The effects of chronic exposure to carbon monoxide on the cardiovascular and hematologic systems in dogs with experimental myocardial infarction

12 normal and 12 infarcted animals were continuously exposed (23 hrs/day) to 115 mg/cu m carbon monoxide for 14 weeks; 6 normal and 6 infarcted animals were allowed to breath ambient air. Blood was drawn weekly for hematologic studies, and the ECG was also recorded. The general well being of the animals was assessed by alertness, food and water intake, stool consistency, respiratory and heart rates, body weight, and rectal temperature. At the conclusion of the exposure period the animals were sacrificed for gross and microscopic observation of the heart and other tissues. Throughout the exposure period the animals remained in clinically good health. No obvious untoward signs were noted which could be interpreted as carbon monoxide induced: serum enzymes (CPK, GOT, LDH) or ECG were not characteristically altered; hematologic parameters (Hct, Hb, WBC, RBC, platelets, MCH, MCHC, MCV, and fibrin split products) did not change significantly. COHb averaged 14% in animals exposed to carbon monoxide, and 1.3% in air breathing animals. © 1972 Springer-Verlag