Dobutamine stress echocardiography in healthy adult male rats

15 normal adult male Wistar rats were evaluated. Increasing doses of dobutamine were infused intravenously under continuous imaging of the heart by a 12 MHz ultrasound probe.Dobutamine stress echocardiography reduced gradually LV diastolic and systolic dimensions. Ejection fraction increased by a mean of +24% vs. baseline. Heart rate increased progressively without reaching a plateau. Changes in LV dimensions and ejection fraction reached a plateau after a mean of 4 minutes at a constant infusion rate.DSE can be easily performed in rats. The normal response is an increase in heart rate and ejection fraction and a decrease in LV dimensions. A plateau in echocardiographic measurements is obtained after 4 minutes of a constant infusion rate in most animals.Dobutamine stress echocardiography (DSE) is commonly used in clinical practice to investigate patients with a wide variety of cardiovascular diseases. DSE can be used for many purposes such as to seek myocardial ischemia, evaluate valvular diseases, measure myocardial viability and assess myocardial contractile reserve [1-8]. Improvements in cardiac ultrasound imaging devices in recent years have allowed investigators to use echocardiography in small animals with cardiac diseases such as rats and mice and obtain images of very good quality. Consequently, research groups are now routinely using cardiac ultrasound imaging not only to investigate large animals (such as dogs and pigs) but also small rodents. Dobutamine stress imaging has also emerged in those small animals. Investigators working with small animal models of cardiac diseases have been using dobutamine stimulation mostly to assess myocardial contractile reserve. Accurate interpretation of a stress test requires that the response of normal subjects to that test is well documented. However, there is currently no available data on the normal response to dobutamine stimulation of the hearts of rats and we do not know if they respond to DSE as humans do. Therefo