During a routine visit to the vet, the doctor will use a stethoscope to listen to your Chihuahua's heart. This test ensures that the heart is making expected sounds and that there are no abnormal sounds, which could indicate that there is a heart condition or disease. 

A heart murmur is one such abnormal sound that may indicate heart trouble, such as valve abnormalities, endocarditis, or narrowing of arteries. 

While not a disease or condition in itself, a heart murmur in Chihuahuas is a warning sign that requires further investigation.

A heart murmur can be a serious condition, especially when it comes to cute Chihuahuas. A heart murmur is a sound that is made by the heart, commonly described as a whooshing or swishing sound. It is due to the abnormal flow of blood within the heart, most commonly caused by a structural defect. 

For Chihuahuas, heart murmurs are a common health concern due to their small size and predisposition for heart problems. It is important for Chihuahua owners to be aware of the signs and symptoms of a heart murmur and to discuss with their veterinarian the best course of action for managing and treating this condition.

Your Chihuahua's symptoms with a heart murmur are contingent on their underlying cardiac condition. Common symptoms of heart disease and disorders include:

- abnormal heartbeat or fast pulse

- persistent cough and hacking

- panting excessively while at rest

- low energy and appetite loss

- fainting or collapsing

- the gums and/or tongue have a bluish color.

- severe water retention

Chihuahuas can develop a heart murmur from various conditions and diseases. Typically, Chihuahuas experience a leaky mitral valve in their heart which hinders blood flow from the left atrium to the left ventricle. 

During their aging process, the mitral valve tends to deteriorate and consequently, blood leaks backwards which leads to chronic valve disease, degenerative mitral valve disease, or endocardiosis.

When a veterinarian listens to your Chihuahua's heart, they assess the murmur's intensity, timing, and location. The murmur will be graded using a scale since not all heart murmurs sound the same.

Grade 1: A barely audible heart murmur, which is the least serious type.

Grade 2: A gentle whisper, audibly detectable with a stethoscope.

Grade 3: The sound level is moderate and spreads to multiple areas.

Grade 4: You can hear a loud murmur in both sides of the chest.

Grade 5: Loud murmuring noise.

Grade 6: The most severe kind of heart murmur is a loud one that can be felt by placing a hand on the Chihuahua's chest wall.

There are three types of heart murmurs in Chihuahuas: systolic, diastolic, and continuous.

Systolic Murmur: Heart murmurs that occur during the heart's contraction phase are known as systolic murmurs. A leaky mitral valve, which is the valve connecting the heart's left upper and lower chambers, is the most common cause. 

Pulmonic stenosis or subaortic stenosis, both of which obstruct blood flow by narrowing the blood vessel, are less frequent sources of systolic murmurs.

Chihuahuas rarely develop diastolic murmurs. However, if they do, aortic insufficiency is the usual culprit. This condition arises from a leaky aortic valve that fails to shut properly.

A continuous murmur is typically due to patent ductus arteriosus (PDA), a condition where a large blood vessel - the ductus arteriosus - fails to close shortly after birth. 

This is the most common congenital defect in Chihuahuas.

Heart murmur treatment for Chihuahuas varies based on the underlying cause. If the murmur is beginning, no treatment is necessary. However, follow-up appointments with your vet will be required to ensure resolution. 

Murmurs caused by cardiac disease or defect may require medication, surgery, or a specialized diet. Monitoring visits with your vet every 6 months are necessary at a minimum and may require further testing depending on your Chihuahua's condition. 

The outlook for a heart murmur hinges on its root cause and can range from optimistic to grim. Innocent murmurs that need no treatment usually have a favorable prognosis. Heart murmurs caused by non-cardiac illness or a treatable functional issue might dissipate with time.

Chihuahuas with a leaky mitral valve can benefit from long-term medication, which could prolong their lives or enhance their quality of life. The prognosis for dilated cardiomyopathy in Chihuahuas varies - if the Chihuahua already shows heart failure symptoms, the outlook is sadly unfavorable.

Chihuahuas born with heart defects have differing outcomes, depending on whether or not the defect can be surgically corrected. However, when surgery is successful, the prognosis is generally quite positive.

Also read:
Chihuahua Congestive Heart Failure: the guide