Influence of Temperature on Development of Rigor Mortis in Dog Hearts

The effect of temperature (1°C to 50°C) on the onset and maximal development of rigor mortis in dog hearts was studied systematically under static conditions. Excised hearts were submerged in Ringer's solution so that the ventricle could assume an elastic equilibrium state. This was characterized by zero transmural pressure and the presence of a certain volume in the ventricle. Pressure-volume curves were obtained in 29 experiments by removal as well as by addition of fluid. The pressure-volume relations were the same at all temperatures prior to the onset of rigor mortis. The criterion for the beginning of rigor mortis was the first change in pressure-volume relations and for maximum rigor the constancy of the attained relations. The shortest interval between cessation of the circulation and the beginning of rigor mortis was 25 minutes at 37°C, and three hours at 10°C. These measurements provide data defining the minimal period during which pressure-volume determinations can be made without post mortem alterations. The phenomenon of “primary dilatation” was observed irrespective of a withdrawal or an addition of fluid to the ventricle. The weight gain of the quiescent ventricle in Ringer's solution was determined until autolysis began and was found to be 5% during the first five hours at all temperatures ranging from 5°C to 45°C.