Wave Intensity Analysis of Left Atrial Mechanics and Energetics in Anesthetized Dogs.
From: Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Health Sciences Centre, Univ of Calgary, Calgary, Alberta, Canada.
American journal of physiology. Heart and circulatory physiology
- Publish Date: Mar 2007
- ISSN: 0363-6135
- Volume: 292
- Issue: 3
- Pages: H1533-40
- Medium: Print
- Language: English
- Citation (JAMA): Hobson Tracy N, Flewitt Jacqueline A, Belenkie Israel, et al. Wave Intensity Analysis of Left Atrial Mechanics and Energetics in Anesthetized Dogs.. Am. J. Physiol. Heart Circ. Physiol. Mar 2007;292:H1533-40
Abstract
The left atrium (LA) acts as a booster pump during late diastole, generating the Doppler transmitral A wave and contributing incrementally to left ventricular (LV) filling. However, after volume loading and in certain disease states, LA contraction fills the LV less effectively, and retrograde flow (i.e., the Doppler Ar wave) into the pulmonary veins increases. The purpose of this study was to provide an energetic analysis of LA contraction to clarify the mechanisms responsible for changes in forward and backward flow. Wave intensity analysis was performed at the mitral valve and a pulmonary vein orifice. As operative LV stiffness increased with progressive volume loading, the reflection coefficient (i.e., energy of reflected wave/energy of incident wave) also increased. This reflected wave decelerated the forward movement of blood through the mitral valve and was transmitted through the LA, accelerating retrograde blood flow in the pulmonary veins. Although total LA work increased with volume loading, the forward hydraulic work decreased and backward hydraulic work increased. Thus wave reflection due to increased LV stiffness accounts for the decrease in the A wave and the increase in the Ar wave measured by Doppler.
Mesh Headings (Keywords): Animals, Atrial Function, Left, Blood Pressure, Carotid Arteries, Dogs, Heart Atria, Myocardial Contraction, Pulmonary Veins, Ultrasonography, Doppler
Check for Full Text / PubMed Unique Identifier (PMID): 17114242
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.