Thyroid hormones concentrations and ECG picture in the dog

Area of Science:

• Veterinary Medicine
• Endocrinology
• Cardiology

Background:

• Thyroid gland disorders are common endocrine issues in dogs.
• Hypothyroidism and hyperthyroidism can negatively affect the cardiovascular system, potentially causing arrhythmias.
• Evaluating thyroid activity's impact on canine ECGs is crucial for understanding cardiac disturbances.

Purpose of the Study:

• To assess the influence of thyroid gland activity on the electrocardiogram (ECG) in dogs.
• To compare ECG findings in healthy dogs, dogs with hypothyroidism, and dogs with cardiac insufficiency due to mitral valve endocardiosis.

Main Methods:

• The study involved 38 dogs divided into three groups: healthy controls, dogs with cardiac insufficiency, and dogs with hypothyroidism.
• Clinical examinations included history, physical, cardiological assessments (ECG, heart USG), and laboratory tests (lipids, thyroid hormones T3, T4, FT4).

Main Results:

• Thyroid activity significantly influences the ECG in dogs.
• Hypothyroidism was associated with decreased sino-atrial node activity and a slower heart rate.
• Dogs with hypothyroidism exhibited reduced intra-cardiac conduction, evidenced by prolonged P wave, QRS complex, and QT interval on ECG.

Conclusions:

• Thyroid dysfunction, particularly hypothyroidism, demonstrably alters cardiac electrical activity in dogs.
• ECG analysis is a valuable tool for detecting cardiac changes associated with thyroid disorders in canine patients.
• These findings highlight the importance of considering thyroid status in the diagnosis and management of canine heart disease.