The aim of this study was to determine the haemodynamic reaction of a heart in which the left lateral wall was bored with laser channels until cardio-vascular collapse. Four calves were selected for the study. Series of five channels were bored with a 1.75 mm diameter laser probe. Each series was followed by a break of three minutes at the end of which haemodynamic parameters were recorded. The evolution of these parameters then underwent linear regression analysis. Calculations were made according to the percentage of the total number of channels, in order to standardize the results between the animals. Respectively 150, 155, 270 and 285 channels were bored. In each case, all haemodynamic parameters dropped abruptly during the last series of channels. Central venous pressure, mean pulmonary artery pressure, wedge pressure, mean arterial pressure and cardiac output followed a linear regression slope which did not significantly differ from zero. Heart rate only increased progressively with a liner regression slope significantly different from zero. In this acute model, haemodynamic parameters, except heart rate, did not correlate to the extent of damage imposed on the left ventricle. Thus, the presence of haemodynamic stability does not exclude important myocardial damage in an acute situation. This can be found in a clinical setting.