Question

Dogs may normally have a slight variation in heart rhythm, such that the heart rate increases slightly during inspiration and decreases slightly during expiration. This is called ______________, and it is a sign that a dog has normal cardiac function.

Answer 1

The fluctuation in heart rate corresponding with the breathing cycle in dogs is known as respiratory sinus arrhythmia, a sign of normal cardiac function and not to be confused with irregular heartbeats such as tachycardia or bradycardia.

Step-by-step explanation:

The slight variation in heart rhythm where the heart rate increases during inspiration and decreases during expiration in dogs is called respiratory sinus arrhythmia. This phenomenon is a normal aspect of cardiac function in dogs and reflects a healthy heart's response to the changes in thoracic pressure that occur with the breathing cycle. It is distinct from an arrhythmia, which refers to an irregular heartbeat that can be too fast (tachycardia) or too slow (bradycardia) and may sometimes lead to complications such as stroke or heart failure. The normal rhythmic beating of the heart, known as sinus rhythm, is regulated by the heart's natural pacemaker, the sinoatrial node. The heart rate can also be influenced by various factors, including the autonomic nervous system and hormonal changes from the endocrine system, which can affect the electrical impulses that cause the heart to contract.