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Relation of exercise Doppler left ventricular filling to thallium lung uptake
R S Finkelhor1, C L Ramer, M Castellanos
1Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH 44109.
Insights
Patients with coronary artery disease and exercise pulmonary congestion show higher early diastolic filling (E) post-exercise. This suggests elevated left atrial pressure during exercise in these individuals.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Exercise-induced changes in left ventricular filling in coronary artery disease (CAD) patients are not well understood.
- Pulmonary venous congestion during exercise is a significant clinical concern in CAD.
Purpose of the Study:
- To investigate exercise-induced changes in left ventricular (LV) filling patterns in CAD patients.
- To correlate LV filling dynamics with a noninvasive indicator of exercise pulmonary venous congestion, the lung-to-heart (L:H) ratio.
Main Methods:
- Fifty-six patients with CAD underwent symptom-limited thallium stress testing.
- Doppler echocardiography assessed LV filling (early (E) and late (A) filling velocities, ratio, diastolic time-velocity integral, diastolic filling time) pre- and post-exercise.
- The L:H ratio was determined from stress testing; abnormal was defined as >95% confidence limit in normal subjects.
Main Results:
- Among 50 subjects with adequate Doppler data, 20 had abnormal L:H ratios.
- Post-exercise, the abnormal L:H group showed a significantly higher early filling velocity (E) (87 cm/sec vs. 68 cm/sec, p < 0.01) compared to the normal L:H group.
- The change in E from rest to post-exercise was also significantly different between groups (p < 0.05).
Conclusions:
- Elevated early diastolic LV filling velocity (E) after exercise in CAD patients with abnormal L:H ratios suggests increased pulmonary venous congestion.
- Higher E post-exercise correlates with higher early diastolic left atrial pressure during exercise in these patients.
Abstract:
The exercise-induced changes in left ventricular filling in patients with coronary artery disease are poorly understood. Therefore these changes were studied in relation to a noninvasive indicator of exercise pulmonary venous congestion, the lung-to-heart (L:H) ratio on symptom-limited thallium stress testing. Fifty-six patients undergoing diagnostic treadmill testing were studied; 50 of them had technically adequate Doppler recordings and became the subjects of this study. Doppler left ventricular filling was assessed with patients in the supine position both before and after exercise. Measurements included early (E) and late (A) filling velocities, their ratio, the diastolic time-velocity integral, and the diastolic filling time. The L:H ratio was considered abnormal if it was greater than the upper 95% confidence limit for a separate group of normal subjects. Twelve subjects had a documented prior myocardial infarction, 16 had stress-induced ischemia, and 20 had abnormal L:H ratios. A greater E and a longer diastolic filling time in the group with an abnormal L:H ratio were the only postexercise measurements that differed; however, E was the only filling parameter that both differed between groups after exercise (abnormal L:H group 87 +/- 25 cm/sec; normal 68 +/- 20 cm/sec; p < 0.01) and whose change from rest to after exercise was significantly different (p < 0.05). Since Doppler velocities are directly related to instantaneous gradients, the higher E in patients with evidence of exercise pulmonary congestion suggests a higher exercise early diastolic left atrial pressure.