A percutaneous approach to cardiac haemodynamics in anaesthetised rats.

Established methods for evaluating cardiac function in small animals involve surgical manoeuvres. We describe a method for evaluating left ventricular volume (LVV) and pressure (LVP) in anaesthetised adult rats. Under fluoroscopic control a 23 G needle was inserted into the left ventricular cavity of anaesthetised normotensive WKY rats. LVV was determined by biplane angiography and LVP was measured directly. Surface electrocardiograms were recorded throughout the procedure. In 8 animals the study was repeated three times, one week apart. Animals were then sacrificed and tissues harvested for histological examination. In 8 rats, the technique was found to be reproducible and there was no evidence of functional (ECG) or pathological myocardial damage following repeated measurements. In conclusion this technique provides a reproducible method of measuring LVV and LVP, allowing longitudinal haemodynamic studies in anaesthetised rats.