Anesthetic Management for Interventional Cardiac Procedures

The cardiac cycle is divided into ventricular systole and diastole. Mechanical ventricular systole begins immediately after the QRS complex, with contraction of the ventricular myocardium and closure of the atrioventricular valves. Alpha-2 adrenergic agonists are the class of drug most widely used to provide profound, reliable sedation in mature horses for preanesthetic sedation and general restraint, and include xylazine, detomidine, romifidine, dexmedetomidine, and medetomidine. Benzodiazepines provide anesthetic benefits as centrally acting muscle relaxants with minimal cardiovascular effects. Guaifenesin is a centrally acting muscle relaxant, and is used similarly to benzodiazepines as an anesthetic adjunct in equine anesthesia. Ketamine is an N-methyl-D-aspartate antagonist that provides analgesia and dissociative anesthetic effects. Various cardiac output measurement techniques have been evaluated in horses and foals. Patent ductus arteriosus occurs infrequently in horses, either alone or in combination with other artery defects. Atrioventricular block (AVB) can be divided into two groups: physiologic AVB and advanced or pathologic AVB.