Langendorff Perfused Heart
Cardiac function is dependent upon plethera of circulating, neural and mechanical influences. A classical method to examine the intrinsic properties of the heart is to use a controlled, isolated preparation originally developed by Oscar Langendorff. Since its original design, near the start of the last century, this preparation has undergone a number of enhancements, modifications and alterations to address a host of novel issues. The consummate review of the principals associated with this technique has been published by Neely and Neely and Rovetto. The history and numerous variations of this preparation has beeen recently reviewed by Sutherland and Hearse.
For our purposes, our preparation uses rat hearts mounted on a cannula, as shown above, and perfused with warm oxygenated buffer. The setup is also fitted with inline pressure transducers and a flow probe. The preparation is perfused at either a constant flow or a constant pressure. A microballoon, fitted upon the tip of another cannula is inserted into the left ventricle via an atrial wound, and the heart is paced.
The maximum rate of change in left ventricular pressure (dP/dt) is measured as an index of contractility.
The heart is perfused with different agents and the changes resistance (resistance = pressure/flow) are calculated. Also, changes in cardiac contractility can be plotted as a function of flow.