both control conditions and ischemia-induced vasodil-atation was studied in eight chronically instrumented awake dogs. Seven of these animals had coarctation-banding ofthe ascending aorta performed at 6 wk of age, and the other dog had congenital subvalvular aortic stenosis. The mean left ventricular weight for the group was 157±7.6 g, and the left ventricular body weight ratio was 8.76+0.47 g/kg. None ofthe animals exhibited signs of congestive heart failure. During the control state, the mean left ventricular systolic pressure was 249+12 mm Hg and the left ventricular end-diastolic pressure was 11.5±0.5 mm Hg. The aortic diastolic pressure was 74±6 mm Hg. Mean left circumflex coronary artery blood flow was 71±6 cm3/min. In the animals with coarctation-band-ing, 52±6 % of the flow occurred during systole. In the dog with congenital subvalvular aortic stenosis, 5 % of the coronary flow was systolic. Mean transmural blood flow during resting conditions was 0.97±0.08 cm3/min per g, and the ratio of endocardial to epicar-dial flow (endo/epi) was 0.88±0.07. During reactive hyperemia, the mean transmural blood flow increased to 3.5±0.30 cm3/min per g; however, the endo/epi decreased to 0.52±0.06. These studies document a difference in transmural blood flow distribution between the normal and the hypertrophied left ventricle: during resting conditions, in the normal ventricle, the highest flow occurs in the endocardial layer, whereas in the hypertrophied ven-tricle, the highest flow is in the middle layers with the endocardial flow less than the epicardial flow.

SCHEUER. Coronary collateral stimulatim by exercise in dogs with stenotic coronary arteries. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52 ( 3): 664-671,1982.-To determine the effects of an exercise-training program on coronary collat-eral development, we instrumented 13 l-y-r-old beagles with left circumflex (LCf) coronary artery flow probes and balloon oc-eluders and left atria1 and aortic catheters. The LCf artery was constricted resulting in a 58 * 4 % reduction of the peak reactive hyperemia response following release of a 15-s LCf occlusion. All dogs were studied during the first week of the study protocol. Resting heart rate, cardiac output, and left atria1 and aortic pressures were evaluated before and during a I-min LCf occlu-sion. Myocardial blood flow was also measured with radioac-tively-labeled microspheres injected into the left atrium during the LCf occlusion. Subsequently the dogs were exercised at 6.4

Abstract: Despite ample evidence that right ventricular function is a critical determinant of the clinical response to a spectrum of cardiovascular diseases, there has been only a limited analysis of the unique and distinguishing physiologic properties of the RV under normal circumstances and in response to pathologic insults. This review highlights some of these features and underscores the fact that rational therapy in RV failure should acknowledge this physiology and ought to be chamber specific.

Copyright © 2014 Korakot Nganvongpanit et al.This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in anymedium, provided the originalwork is properly cited. This study aimed to determine whether swimming could improve function of osteoarthritic joints in canine hip OA. Fifty-five dogs were categorized into three groups.TheOAwith swimming group (OA-SW;