Influence of Temperature on Development of Rigor Mortis in Dog Hearts

Abstract

The effects of temperature on the development of rigor mortis in cardiac muscle have never been investigated systematically. Brecher and Kissen 1 found that pressure-volume characteristics of non-beating, submerged dog ventricles remained constant for at least 30 minutes following circulatory arrest at 35°C. Using similar methods, Griggs et al. 2 found this period to be approximately 80 minutes at 36°C and 300 minutes at 5°C. These and other related studies of rigor mortis 3 " 9 were not primarily directed at the effects of varying temperature under controlled conditions. We have therefore adapted the technique of Brecher and Kissen 1 to permit systematic investigation of tlie effects of temperature on the onset and development of rigor mortis in dog hearts. This study provides a background for future investigations in which the time limits for development of rigor mortis must be known.Methods The principle of the method is to establish an "elastic equilibrium" of the ventricles b}7 submerging the heart in Ringer's solution. The state of elastic equilibrium of a ventricle is characterized by zero transmural pressure. Under this condition there is always a certain volume of fluid in the freshly excised ventricle. Upon reducing the intraventricular volume, the transmural pressure becomes negative and upon fluid addition it becomes positive. This method lends itself to pressurevolume studies in which any stretch of the ventricular walls can be avoided. Since such stretch might affect the development of rigor mortis, half of the experiments were done with negative transmural pressures only and compared with the others From the in which both negative and positive transmural pressures were produced.Fifty-five mongrel dogs of various ages were used, 37 for studies on left ventricles, 18 for studies on right ventricles. Preceding these experiments, most of the animals had been employed in other studies which did not involve the cardiovascular system. The animals were anesthetized intravenously with sodium pentobarbital (30 mg/kg of body weight). Six minutes after the injection they were rapidly exsanguinated from a femoral artery. Four minutes after the beginning of exsanguination the removal of the heart from the pericardial sac was completed. The aorta and pulmonary artery were severed 5 cm from their origin and the systemic and pulmonary veins were divided at their entrance into the atria. The hearts were then rinsed in Ringer's solution and the aorta and pulmonary artery stumps were ligated. The experimental arrangement is shown in figure 1.A Tygon cannula (inner diameter 10 mm) was placed in the atrioventrieular orifice and secured by a ligature around the atrioventrieular groove. The hearts were submerged in Ringer's solution in a constant temperature bath. The bath could be adjusted to temperatures between 1°C and 50°C (± 0.25). The composition of the buffered Ringer's solution used was NaCl 0.9 g, KC1 0.03 g, CaCl 2 anhyd. 0.026 g, 3\ T aHCO 3 0.055 g, water to 100 ml 2 The ventricular cannula was connected via...

Volumes and Compliances Measured Simultaneously in the Right and Left Ventricles of the Dog

“…Such relationships previously reported are difficult to interpret, and are of uncertain relevance to conditions in vivo, because the effects of rigor mortis were not always considered and because in previous studies fluid was infused into only one ventricle at a time (1)(2)(3). In the present study we have found that volume-pressure relationships are highly dependent upon the state of filling of the contra-lateral chamber.…”

Ventricular Volume of Nonbeating Excised Dog Hearts in the State of Elastic Equilibrium

“…The heart was transferred to a constant temperature bath containing Ringer's solution at 10°C ± 0.25. From previous experiments (3,4) it is known that no important changes occur in the pressurevolume curve of excised canine ventricles for at least 3 hours at 10°C. The ventricular cannula was connected to a graduated burette, and the fluid levels of bath and burette equalized to establish zero transmural pressure across the ventricular wall.…”

“…The technique used for the present experiments is similar to that previously described (3). Dogs were anesthetized with pentobarbital (30 mg/kg body weight, iv) and rapidly exsanguinated.…”

“…suction. A graphic representation of the concept was previously published by Kolder et al (3). The purpose of the present study is to measure under controlled conditions the left and right ventricular volume in the state of elastic equilibrium and to relate the measured volumes to body weight, weight of both ventricles, and sex.…”

Right heart pressure does not equal pericardial pressure in the potassium chloride-arrested canine heart in situ.

“…First, we compared the pre-and post-pericardiectomy pressure-time curves graphically. Second, we analyzed the relative contribution of the pericardium to chamber pressures in both sides of the heart by selecting prepericardiectomy chamber pressures of interest: 1, 3, 5, 8, 11, and 15 mmHgintherightheartand2, 5,8,11,15,20, and 25 mm Hg in the left heart. We then computed the pressure drop caused by pericardiectomy at the volumes obtained at these prepericardiectomy pressures.…”