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Abnormal transoesophageal Doppler coronary flow reserve in patients with dilated cardiomyopathy: relationship to
Z Chati1, J F Bruntz, G Ethévenot
1Department of Cardiology, Hôpital Jeanne d'Arc, Nancy, France.
Insights
Abnormal myocardial blood flow is common in dilated cardiomyopathy but does not limit exercise capacity. This study found reduced coronary flow reserve in patients, yet it did not correlate with their exercise limitations.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Dilated cardiomyopathy is associated with impaired myocardial function.
- Abnormal myocardial blood flow is a potential contributor to reduced cardiac function.
Purpose of the Study:
- To investigate if abnormal myocardial blood flow contributes to exercise capacity limitations in dilated cardiomyopathy patients.
- To assess coronary flow reserve in dilated cardiomyopathy and its relation to exercise capacity.
Main Methods:
- Assessed coronary flow reserve using transesophageal Doppler echocardiography in 16 dilated cardiomyopathy patients and 9 controls.
- Measured peak systolic and diastolic coronary flow velocities at rest and after dipyridamole infusion.
- Calculated coronary flow reserve as the ratio of hyperemic to basal flow velocities.
Main Results:
- Patients with dilated cardiomyopathy had significantly lower coronary flow reserve compared to controls (P < 0.001).
- Baseline coronary flow velocities were higher in patients.
- Coronary flow reserve did not correlate with peak VO2 or exercise time in patients.
Conclusions:
- Confirms previously observed abnormalities in coronary flow reserve in dilated cardiomyopathy.
- Suggests that abnormal coronary flow reserve does not limit exercise capacity in these patients.
Abstract:
1. In patients with dilated cardiomyopathy, abnormal myocardial blood flow may contribute to poor myocardial function. 2. The aim of this study was to investigate the possible contribution of abnormal myocardial blood flow to the limitation of exercise capacity in patients with dilated cardiomyopathy. 3. Coronary flow reserve was assessed in 16 patients with dilated cardiomyopathy and 9 matched normal control individuals. All participants had angiographically normal coronary arteries. At rest and after dipyridamole infusion (0.56 mg/kg intravenously), peak systolic and diastolic coronary flow velocities were measured in the proximal left anterior descending coronary artery using transoesophageal pulsed Doppler echocardiography, guided by colour flow imaging. Coronary flow reserve was calculated as the ratio of hyperaemic to basal diastolic and systolic peak coronary flow reserve. 4. Baseline diastolic and systolic coronary flow velocities were significantly higher in patients (50 +/- 6 and 30 +/- 4 cm/s respectively) compared with control individuals (37 +/- 3 and 20 +/- 1 cm/s respectively) (mean +/- S.E.M.) (P < 0.05). Diastolic and systolic peak coronary flow reserve were significantly lower in patients (1.60 +/- 0.14 and 1.40 +/- 0.09 respectively) compared with control individuals (2.89 +/- 0.15 and 2.17 +/- 0.17 respectively) (P < 0.001). Although peak VO2 and exercise time were significantly lower in patients compared with control individuals, coronary flow reserve did not correlate to exercise capacity in patients with dilated cardiomyopathy. 5. These results confirm the abnormalities of coronary flow reserve previously observed in patients with dilated cardiomyopathy, but suggest that such abnormalities do not contribute to the limitation of exercise capacity in these patients.