This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Steine, K. Articles by Smiseth, O. A. Search for Related Content PubMed PubMed Citation Articles by Steine, K. Articles by Smiseth, O. A.

EXPERIMENTAL STUDY

Mechanisms of diastolic intraventricular regional pressure differences and flow in the inflow and outflow tracts

Kjetil Steine, MD, PhD^*,*, Marie Stugaard, MD, PhD and Otto A. Smiseth, MD, PhD, FACC

^* Medical Department, Aker University Hospital, Oslo, Norway
Institute for Surgical Research, Rikshospitalet, University of Oslo, Oslo, Norway

Manuscript received April 9, 1999; revised manuscript received May 13, 2002, accepted May 24, 2002.

^* Reprint requests and correspondence: Dr. Kjetil Steine, Medical Department, Aker University Hospital, Trondheimsvn. 235, N-0514 Oslo, Norway.
kjetil.steine{at}ioks.uio.no

OBJECTIVES: We sought to investigate the mechanisms of left ventricular (LV) intracavitary early diastolic flow during changes in contractility and loading.

BACKGROUND: There is limited understanding of how intracavitary flow velocities relate to intraventricular driving pressures.

METHODS: In 12 anesthetized dogs, we measured pressures in the left atrium (LA), LV at the mitral tip, apex, and subaortic region; intraventricular velocities by color M-mode Doppler echocardiography (CMD); and volume by sonomicrometry. We also investigated responses to isoprenaline, ischemic failure, and volume loading.

RESULTS: During rapid, early filling, the mitral to apical pressure gradient (LVP_mitral-apex) correlated with the peak mitral to apical velocity (r = 0.92). The LVP_mitral-apex increased from 1.4 ± 0.6 (SD) to 3.2 ± 1.8 mm Hg during isoprenaline (p < 0.05) and decreased to 0.6 ± 0.5 during ischemic failure (p < 0.01). The pressure gradient correlated positively with the time constant of isovolumic relaxation (tau) (r = 0.82) and negatively with LV end-systolic volume (ESV) (r = –0.77). Volume loading increased LA pressure, tau, and ESV, but caused no significant change in LVP_mitral-apex. At baseline and during isoprenaline, tau was shorter (p < 0.05) at the apex than at the base. When the mitral to apical gradient approached zero, filling velocities were directed toward the LV outflow tract, and a pressure gradient was established between the apex and subaortic region.

CONCLUSIONS: Changes in LVP_mitral-apex induced by inotropic stimuli, loading, and ischemia appeared to reflect dependency of the pressure gradient on the rate of relaxation, ESV, and LA pressure. Regional differences in the rate of relaxation may also contribute to intraventricular pressure gradients. These findings have implications for how to interpret intraventricular filling in a clinical context.

Abbreviations and Acronyms   CMD   color M-mode Doppler echocardiography   ESV   end-systolic volume   LA   left atrium or atrial   LV   left ventricular   dP/dtmin   minimal first derivative of left ventricular pressure   LAP   left atrial pressure   LVP   left ventricular pressure   tau   time constant of isovolumic left ventricular relaxation

This article has been cited by other articles:

				M. Tumkosit, C. G. Martin, E. Bayram, T. M. Morgan, K. S. Lane, P. Rerkpattanapipat, C. A. Hamilton, K. M. Link, and W. G. Hundley Left Ventricular Spherical Remodeling and Apical Myocardial Relaxation: Cardiovascular MR Imaging Measurement of Myocardial Segments Radiology, August 1, 2007; 244(2): 411 - 418. [Abstract] [Full Text] [PDF]

				J. Mizuno, S. Mohri, J. Shimizu, S. Suzuki, T. Mikane, J. Araki, H. Matsubara, T. Morita, K. Hanaoka, and H. Suga Starling-effect-independent lusitropism index in canine left ventricle: logistic time constant. Anesth. Analg., April 1, 2006; 102(4): 1032 - 1039. [Abstract] [Full Text] [PDF]

				Z. B. Popovic, A. Prasad, M. J. Garcia, A. Arbab-Zadeh, A. Borowski, E. Dijk, N. L. Greenberg, B. D. Levine, and J. D. Thomas Relationship among diastolic intraventricular pressure gradients, relaxation, and preload: impact of age and fitness Am J Physiol Heart Circ Physiol, April 1, 2006; 290(4): H1454 - H1459. [Abstract] [Full Text] [PDF]

				J. K. Oh, L. Hatle, A. J. Tajik, and W. C. Little Diastolic Heart Failure Can Be Diagnosed by Comprehensive Two-Dimensional and Doppler Echocardiography J. Am. Coll. Cardiol., February 7, 2006; 47(3): 500 - 506. [Abstract] [Full Text] [PDF]

				R. Yotti, J. Bermejo, J. C. Antoranz, J. L. Rojo-Alvarez, C. Allue, J. Silva, M. M. Desco, M. Moreno, and M. A. Garcia-Fernandez Noninvasive assessment of ejection intraventricular pressure gradients J. Am. Coll. Cardiol., May 5, 2004; 43(9): 1654 - 1662. [Abstract] [Full Text] [PDF]

				A. Pasipoularides, M. Shu, A. Shah, A. Tucconi, and D. D. Glower RV instantaneous intraventricular diastolic pressure and velocity distributions in normal and volume overload awake dog disease models Am J Physiol Heart Circ Physiol, November 1, 2003; 285(5): H1956 - H1965. [Abstract] [Full Text] [PDF]

				A. Pasipoularides, M. Shu, A. Shah, M. S. Womack, and D. D. Glower Diastolic right ventricular filling vortex in normal and volume overload states Am J Physiol Heart Circ Physiol, April 1, 2003; 284(4): H1064 - H1072. [Abstract] [Full Text] [PDF]