Related Experiment Videos
Maximal vascular conductance in right ventricular myocardial circulation
G J Vlahakes1, E D Verrier, K Turley
1Cardiovascular Research Institute, University of California, San Francisco 94143.
The American Journal of Physiology
|April 1, 1994
Summary
Right ventricular hypertension increases diastolic coronary pressure, indicating impaired blood flow. This suggests increased filling pressures mediate these changes, impacting right coronary circulation.
Area of Science:
- Cardiovascular Physiology
- Coronary Circulation Research
Background:
- Right ventricular (RV) hypertension can lead to RV failure due to ischemia.
- Understanding the impact of RV hypertension on diastolic right coronary circulation is crucial.
Purpose of the Study:
- To investigate the effects of acute right ventricular hypertension on diastolic right coronary circulation.
- To determine the mechanisms underlying changes in diastolic coronary pressure-flow relations during RV hypertension.
Main Methods:
- Utilized conscious dogs instrumented for right coronary artery pressure and blood flow measurement.
- Maximal coronary vasodilation was induced using chromonar.
- Diastolic coronary pressure-flow relations (conductance and Pf=0) were assessed before and during RV hypertension, and after volume loading.
Main Results:
- Diastolic Pf=0 significantly increased during RV hypertension (11.8 to 17.1 Torr), while conductance remained unchanged.
- RV hypertension led to increased RV diastolic pressure.
- Volume loading mimicked the increase in diastolic Pf=0, suggesting mediation by elevated filling pressures.
Conclusions:
- Acute right ventricular hypertension impairs diastolic right coronary circulation.
- Increased filling pressures are a key mechanism contributing to altered diastolic coronary pressure-flow relations in RV hypertension.
- RV driving pressure can be used to calculate maximal right coronary conductance.