evaluated parameters included ECG/blood pressure changes, symptoms, wall motion, and diagnostic sensitivity.
- Left ventricular volumes and ejection fraction were quantified in 47 patients.
Main Results:
- Both methods demonstrated high sensitivity (91%) for stress-induced wall motion abnormalities.
- Exercise stress resulted in significantly more ST depression (p=0.005) and a trend towards higher rate-pressure product and wall motion score index.
- Exercise induced greater decreases in ejection fraction and increases in ventricular volumes compared to dobutamine.
Conclusions:
- Dobutamine and exercise echocardiography exhibit comparable sensitivity for diagnosing myocardial ischemia in left main coronary artery disease based on regional wall motion.
- Conventional indicators of severe ischemia, such as left ventricular dilation and marked ST depression, are more prevalent during exercise stress testing.
Objectives:
This study sought to compare manifestations of myocardial ischemia evoked by exercise and dobutamine echocardiography in patients with left main coronary artery disease.
Background:
During exercise testing, left ventricular cavity dilation, marked ST segment depression and blood pressure decrease indicate severe coronary artery disease. Whether these signs are comparably evoked by dobutamine echocardiography has not been described.
Methods:
Fifty-four patients who underwent stress echocardiography (36 exercise, 18 dobutamine) and coronary angiography showing > or = 50% left main stenosis were analyzed. Electrocardiographic and blood pressure changes, symptoms, wall motion score indexes and sensitivity for coronary artery disease were compared. In 47 patients, the left ventricular endocardium was traced to quantify volumes and ejection fraction.
Results:
Stress-induced regional wall motion abnormalities developed in 91% of patients; this was not different on exercise (89%) or dobutamine echocardiography (94%). Rate-pressure product and wall motion score index, similar at rest, tended to be higher after exercise than after dobutamine stress (p = 0.07 and p = 0.05, respectively). ST segment depression > or = 1 mm was more common with exercise (p = 0.005). Ejection fraction and end-systolic and end-diastolic volume indexes were comparable at rest in both groups. With exercise, ejection fraction decreased in 87% of patients, and end-systolic and end-diastolic volume indexes increased in 80%. In contrast, with dobutamine, decreased ejection fraction and increased volume indexes were infrequent. Ejection fraction was lower ([mean +/- SD] 45 +/- 19% vs. 54 +/- 12%, p = 0.007) and end-diastolic (69 +/- 26 vs. 50 +/- 17 ml/m2, p =0.02) and end-systolic (39 +/- 20 vs. 24 +/- 13 ml/m2, p = 0.02) volume indexes were higher after exercise than after dobutamine stress.
Conclusions:
On the basis of changes in regional wall motion both dobutamine and exercise echocardiography have a comparable high sensitivity in diagnosing myocardial ischemia in left main coronary artery disease. However, conventional signs of severe myocardial ischemia, including left ventricular cavity dilation and marked ST segment depression, occur more often with exercise than with dobutamine echocardiography.