This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Moon, M. R. Articles by Ingels, N. B. Search for Related Content PubMed PubMed Citation Articles by Moon, M. R. Articles by Ingels, N. B.

(Circulation. 1997;95:1320-1327.)
© 1997 American Heart Association, Inc.

Articles

Septal Function During Left Ventricular Unloading

Marc R. Moon, MD; Ann F. Bolger, MD; Abe DeAnda, MD; Masashi Komeda, MD, PhD; George T. Daughters, II, MS; Srdjan D. Nikolic, PhD; D. Craig Miller, MD; Neil B. Ingels, Jr, PhD

the Department of Cardiovascular and Thoracic Surgery and the Division of Cardiovascular Medicine (A.F.B.), Stanford (Calif) University School of Medicine; Research Institute of the Palo Alto (Calif) Medical Foundation (G.T.D., S.D.N., N.B.I.); and Cardiac Surgery and Cardiology Sections (M.R.M., A.D., M.K., D.C.M.), Department of Veterans Affairs Medical Center, Palo Alto, Calif.

Correspondence to D. Craig Miller, MD, Department of Cardiovascular Surgery, Falk Cardiovascular Research Center, Stanford University Medical School, Stanford, CA 94305.

Background Left ventricular (LV) unloading with mechanical support devices alters biventricular geometry and impairs right ventricular (RV) contractility, but its effect on septal systolic function remains unknown.

Methods and Results To evaluate the effects of LV volume and pressure unloading on septal geometry and function, LV preload was abruptly reduced by clamping left atrial pressure between 0 and -2 mm Hg in seven open-chest, anesthetized dogs by use of a pressure-control servomechanism to withdraw blood from the left atrium. With left atrial pressure clamping, maximal LV pressure decreased 30±12% (mean±SD) (P<.0001) and LV end-diastolic cross-sectional area (determined by two-dimensional echocardiography) decreased by 53±16% (P<.0001). This caused the septum to shift toward the left (RV septal free-wall dimension increased; P<.004) and flatten (radius of curvature increased; P<.0002), while LV septal free-wall dimension fell (P<.0001). Septal end-diastolic thickness increased 23±15% (P<.0005), reflecting a decline in septal preload. Systolic septal thickening decreased (P<.002), while systolic septal output (Septal Output=Septal ThickeningxHeart Rate) fell from 30±17 to 15±22 cm/min (P<.002). This was associated with movement along the septal Frank-Starling equivalent (septal output versus end-diastolic septal thickness [preload] relation) to a less productive portion of the curve.

Conclusions LV unloading not only altered interventricular septal geometry but also reduced septal systolic thickening and output, all of which may contribute to impaired RV contractility during mechanical LV support.

Key Words: echocardiography • heart-assist device • ventricles • mechanics

This article has been cited by other articles:

				J. Mau, S. Menzie, Y. Huang, M. Ward, and S. Hunyor Chronic septal infarction confers right ventricular protection during mechanical left ventricular unloading J. Thorac. Cardiovasc. Surg., July 1, 2009; 138(1): 172 - 178. [Abstract] [Full Text] [PDF]

				K. B. Leissner, F. Mahmood, J. R. Aragam, A. Amouzgar, and R. Ortega Catecholamine-Induced Cardiomyopathy and Pheochromocytoma Anesth. Analg., August 1, 2008; 107(2): 410 - 412. [Full Text] [PDF]

				N. Hristov, O. J. Liakopoulos, G. D. Buckberg, and G. Trummer Septal structure and function relationships parallel the left ventricular free wall ascending and descending segments of the helical heart Eur. J. Cardiothorac. Surg., April 1, 2006; 29(Suppl_1): S115 - S125. [Abstract] [Full Text] [PDF]

				S. Saleh, O. J. Liakopoulos, and G. D. Buckberg The septal motor of biventricular function Eur. J. Cardiothorac. Surg., April 1, 2006; 29(Suppl_1): S126 - S138. [Abstract] [Full Text] [PDF]

				S. L. Gaynor, H. S. Maniar, S. M. Prasad, P. Steendijk, and M. R. Moon Reservoir and conduit function of right atrium: impact on right ventricular filling and cardiac output Am J Physiol Heart Circ Physiol, May 1, 2005; 288(5): H2140 - H2145. [Abstract] [Full Text] [PDF]

				R. S. Poston and B. P. Griffith Heart Transplantation J Intensive Care Med, January 1, 2004; 19(1): 3 - 12. [Abstract] [PDF]

				H. S. Maniar, S. M. Prasad, S. L. Gaynor, C. M. Chu, P. Steendijk, and M. R. Moon Impact of pericardial restraint on right atrial mechanics during acute right ventricular pressure load Am J Physiol Heart Circ Physiol, January 1, 2003; 284(1): H350 - H357. [Abstract] [Full Text] [PDF]

				U. P. Klima, M.-Y. Lee, J. L. Guerrero, P. J. LaRaia, R. A. Levine, and G. J. Vlahakes Determinants of maximal right ventricular function: Role of septal shift J. Thorac. Cardiovasc. Surg., January 1, 2002; 123(1): 72 - 80. [Abstract] [Full Text] [PDF]

				Y. Ochiai, S. Morita, Y. Tanoue, Y. Kawachi, R. Tominaga, and H. Yasui Effects of amrinone, a phosphodiesterase inhibitor, on right ventricular/arterial coupling immediately after cardiac operations J. Thorac. Cardiovasc. Surg., July 1, 1998; 116(1): 139 - 147. [Abstract] [Full Text]