Abstract
Determination of left ventricular ejection fraction (LVEF) using in vivo imaging is the cardiac functional parameter most frequently employed in preclinical research. However, there is considerable conflict regarding the effects of anesthetic agents on LVEF. This study aimed at assessing the effects of various anesthetic agents on LVEF in hamsters using transthoracic echocardiography. Twelve female hamsters were submitted to echocardiography imaging separated by 1-week intervals under the following conditions: 1) conscious animals, 2) animals anesthetized with isoflurane (inhaled ISO, 3 L/min), 3) animals anesthetized with thiopental (TP, 50 mg/kg, intraperitoneal), and 4) animals anesthetized with 100 mg/kg ketamine plus 10 mg/kg xylazine injected intramuscularly (K/X). LVEF obtained under the effect of anesthetics (ISO=62.2±3.1%, TP=66.2±2.7% and K/X=75.8±1.6%) was significantly lower than that obtained in conscious animals (87.5±1.7%, P<0.0001). The K/X combination elicited significantly higher LVEF values compared to ISO (P<0.001) and TP (P<0.05). K/X was associated with a lower dispersion of individual LVEF values compared to the other anesthetics. Under K/X, the left ventricular end diastolic diameter (LVdD) was increased (0.60±0.01 cm) compared to conscious animals (0.41±0.02 cm), ISO (0.51±0.02 cm), and TP (0.55±0.01 cm), P<0.0001. The heart rate observed with K/X was significantly lower than in the remaining conditions. These results indicate that the K/X combination may be the best anesthetic option for the in vivo assessment of cardiac systolic function in hamsters, being associated with a lower LVEF reduction compared to the other agents and showing values closer to those of conscious animals with a lower dispersion of results.
Highlights
Experimental models of heart disease employing small animals such as rats, mice, rabbits and hamsters have been increasingly used to study the physiopathogenic mechanisms of diseases and to test the effect of new drugs [1]
We used echocardiography to assess left ventricle (LV) function in a group of animals assessed in the conscious state and submitted to commonly employed anesthetic agents
The main results showed that the use of any of the tested anesthetic agents induced a reduction of left ventricle ejection fraction (LVEF) compared to the same animals in the conscious state
Summary
Experimental models of heart disease employing small animals such as rats, mice, rabbits and hamsters have been increasingly used to study the physiopathogenic mechanisms of diseases and to test the effect of new drugs [1]. In parallel to the expansion of areas of interest in preclinical research, advances of in vivo cardiac imaging [4,5,6,7,8,9] have permitted noninvasive assessment of cardiac structure and function in a reproducible and satisfactory manner. In view of its practicality, low cost and wide availability, echocardiography is the imaging method most frequently used [10], permitting the sequential assessment of morphological remodeling parameters and of systolic and diastolic left ventricular function [11]. Among the parameters that can be measured by echocardiography, the left ventricle ejection fraction (LVEF) is the most frequently used to determine left ventricle (LV) systolic function both in the preclinical [12] and clinical scenarios [13].
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Schedule a callMore From: Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas
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