title: Left ventricular endocardial and epicardial strain changes with apical myocardial ischemia in an open-chest porcine model.
abstract: Early detection of acute myocardial ischemia is critical to prevent permanent myocardial damage. The impact of apical ischemia on global left ventricular (LV) function can be difficult to characterize using traditional volume-based echocardiography measures. Myocardial strain imaging is a sensitive, quantitative marker of myocardial deformation that can measure ventricular function. Recent advances allow layer-specific measurement of endo- and epicardial strain, enhancing the ability to evaluate myocardial ischemia. This study investigates the effects of apical ischemia on LV function using epi- and endocardial strain. We hypothesize that myocardial strain will identify changes in regional and global myocardial function associated with focal apical ischemia as compared to ejection fraction (EF), and that longitudinal strain will be a better indicator of myocardial dysfunction compared to circumferential or radial strain. In a porcine model (n = 9), acute ischemia was induced by left anterior descending coronary artery occlusion. Echocardiograms were performed at baseline, during 15-min ischemia, and after reperfusion. Global longitudinal strain decreased with acute focal ischemia of the left ventricular apical region (baseline: -16.4% vs. ischemia: -12.2%; P = 0.010), with no change observed in global circumferential and radial strain or EF Both endocardial and epicardial longitudinal strain decreased by 68% (P < 0.001) in the ischemic and peri-ischemic zone, while circumferential and radial strain only decreased in endocardium of the ischemic zone. Longitudinal strain was more sensitive to ischemia, being able to detect changes in global LV function and thus may confer clinical diagnostic advantage in the evaluation of acute LV apical ischemia.
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Howard-Quijano
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Melissa
authors.initials: M
authors.lastname: McCabe
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Alexander
authors.initials: A
authors.lastname: Cheng
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamakawa
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Einat
authors.initials: E
authors.lastname: Mazor
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Scovotti
authors.affiliation: Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, UCLA Health System, Los Angeles, California amahajan@mednet.ucla.edu.
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001794:Blood Pressure; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods; D006339:Heart Rate; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D013552:Swine; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: Echocardiography; ischemia; left ventricular function; strain