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Published on: June 28, 2019
Target heart rate to determine the normal value of coronary flow reserve during dobutamine stress echocardiography
Ezequiel H Forte1, Maria G Rousse, Jorge A Lowenstein
1Investigaciones Médicas, Buenos Aires, Argentina. ezeforte@yahoo.com
Insights
Dobutamine stress echocardiography is a feasible method for assessing coronary flow reserve (CFR) in the left anterior descending artery. A heart rate increase of 50 bpm or reaching 75% of maximum predicted heart rate is sufficient for adequate CFR analysis.
Area of Science:
- Cardiovascular Medicine
- Diagnostic Imaging
- Interventional Cardiology
Background:
- Coronary flow reserve (CFR) is crucial for managing ischemic heart disease.
- Dobutamine stress echocardiography (DSE) is a common pharmacological test for CFR evaluation.
- Optimal heart rate targets for DSE in CFR assessment remain unclear.
Purpose of the Study:
- To determine coronary flow velocity at each DSE stage.
- To identify the heart rate threshold for doubling baseline coronary flow velocity in the LAD artery.
Main Methods:
- 33 low-risk patients underwent DSE.
- Transthoracic color-Doppler echocardiography assessed LAD coronary artery flow velocity.
- Feasibility and correlation with heart rate changes were analyzed.
Main Results:
- High feasibility (94%) for CFR determination in the LAD during DSE.
- Mean CFR was 2.67 at the end of the test.
- A heart rate increase of 50 bpm correlated with CFR ≥ 2; 96.4% achieved CFR ≥ 2 at 75% max predicted heart rate.
Conclusions:
- DSE is a highly feasible method for assessing LAD coronary flow reserve.
- A delta heart rate of 50 bpm or reaching 75% of maximum predicted heart rate is sufficient for adequate CFR analysis.
Background:
The determination of coronary flow reserve (CFR) is an essential concept at the moment of decision-making in ischemic heart disease. There are several direct and indirect tests to evaluate this parameter. In this sense, dobutamine stress echocardiography is one of the pharmacological method most commonly used worldwide. It has been previously demonstrated that CFR can be determined by this technique. Despite our wide experience with dobutamine stress echocardiography, we ignored the necessary heart rate to consider sufficient the test for the analysis of CFR. For this reason, our main goal was to determine the velocity of coronary flow in each stage of dobutamine stress echocardiography and the heart rate value necessary to double the baseline values of coronary flow velocity in the territory of the left anterior descending (LAD) coronary artery.
Methods:
A total of 33 consecutive patients were analyzed. The patients included had low risk for coronary artery disease. All the participants underwent dobutamine stress echocardiography and coronary artery flow velocity was evaluated in the distal segment of LAD coronary artery using transthoracic color-Doppler echocardiography.
Results:
The feasibility of determining CFR in the territory of the LAD during dobutamine stress echocardiography was high: 31/33 patients (94%). Mean CFR was 2.67 at de end of dobutamine test.There was an excellent concordance between delta HR (difference between baseline HR and maximum HR) and the increase in the CFR (correlation coefficient 0.84). In this sense, we found that when HR increased by 50 beats, CFR was ≥ 2 (CI 93-99.2%). In addition, 96.4% of patients reached a CFR ≥ 2 (IC 91.1 - 99%) at 75% of their predicted maximum heart rate.
Conclusions:
We found that the feasibility of dobutamine stress echocardiography to determine CFR in the territory of the LAD coronary artery was high. In this study, it was necessary to achieve a difference of 50 bpm from baseline HR or at least 75% of the maximum predicted heart rate to consider sufficient the test for the analysis of CFR.
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