Key Points
- The study aims to evaluate how right ventricular hypertrophy affects myocardial blood flow distribution in dogs under pressure overload.
- Eighteen conscious dogs were subjected to chronic pressure overload via pulmonary artery constriction.
- Changes in right ventricular mass and fiber diameter were measured over 4-6 weeks or 4-5 months.
- Myocardial blood flow was assessed in both the right and left ventricles.
- Right ventricular mass increased by 45% and 110% after 4-6 weeks and 4-5 months, respectively.
- Transmural blood flow to hypertrophied right ventricle increased by 36% and 109% compared to normal values.
- No significant changes were observed in the capillary to muscle fiber number ratio despite the increased blood flow.
Structured PICO
Does chronic right ventricular pressure overload alter myocardial blood flow in conscious dogs?
PPopulation37 mongrel dogs of either sex (18 subjected to chronic pressure overload, 19 normal controls)
IInterventionChronic pressure overload of the right ventricle induced by pulmonary artery constriction for 4-6 weeks (moderate hypertrophy) or 4-5 months (severe hypertrophy)
CComparatorNormal dogs without pulmonary artery constriction, and the nonstimulated left ventricle as an internal control
OOutcomeOverall and regional distribution of myocardial blood flowsurrogate
Experimental right ventricular hypertrophy induced by pressure overload in conscious dogs is characterized by a sustained compensatory increase in coronary blood flow proportional to the augmented mass, without a proliferative response of the vasculature.
Limitations
- Preparation does not permit sampling of the venous effluent from the hypertrophied right ventricle, preventing direct measurements of right ventricular oxygen consumption