Electrocardiographic evaluation of cardiac activity in dogs with CHF

Abstract

An important pathogenetic link of the progression of chronic heart failure of various genesis is the development of arrhythmias. They significantly complicate the course of CHF, because they lead to decreased cardiac output and increased hypoxia. The aim of our study was to investigate and evaluate the electrical activity of the heart of dogs with CHF. The research was performed on the basis of the private veterinary center “Vetmed” (Lviv) in 2016–2017. The study included 36 dogs of different breeds, ages, sexes with symptoms of chronic heart failure. A standard six-lead electrocardiogram (ECG) was recorded in all dogs in the right lateral position using an electrocardiograph “Vet ECG Ve – 300” (speed 50mm/s, sensitivity of the device 1mV = 10 mm). The obtained data were compared with reference values, and also took into account the variation of individual indicators depending on body weight. According to the results of our study, it was found that the frequency of arrhythmias in dogs with CHF is 75.0 %, of which 8.3 % – life-threatening, 38.9 % of the examined animals needed treatment, and 27.8 % – annual ECG monitoring. The signs of remodeling processes are found in 63.9 % of sick dogs, signs of ischemia – in 25 % and only in 2.8 % of animals – ECG without changes. The structure of arrhythmia in dogs with CHF is dominated by sinus tachycardia (47.2 %), sinus bradycardia (8.3 %), ventricular arrhythmias (5.6 %), atrial fibrillation (5.6 %), ventricular tachycardia (2.8 %). Among conduction disorders, we register intraatrial blockade (13.9 %) and AV-blockade of the first degree (8.3 %). In 13.9 % of animals ECG signs of fibrosis, ischemia are combined with changes in the size of the heart chambers. The results of our study show that a significant number of dogs with CHF have arrhythmias and conduction disorders. In order to improve diagnosis and treatment, the prospect of further research is to establish an association between ECG and echocardiographic changes in dogs with CHF, which can be both a cause of CH and its consequence and a predictor of an unfavorable prognosis.