The effects of anesthetic drug choice on heart rate variability and echocardiography parameters in cats

Abstract

Abstract Heart rate variability is one of the assessments for cardiovascular risk during general anesthesia. The aims of this study were to assess the effects of an anesthetic drug on heart rate and heart rate variability (HRV) in cats and to provide the information for clinical applications. Twenty-four healthy client-owned cats of various breeds, 12 females and 12 males scheduled for elective surgery, were enrolled in this study. The cats were premedicated and induced with 4 protocols: protocol 1, diazepam (0.3 mg/kg) and propofol (3 mg/kg); protocol 2, diazepam (0.3 mg/kg) and alfaxalone (3 mg/kg); protocol 3, diazepam (0.3 mg/kg) and ketamine (5 mg/kg); and protocol 4, xylazine (1 mg/kg) and tiletamine/zolazepam (Zoletil) (5 mg/kg). The heart rate and heart rate variability of the 24 cats were collected before and at least 1 hour after administering the anesthetic drugs. Echocardiography was performed to evaluate heart function. Doppler was used to obtain the mean blood pressure. After anesthetic drug administration, higher heart rates were found in cats premedicated and induced with alfaxalone (p = 0.045) than in the other protocols, and the lowest heart rate (HR) values were found in cats in protocol 4 using xylazine and Zoletil. The HRV low frequency (LF) and high frequency (HF) power ratios increase in all protocols except for cats premedicated and intubation with propofol. The standard deviation of the normal sinus beats (SDNN) was higher in cats premedicated and induced with ketamine than in other anesthetic protocols (p = 0.015). An increase in sympathetic activity and reduced heart rate variability is associated with high blood pressure and left atrial dimension. The percentage of fractional shortening (FS) decreased in cats premedicated with ketamine. This study demonstrated that an anesthetic protocol using diazepam and propofol preserved cardiovascular function and was safe to use for surgeries in cats.