Performance Of Echocardiographic Parameters In Sequential Monitoring Of Left Ventricular Function In An Animal Model Of Acute Heart Failure

Introduction: Numerous newer parameters have been established for sensitive and reproducible evaluation of left ventricular (LV) dysfunction. We assessed the performance of these parameters in sequential monitoring of LV function in an animal model of controllable drug-induced LV dysfunction. Methods: To establish predictable aggravating LV dysfunction, seven male beagle dogs were anesthetized and received intermittent injection of esmolol and propofol of gradually increasing dosage. Parameters reflecting LV function were measured after each drug infusion. These included LV ejection fraction (LVEF) measured by both two-dimensional (2D) and three-dimensional (3D) echocardiography, Tei index, ratio of early diastolic transmitral flow velocity to early diastolic mitral annular velocity (E/e') and 2D strain-derived parameters. Changes in these parameters over time were compared with the baseline value. Results: Changes in 2D and 3D LVEF were observed after infusion with propofol (5 mg/kg) and esmolol (3.5 mg/kg). Doppler-derived parameters including E/e' and the Tei index failed to detect LV dysfunction prior to 2D LVEF. Significant changes in 2D strains and strain rates (SRs) could be induced by relatively small anesthetic dosages (similar to 4 mg propofol/kg and 2.5 mg esmolol/kg). Strain-derived parameters were generally highly reproducible and longitudinal strain had the best intraobserver and interobserver reproducibility. Conclusions: The 2D strain parameters provide accurate identification of subclinical impairment of LV function earlier than all other echocardiographic indices. (Echocardiography 2010;27:1274-1281).