A small animal model for monitoring inotropic responses to cardiotonic agents

A method for evaluating potential cardiotonic agents in vivo has been developed in a small laboratory animal. In this study, right ventricular inotropic responses are measured in an anesthetized, closed-chested guinea pig using a pressure-sensitive transducer inserted into the right ventricle of the heart via the right jugular vein. dp/dt is used as an index of ventricular contractility. Agents known to have positive inotropic effects in other models were found to have similar effects using this new method. Some advantages of using such a model include: relatively rapid surgical preparation; use of less costly small animals; and the need for less compound for experimentation.