Right and left ventricular volumes and function after acute pulmonary hypertension in the intact dog. Dell, Louis J., Douglas J. Pearce, Gerald G. Blackwell, H. Ross Singleton, Sanford P. Bishop, Gerald M. Pohost. Birmingham Veteran Affairs Medical Center, University of Alabama at Birmingham, Department of Medicine, Division of Cardiology, University Station, Birmingham, Alabama 35294. This study was supported by the Office of Research and Development, Medical Service, Department of Veteran Affairs (LJD), HD SCOR HL 17667, AHA (Alabama Affiliate), and Philips Medical Systems, Shelton Connecticut.
APStracts 2:0087A, 1995.
A canine model was developed to record right and left ventricular volumes and high-fidelity pressures during acute pulmonary hypertension without the need for major surgery. In this study new methodology was applied to record high-fidelity right ventricular (RV) and left ventricular (LV) pressures during magnetic resonance imaging (cine-MR) of the heart before and after acute pulmonary hypertension in 6 anesthetized, intact dogs where the pericardium and thorax were never disturbed by any surgical procedure. After pulmonary embolus, RV systolic pressure increased from 27 + 2 to 43 + 8 mmHg (SD) (p < 0.01) as LV systolic pressure decreased (97 + 17 to 76 + 3 mmHg, p < 0.05). Stroke volume (26+7 to 21+5 ml, p< 0.05) and RV ejection fraction (45 + 9 to 28 + 3%, p< 0.01) decreased as left LV ejection fraction was unchanged (50 + 5 to 52 + 5%, P=NS). LV end-diastolic pressure decreased from 11 + 4 to 7 + 3 mmHg (p < 0.05) and RV end-diastolic pressure increased from 6 + 3 to 11 + 3 mmHg (p < 0.01). RV end-diastolic volume increased from 57 + 14 to 75 + 20 (p < 0.01) as LV end-diastolic volumes decreased from 53 + 11 to 42 + 10 ml (p < 0.01) resulting in no change in total ventricular volume at end-diastole (111 + 24 to 116 + 28 ml). The observed mean decrease of 4.0 mmHg and 11 ml in LV end-diastolic pressure and volume was associated with no change in total ventricular volume. Taken together, these results suggest a lack of evidence for pericardial restraint. The measurement of total ventricular volume using cine-MR provides new information that complements other studies in which right ventricular volume was not recorded due to its complex geometry. This methodology allows an assessment of ventricular volumes and geometry that can be measured repeatedly without ever disturbing the pericardium or thorax. 

Received 19 May 1994; accepted in final form 27 January 1995.
APS Manuscript Number A512-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 21 March 1995.