- Email: [email protected]
Effect of hypothermia on the heart rate, the arterial pressure and the electrocardiogram of the rat
Abstracts
and
Reviews
Selected Abstracts Crismon, J. M.: Effect of Hypothermia and the Electrocardiogram of the Rat.
on the Heart Rate, the Arterial Arch. Int. Med. 74: 235, 1944.
The effects of hypothermia on the heart rate, the arterial cardiogram of rats cooled to lethal levels were investigated.
pressure,
Pressure
and the electro-
Both the heart rate and the conduction of the cardiac impulse were slowed by reduction of the body temperature. The relationship of the heart rate to the body temperature was linear over the range from 15” to 35” C. (59” to 95” F.), with a Q0 of 2.14, and had a high positive correlation. The slowing of conduction in the heart was proprtional to the change in heart rate. During the reduction of body temperature. the arterial pressure increased as the shivering became maximal down to a rectal temperature of 29” C. (84.2” F.). Further reduction of temperature resulted in a decline of arterial pressure, at first gradual, until the temperature reached about 23” C. (73.4” F.), and then precipitous, as the temperature fell below 21” C. (69.8” F.). The relation between arterial pressure and heart rate became linear after the heart had slowed to about one-third the normal rate. Complete atrioventricular block was observed only after the arterial pressure had reached levels below 80 mm. of mercury. Abnormalities of the P wave and complete atrioventricular dissociation were the most striking features at low temperatures. The arrhythmias were of two types: sinoatrial block with shift of the pacemaker to other parts of the atria and finally the establishment of atrioventricular nodal rhythm and complete atrioventricular block. The first type was reversible by raising the body temperature slowly; the second may be corrected by administering artificial respiration, or may disappear when the temperature rises slowly during recovery. Respiratory arrest in hypothermic rats occurred only after had fallen below 70 mm. of mercury. The circulatory failure arrest was closely related to the degree of cardiac slowing.
the arterial pressure preceding respiratory
AUTHOR. Member, Arch.
S., Bruger, Path.
M., and
Oppenheim,
E.:
Experimental
Atherosclerosis.
38: 210, 1944.
Cholic or glycocholic acid fed 6th cholesterol to the rabbit increases the cholesterol contents of the whole blood and the aorta as compared with obtained following the ingestion of cholesterol alone. this
Dehydrocholic property.
acid,
hyodesoxycholic
acid,
and
desoxycholic
In two series of experiments in which desoxycholic were used, respectively, the latter was shown to augment the liver; the former was without effect in this regard. The panied
feeding of by increased
eholic acid, concentration
unlike that of of combined
acid the
acid
do
markedly the levels not
possess
and glycocholic acid cholesterol content of
any other bile acid tested, is aceom(ester) cholesterol in the whole blood.
AUTHORS. 409
and
Reviews
Selected Abstracts Crismon, J. M.: Effect of Hypothermia and the Electrocardiogram of the Rat.
on the Heart Rate, the Arterial Arch. Int. Med. 74: 235, 1944.
The effects of hypothermia on the heart rate, the arterial cardiogram of rats cooled to lethal levels were investigated.
pressure,
Pressure
and the electro-
Both the heart rate and the conduction of the cardiac impulse were slowed by reduction of the body temperature. The relationship of the heart rate to the body temperature was linear over the range from 15” to 35” C. (59” to 95” F.), with a Q0 of 2.14, and had a high positive correlation. The slowing of conduction in the heart was proprtional to the change in heart rate. During the reduction of body temperature. the arterial pressure increased as the shivering became maximal down to a rectal temperature of 29” C. (84.2” F.). Further reduction of temperature resulted in a decline of arterial pressure, at first gradual, until the temperature reached about 23” C. (73.4” F.), and then precipitous, as the temperature fell below 21” C. (69.8” F.). The relation between arterial pressure and heart rate became linear after the heart had slowed to about one-third the normal rate. Complete atrioventricular block was observed only after the arterial pressure had reached levels below 80 mm. of mercury. Abnormalities of the P wave and complete atrioventricular dissociation were the most striking features at low temperatures. The arrhythmias were of two types: sinoatrial block with shift of the pacemaker to other parts of the atria and finally the establishment of atrioventricular nodal rhythm and complete atrioventricular block. The first type was reversible by raising the body temperature slowly; the second may be corrected by administering artificial respiration, or may disappear when the temperature rises slowly during recovery. Respiratory arrest in hypothermic rats occurred only after had fallen below 70 mm. of mercury. The circulatory failure arrest was closely related to the degree of cardiac slowing.
the arterial pressure preceding respiratory
AUTHOR. Member, Arch.
S., Bruger, Path.
M., and
Oppenheim,
E.:
Experimental
Atherosclerosis.
38: 210, 1944.
Cholic or glycocholic acid fed 6th cholesterol to the rabbit increases the cholesterol contents of the whole blood and the aorta as compared with obtained following the ingestion of cholesterol alone. this
Dehydrocholic property.
acid,
hyodesoxycholic
acid,
and
desoxycholic
In two series of experiments in which desoxycholic were used, respectively, the latter was shown to augment the liver; the former was without effect in this regard. The panied
feeding of by increased
eholic acid, concentration
unlike that of of combined
acid the
acid
do
markedly the levels not
possess
and glycocholic acid cholesterol content of
any other bile acid tested, is aceom(ester) cholesterol in the whole blood.
AUTHORS. 409