The Use of Anti-Arrhythmic Drugs vs. Electrical Cardioversion to Treat Tachyarrhythmias in the Canine and Feline Patient

摘要

When a canine or feline patient with congenital or acquired heart disease presents to a veterinary hospital with a serious disturbance of their cardiac conduction system resulting in an abnormally high heart rate and rhythm, correct diagnosis and treatment relies on the ability to perform a diagnostic quality electrocardiogram (ECG) for interpretation. Many cases are in need of immediate triage, such as the hemodynamically unstable patient with sustained runs of ventricular tachycardia and "R on T" complexes which can progress to ventricular fibrillation and cardiac arrest. Sustained runs of supraventricular tachycardia (SVT) or high heart rate atrial fibrillation (AF) should also be treated as soon as possible, but are not as life-threatening. A canine patient with lone A-fib presents with the arrhythmia, but not the rapid rate, so there is more time to make a treatment plan. The goals for treating a tachyarrhythmia are to lower heart rate and try to correct the rhythm in order to decrease workload on the heart muscle, improve cardiac output and make the patient feel better. If the patient is unresponsive to administration of antiarrhythmic drugs, in some cases, another option is to deliver a transthoracic electrical shock to the heart in order to restore a normal rate and rhythm. This can be performed as an emergency procedure, or as a planned outpatient procedure, depending on the type of tachyarrhythmia.