Related Experiment Videos
Cardiac outcomes in coronary patients with submaximum dobutamine stress echocardiography
R S Ballal1, M A Secknus, R Mehta
1Department of Cardiology, Cleveland Clinic Foundation, Ohio 44195, USA.
Insights
Patients with submaximum heart rate response to dobutamine stress echocardiography have high cardiac event rates. A negative test result in these individuals is considered nondiagnostic for predicting cardiac events.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Clinical Medicine
Background:
- Dobutamine stress echocardiography (DSE) is a key tool for assessing cardiac risk.
- Submaximum heart rate response to DSE (<85% age-predicted) poses challenges in risk stratification.
- Limited data exists on cardiac event prediction in patients with inadequate chronotropic response to DSE.
Purpose of the Study:
- To evaluate the predictive value of DSE for cardiac events in patients with submaximum heart rate response.
- To determine if inducible abnormalities on DSE influence cardiac event rates in this specific patient group.
Main Methods:
- Retrospective analysis of 1,772 patients undergoing DSE.
- Focus on 255 patients with submaximum heart rate response, excluding beta-blocker users.
- Follow-up for cardiac events including cardiac death, myocardial infarction, unstable angina, and revascularization.
Main Results:
- High rates of cardiac events (31%) observed in patients with submaximum heart rate response.
- Cardiac event rates were similar regardless of inducible abnormalities (36% vs. 31%, p=NS).
- Cardiac death (11%) and unstable angina (15%) were significant components of the observed events.
Conclusions:
- Inadequate chronotropic response to DSE is associated with a high incidence of cardiac events.
- A negative DSE in patients with submaximum heart rate response should be interpreted cautiously and considered nondiagnostic.
- Risk stratification in this population requires careful consideration beyond DSE findings alone.
Abstract:
This study evaluated the prediction of cardiac events (cardiac death, myocardial infarction, unstable angina, or late myocardial revascularization) in patients with submaximum responses to dobutamine stress, defined by attainment of <85% age-predicted heart rate. Of 1,772 patients undergoing dobutamine echocardiography over a 2-year period, 425 had a submaximum heart rate response. After exclusion of patients treated with beta-adrenoceptor blocking agents, 255 patients formed the study group. In these patients, the test was terminated after administration of the maximum dose of 40 microg/kg/min of dobutamine with atropine (end of protocol, n = 186), severe angina, ischemic ST-segment changes, or intolerable side effects (n = 69). Dobutamine-induced changes (ischemia, viability, or both) were detected in 46 patients, involving ischemia in 133 segments, viability in 23, and ischemia and viability in 16 segments. Patients were followed for an interval of 28 +/- 17 months; 5 (1.2%) were lost to follow-up. Of the medically treated patients, cardiac events occurred in 73 of 228 (31%), including cardiac death in 25 (11%), nonfatal myocardial infarction in 11 (4.8%), severe unstable angina in 35 (15%), and late revascularization in 2 (0.9%). Cardiac events occurred in 11 of 30 (36%) with inducible abnormalities, and 62 of 198 without inducible abnormalities (31%, p = NS). Thus, cardiac event rates are high in patients with inadequate chronotropic responses to dobutamine stress, irrespective of whether stress-induced changes are detected. A negative dobutamine echocardiogram at submaximum heart rate should be considered nondiagnostic.