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Pulsed‐Wave Doppler Blood Flow Through the Pulmonary Trunk as a Valuable Method to Determine Cardiac Output Following Myocardial Infarction
Author(s) -
Platt Mathew J,
Huber Jason S,
Brunt Keith R,
Simpson Jeremy A
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.977.1
Subject(s) - cardiology , ventricle , medicine , cardiac output , myocardial infarction , stroke volume , doppler effect , blood flow , cardiac function curve , pulmonary trunk , trunk , hemodynamics , heart failure , aorta , physics , ejection fraction , ecology , astronomy , biology
Background Cardiac output (CO) is a valuable measure of cardiac function, both clinically and in small animal models of cardiac injury (e.g., myocardial infarction; MI). As the product of stroke volume and heart rate, CO can be estimated from cardiac volumes acquired from one (i.e., M‐Mode) and two (i.e., single plane ellipsoid formula) dimensional echocardiographic images of the left ventricle (LV). Critically, deformations of the LV following MI (e.g., non‐uniform composition/contractile properties) invalidate the mathematical assumptions imperative to the accurate estimation of CO. Thus, the purpose of this study was to determine if pulsed‐wave Doppler flow through the pulmonary trunk – a structure independent of the remodeling in the ischemic LV – provided an alternative, and more accurate, method to quantify forward CO following MI. Methods Variations in CO were induced either by transverse aortic constriction (TAC) or MI. CO was calculated from classical LV‐dependent methods (M‐Mode and the single‐plane ellipsoid 2D formula), pulsed‐wave Doppler through the pulmonary trunk (pulmonary flow), and intra‐thoracic flow probe. Results In healthy mice, all three echocardiography methods (M‐Mode, 2D and pulmonary flow) correlated well with flow‐probe derived CO as confirmed by Bland‐Altman analysis. In MI, only pulmonary flow demonstrated both accuracy and precision, retaining the expected positive bias and demonstrating <10mls/min range difference compared to the 20–25mls/min range for either LV‐dependent method. Pulmonary flow CO in MI also demonstrated reduced inter‐ and intra‐user variability, and both an improved internal and external agreement (correlation coefficients) when compared against either M‐Mode or 2D CO calculations. Conclusions Pulmonary flow CO calculated from pulsed‐wave Doppler through the pulmonary trunk was an improved method of estimating CO over LV‐dependent formulae following MI. There was also a significant correlation between pulmonary flow, M‐Mode and 2D measures in healthy and TAC mice, demonstrating pulmonary flow was a comparable estimation of CO in these non‐ischemic conditions. This is relevant in the continuing attempt to more accurately assess cardiac function and particularly, grade preclinical therapies for treating MI. Support or Funding Information This work was supported by the Canadian Institutes of Health Research grant (MOP 111159) to J.A. Simpson. J.A. Simpson is a New Investigator of the Heart and Stroke Foundation of Canada.