title: Effects of anesthesia on echocardiographic assessment of left ventricular structure and function in rats.
abstract: Echocardiography is an essential diagnostic tool for accurate noninvasive assessment of cardiac structure and function in vivo. However, the use of anesthetic agents during echocardiographic studies is associated with alterations in cardiac anatomical and functional parameters. We sought to systematically compare the effects of three commonly used anesthetic agents on echocardiographic measurements of left ventricular (LV) systolic and diastolic function, LV dimensions, and LV mass in rats. Adult male Fischer 344 rats underwent echocardiographic studies under pentobarbital (PB, 25 mg/kg i.p.) (group I, n = 25), inhaled isoflurane (ISF, 1.5%) (group II, n = 25),or ketamine/xylazine (K/X, 37 mg/kg ketamine and 7 mg/kg xylazine i.p.) (group III, n = 25) anesthesia in a cross-over design. Echocardiography was also performed in an additional group of unanesthetized conscious rats (group IV, n = 5). Postmortem studies were performed to validate echocardiographic assessment of LV dimension and mass. Rats in group I exhibited significantly higher LV ejection fraction, fractional shortening, fractional area change, velocity of circumferential fiber shortening corrected for heart rate, and heart rate as compared with groups II and III. LV end-diastolic volume, end-diastolic diameter, and cross-sectional area in diastole were significantly smaller in group I compared with groups II and III. Cardiac output was significantly lower in group III compared with groups I and II. Postmortem LV mass measurements correlated well with echocardiographic estimation of LV mass for all anesthetic agents, and the correlation was best with PB anesthesia. Limited echocardiographic data obtained in conscious rats were similar to those obtained under PB anesthesia. We conclude that compared with ISF and K/X anesthesia, PB anesthesia at a lower dose yields echocardiographic LV structural and functional data similar to those obtained in conscious rats. In addition, PB anesthesia also facilitates more accurate estimation of LV mass.
authors.affiliation: Institute of Molecular Cardiology, University of Louisville, KY 40292, USA.
authors.forename: Adam B
authors.initials: AB
authors.lastname: Stein
authors.forename: Sumit
authors.initials: S
authors.lastname: Tiwari
authors.forename: Paul
authors.initials: P
authors.lastname: Thomas
authors.forename: Greg
authors.initials: G
authors.lastname: Hunt
authors.forename: Cemil
authors.initials: C
authors.lastname: Levent
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Stoddard
authors.forename: Xian-Liang
authors.initials: XL
authors.lastname: Tang
authors.forename: Roberto
authors.initials: R
authors.lastname: Bolli
authors.forename: Buddhadeb
authors.initials: B
authors.lastname: Dawn
mesh_terms: D018681:Anesthetics, General / Q000494:pharmacology*; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D003971:Diastole / Q000187:drug effects; D015150:Echocardiography, Doppler / Q000187:drug effects*; D006321:Heart / Q000033:anatomy & histology / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000187:drug effects; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D007530:Isoflurane / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D013599:Systole / Q000187:drug effects; D016277:Ventricular Function, Left / Q000187:drug effects*; D014991:Xylazine / Q000494:pharmacology
chemical_list: D018681:Anesthetics, General; D006993:Hypnotics and Sedatives; D014991:Xylazine; D007649:Ketamine; D007530:Isoflurane; D010634:Phenobarbital