Measurements of left and right ventricular pressures and their derivatives by transcutaneous puncture in rats

Eighteen rats were anesthetized with xylazine/ketamine and placed in right lateral recumbency, and a small incision was made in the skin of the left hemithorax. A 21-gauge, 1-inch, short-beveled hypodermic needle, attached directly to a pressure transducer filled with degassed saline solution, was advanced through the incision into the left ventricle and then advanced through the septum into the right ventricle. High-fidelity tracings of right and left ventricular pressures and their derivatives were obtained through this approach in 13 rats. In 5 rats, measurements of right ventricular pressures were obtained by additional right ventricular puncture through the incision in the left hemithorax. Right and left ventricular pressures were recorded on single occasions in 18 rats, twice at 2-week intervals in 6 rats, and 3 times at 2-week intervals in 3 rats. Minimal hemopericardium was observed, but most rats had evidence of hemorrhage on the visceral pericardium. Left and right ventricular pressures can be measured rapidly, safely, and repeatedly in anesthetized rats by this method.