Eighteen adult rat hearts were studied by Langendorff's Technique under Krebs-Henseleit solution perfusion (90 ± 10 cm of H2O pressure, 36.5 ± 0.5°C temperature). Nine rats were assigned to two groups: Group I - control group and Group II - isoflurane group. Hearts in Group II were treated with isoflurane at 1.5%. After stabilization during 15 minutes, initial values were obtained (t0), the next parameters were registered over the following periods: 1, 2, 4, 6, 10 minutes, respectively. There were no statistically significant variations in systolic pressure nor in dp/dt (p > 0.05) in period t1 in both groups. An increase was observed in diastolic pressure, statistically significant in Group II (4.8 mmHg - t0 period; 12.8 mmHg - t1 period). There was a decrease in heart rate and increase in coronary flow in Group II, statistically significant(p < 0.05), one minute after drug infusion. The coronary flow decreased progressively in every recovery period (t2 t0 t5) in Group II (p < 0.05). During the same periods there were no statistically significant variations in Group I. Isoflurane increases coronary flow during its administration, decreasing it during the recovery periods; it decreases heart rate, increases diastolic pressure and shows evidence of myocardial contractility depression in isolated rat hearts.
Isoflurane; Anesthetics; Anesthetics; Myocardial contraction; Coronary circulation; Heart rate
