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Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics.

Publication ,  Journal Article
Spratt, JA; Olsen, CO; Tyson, GS; Glower, DD; Davis, JW; Rankin, JS
Published in: J Thorac Cardiovasc Surg
October 1983

It has been suggested that mitral valve replacement for mitral regurgitation can precipitate acute myocardial failure by increasing left ventricular afterload. However, most studies of this problem have involved anesthesia, acute surgical trauma, or ischemic cardioplegia, each of which can influence myocardial function. The pure hemodynamic consequences of mitral valve replacement were investigated by surgically instrumenting eight dogs with ultrasonic transducers to measure left ventricular diameter, electromagnetic flow probes to measure ascending aortic blood flow, and micromanometers to measure left ventricular and pleural pressures. At the time of implantation, an 8 mm stainless steel shunt was inserted through the left ventricular myocardium at the base of the anterior wall and sutured to the left atrial appendage, producing simulated mitral regurgitation of 20% to 40% of total ventricular output. Balloon occluders were placed around the left atrial shunt and both venae cavae. One to 7 days after implantation, each dog was studied in the conscious state, and data were recorded during acute occlusion of the shunt. After shunt occlusion, left ventricular mean ejection pressure increased significantly in all studies. Systolic wall tension also increased by an average of 8%, diameter shortening decreased by 21%, and forward cardiac output increased by 17%. Thus the higher afterload associated with elimination of mitral regurgitation produced an acute fall in stroke shortening and total left ventricular output. However, forward cardiac output increased in all studies, implying improved pump efficiency and overall cardiac performance. Thus the improvement in pump efficiency associated with restoration of mitral valve competence uniformly increases forward cardiac output despite an increased ventricular afterload and a decreased total stroke volume. Although there may be differences between this relatively acute model and chronic forms of mitral regurgitation encountered clinically, these data suggest that forward cardiac output should increase with correction of mitral regurgitation and that the associated augmentation in afterload is probably not a major factor causing low cardiac output after correction.

Duke Scholars

Published In

J Thorac Cardiovasc Surg

ISSN

0022-5223

Publication Date

October 1983

Volume

86

Issue

4

Start / End Page

479 / 489

Location

United States

Related Subject Headings

  • Stroke Volume
  • Respiratory System
  • Postoperative Complications
  • Mitral Valve Insufficiency
  • Mitral Valve
  • Hemodynamics
  • Heart Ventricles
  • Heart Valve Prosthesis
  • Heart
  • Dogs
 

Citation

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Spratt, J. A., Olsen, C. O., Tyson, G. S., Glower, D. D., Davis, J. W., & Rankin, J. S. (1983). Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics. J Thorac Cardiovasc Surg, 86(4), 479–489.
Spratt, J. A., C. O. Olsen, G. S. Tyson, D. D. Glower, J. W. Davis, and J. S. Rankin. “Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics.J Thorac Cardiovasc Surg 86, no. 4 (October 1983): 479–89.
Spratt JA, Olsen CO, Tyson GS, Glower DD, Davis JW, Rankin JS. Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics. J Thorac Cardiovasc Surg. 1983 Oct;86(4):479–89.
Spratt, J. A., et al. “Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics.J Thorac Cardiovasc Surg, vol. 86, no. 4, Oct. 1983, pp. 479–89.
Spratt JA, Olsen CO, Tyson GS, Glower DD, Davis JW, Rankin JS. Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics. J Thorac Cardiovasc Surg. 1983 Oct;86(4):479–489.
Journal cover image

Published In

J Thorac Cardiovasc Surg

ISSN

0022-5223

Publication Date

October 1983

Volume

86

Issue

4

Start / End Page

479 / 489

Location

United States

Related Subject Headings

  • Stroke Volume
  • Respiratory System
  • Postoperative Complications
  • Mitral Valve Insufficiency
  • Mitral Valve
  • Hemodynamics
  • Heart Ventricles
  • Heart Valve Prosthesis
  • Heart
  • Dogs