title: Right ventricular free wall circumferential strain reflects graded elevation in acute right ventricular afterload.
abstract: This study was designed to evaluate the concurrent changes in the right ventricular free wall (RVFW) movement in experimentally induced, acute mild, moderate, and severe right ventricle (RV) afterload conditions. In 14 open-chest pigs (weight 43 +/- 4 kg) with preserved pericardia, acute mild (>35 and <50 mmHg), moderate (> or =50 and < or =60 mmHg), and severe (>60 mmHg) increases in RV systolic pressure (RVSP) were induced by constriction of the pulmonary artery. At each step, longitudinal, radial, and circumferential strains and strain rates were measured in both the RVFW and the interventricular septum. The mean RVSPs were 31.0 +/- 4.3 mmHg at baseline and 41.1 +/- 2.7 mmHg during mild, 52.7 +/- 3.4 mmHg during moderate, and 61.7 +/- 1.6 mmHg during severe afterload conditions. The RVFW circumferential strains showed significant differences among baseline, mild, moderate, and severe afterload conditions (-10.5 +/- 3.9, -8.3 +/- 3.3, -5.4 +/- 2.7, and -7.5 +/- 5.3%, respectively, P = 0.008) and had significant linear correlation with RVSP (r = 0.636, P < 0.001) if the severe condition was excluded. Decrease of the RVFW circumferential strain magnitude is the most distinct response in acute mild and moderate RV afterload that could aid in detection of clinical conditions associated with acutely increasing RV afterload.
authors.affiliation: Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Cho
authors.forename: Panupong
authors.initials: P
authors.lastname: Jiamsripong
authors.forename: Anna M
authors.initials: AM
authors.lastname: Calleja
authors.forename: Mohsen S
authors.initials: MS
authors.lastname: Alharthi
authors.forename: Eileen M
authors.initials: EM
authors.lastname: McMahon
authors.forename: Bijoy K
authors.initials: BK
authors.lastname: Khandheria
authors.forename: Marek
authors.initials: M
authors.lastname: Belohlavek
mesh_terms: D000818:Animals; D003250:Constriction; D004195:Disease Models, Animal; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008955:Models, Cardiovascular; D009200:Myocardial Contraction; D011651:Pulmonary Artery / Q000601:surgery; D012720:Severity of Illness Index; D013552:Swine; D014463:Ultrasonography; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right; D017725:Ventricular Pressure; D054088:Ventricular Septum / Q000503:physiopathology