title: Quantification of left ventricular twisting mechanics by velocity vector imaging in an animal model of pericardial adhesions.
abstract: Diagnosis of constrictive pericarditis remains clinically challenging. Untwisting of the left ventricle (LV) is essential for normal LV diastolic function. Echocardiography is able to measure LV twisting mechanics. We designed an animal model of constrictive pericarditis to determine how pericardial-epicardial adhesions impair LV twisting mechanics. In eight open-chest pigs, the heart was exposed while preserving the pericardium. We simulated early constrictive pericarditis by pericardial constriction and patchy adhesions induced with instant glue and pericardial-epicardial stitches. Using Velocity Vector Imaging (VVI), LV magnitudes of twisting and untwisting were measured along with hemodynamic data at baseline and after the experimental intervention. Significant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. Magnitude of LV untwisting rate decreased from -80+/-23 degrees /s to -26+/-10 degrees /s (p=0.0009). LV twisting rate dropped from 78+/-20 degrees /s to 40+/-8 degrees /s (p=0.0039) and LV twist magnitude decreased from 9+/-2 degrees to 5+/-2 degrees (p=0.0081). Patchy pericardial adhesions are associated with reductions in LV untwisting rate and twisting magnitude, consistent with a negative impact of constrictive pericarditis on systolic and diastolic function. Impairments in LV twisting mechanics may have a diagnostic role in the detection of early stages of constrictive pericarditis.
authors.affiliation: Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, AZ 85259, USA.
authors.forename: Panupong
authors.initials: P
authors.lastname: Jiamsripong
authors.forename: Mohsen S
authors.initials: MS
authors.lastname: Alharthi
authors.forename: Anna M
authors.initials: AM
authors.lastname: Calleja
authors.forename: Eileen M
authors.initials: EM
authors.lastname: McMahon
authors.forename: Farouk
authors.initials: F
authors.lastname: Mookadam
authors.forename: Bijoy K
authors.initials: BK
authors.lastname: Khandheria
authors.forename: Marek
authors.initials: M
authors.lastname: Belohlavek
mesh_terms: D000465:Algorithms; D000818:Animals; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010493:Pericarditis / Q000150:complications* / Q000000981:diagnostic imaging*; D010496:Pericardium / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D000267:Tissue Adhesions / Q000000981:diagnostic imaging; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000000981:diagnostic imaging*