Related Experiment Videos
The effect of exercise-induced myocardial ischemia on postischemic left ventricular diastolic filling
M F Stoddard1, J Johnstone, S Dillon
1Cardiovascular Divsion, University of Louisville School of Medicine, Kentucky 40292.
Insights
Exercise-induced ischemia impairs left ventricular diastolic filling in humans. This postischemic effect was observed in patients with reversible or partially reversible thallium defects, but not in controls or those with fixed defects.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Left ventricular diastolic filling is crucial for cardiac function.
- Exercise can induce myocardial ischemia, potentially affecting diastolic function.
- Understanding postischemic effects is important for patient management.
Purpose of the Study:
- To investigate if exercise-induced ischemia impairs left ventricular diastolic filling in the postischemic period.
- To assess changes in mitral valve inflow dynamics after exercise in men with and without ischemic defects.
Main Methods:
- Studied 101 men (mean age 57 years) before and 2 hours after symptom-limited thallium-201 treadmill tests.
- Utilized pulsed Doppler echocardiography to assess mitral valve inflow.
- Categorized participants into ischemia, myocardial infarction-ischemia, control, and myocardial infarction groups based on thallium defects.
Main Results:
- Diastolic filling was significantly impaired in the ischemia and myocardial infarction-ischemia groups post-exercise.
- Key parameters like peak early filling velocity and peak early to atrial filling velocity ratio decreased significantly.
- No significant changes in diastolic filling were observed in the control or fixed defect myocardial infarction groups.
Conclusions:
- Exercise-induced ischemia demonstrably impairs left ventricular diastolic filling in the postischemic period in humans.
- The impairment is linked to reversible or partially reversible ischemic defects.
- Diastolic function remains unchanged in individuals without exercise-induced ischemia or with fixed defects.
Abstract:
To determine whether exercise-induced ischemia impairs left ventricular diastolic filling in the postischemic period in humans, 101 men (mean age 57 +/- 10 years) were studied before and 2 h after a symptom-limited thallium-201 tomographic treadmill with pulsed Doppler echocardiography of mitral valve inflow. In the postischemic period 2 h after exercise, diastolic filling was significantly impaired in the ischemia group (reversible thallium defect; n = 24) as reflected by a decrease in the peak early filling velocity (44.5 +/- 10.1 to 39.9 +/- 9.9 cm/s, p less than 0.01), peak early to atrial filling velocity ratio (0.91 +/- 0.27 to 0.76 +/- 0.25, p less than 0.001), and deceleration rate of early filling (281 +/- 104 to 245 +/- 86 cm/s2, p less than 0.01). Similar alterations in the postischemic period occurred in the myocardial infarction-ischemia group (partially reversible defect; n = 28) as seen by a decrease in the peak early filling velocity (47.6 +/- 11.6 to 41.8 +/- 12.0 cm/s, p less than 0.001), peak early to atrial filling velocity ratio (0.84 +/- 0.21 to 0.68 +/- 0.18, p less than 0.001), and early time-velocity integral (7.06 +/- 1.78 to 5.64 +/- 2.07 cm, p less than 0.001). In the control group (no defects; n = 33) and myocardial infarction group (fixed defect; n = 16), diastolic filling was unchanged in the postexercise period. Heart rate and blood pressure were unchanged post-exercise in all groups. Exercise-induced ischemia impairs diastolic filling in the postischemic period in humans.(ABSTRACT TRUNCATED AT 250 WORDS)