Top 3 anatomy and physiology facts about a canine heart

Despite being a different species, dogs share many anatomical similarities with humans. In fact, the existing differences between the canine and human cardiovascular systems are relatively subtle.

Here are the top 3 facts about canine cardiovascular systems and how they differ from humans;

Fact 1: Leading cardiac disease in dogs

It’s estimated that more than 650,000 people die from cardiovascular diseases every year in the United States. Heart disease continues to be a leading cause of death not only in humans but also in animals. According to Pet Health Network, 7.8 million dogs in the United States are reported to have cardiovascular disease. This accounts for 10 percent of all dogs in the country.

Unknowingly to many people, there are clinical differences between cardiovascular diseases in dogs and humans. 

In humans, coronary artery disease is one of the most common heart diseases. It’s a condition in which coronary arteries fail to supply enough blood and oxygen to the heart due to cholesterol deposits built up in the wall of the arteries. Meanwhile, in dogs, mitral valve disease (a condition in which valves of left heart chambers can’t close fully) and dilated cardiomyopathy (when the heart can’t pump blood efficiently) is the most common disease. 

Fact 2: Heart rates

Canine heart rates are often irregular. The heartbeats in a healthy dog increase during inhalation and decrease at the exhalation phase. While a human heart beats 60-100 times per minute, an average-sized dog’s heart beats at a slightly faster rate, 60-120 times per minute. A smaller dog would have a heart rate of 120-160 times per minute.

Clinically examining the heart rates, scientists find that the change in heartbeats during canine breathing (inhalation and exhalation) doesn’t affect their life quality or expectancy. 

Fact 3: Anatomical differences

According to a comparative anatomy analysis published by the University of Minnesota, there are several subtle differences between canine and human cardiovascular anatomy. One of the most visible anatomical distinctions is how the canine vena cava are situated; they enter the heart perpendicular to one another, while the human superior vena cava and inferior vena cava are in line with each other. The location of fossa ovalis in dogs is also different. It’s located more caudally than it’s in the human heart. In addition, the coronary sinus ostium of the human heart is partly shielded by the Thebesian valve – a trait that doesn’t apply to the canine heart.

Also, the number of pulmonary veins differs in a canine heart compared to the human one. Specifically, a human heart has four or five pulmonary veins, while a dog heart has four to eight pulmonary veins that return blood to the left atrium. 

Take a look at the two videos below to understand the anatomical differences between a canine vs. a human heart.

References: University of Minnesota | Comparative Anatomy Tutorial

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