People and pets alike can have heart issues. Some are congenital, meaning that the patient was born with the abnormality, while others are acquired over the course of time. Cardiac problems can certainly lead to trouble and are something to be aware of.

Some, although not all, cardiac problems cause changes that can be heard when a stethoscope is used. Heart murmurs in pets are one of these changes. Thankfully, the doctors at Carriage Hills Animal Hospital have the beat on just what to do when one of these abnormal sounds is heard.

Things that Go Bump

No matter your species, that characteristic “lub-dub” sound that we associate with a heart beating is pretty spot on. We diagnose a pet as having a heart murmur when an additional sound is added to that rhythmic thumping.

Anything that causes a disruption or adds turbulence to the flow of blood within the heart can result in a murmur. Because the heart contains four separate chambers and four essential valves that help to direct blood flow, heart murmurs in pets may have several different sources.

Some of the more common causes of heart murmurs in pets include:

  • Heart valve leakage
  • Thickened heart valve
  • Hole or defect in the heart walls
  • Anemia or low blood protein (more watery blood leads to turbulent blood flow)
  • An abnormality in the large vessels associated with the heart (such as narrowing of the pulmonary artery)

Grading Heart Murmurs in Pets

If we auscultate a murmur when examining your pet, the next step is to try to characterize the murmur. This helps us to hone in on potential causes for the abnormal sound and to monitor its progression over time.

Heart murmurs in pets may be systolic (during the “lub” portion of the heartbeat), diastolic (during the “dub” portion), or continuous (throughout the heartbeat).

We will also try to determine over which portion of the chest the murmur is most loudly heard, or the point of maximum intensity. This may help us to determine which portion of the heart is likely to be affected.

We will also typically grade a pet’s heart murmur. Murmurs are graded on a scale of one to six as follows:

  • Grade I – Very faint
  • Grade II – Soft murmur localized to one area
  • Grade III – Intermediate murmur that may radiate to other areas of the chest
  • Grade IV – Loud, radiating throughout chest
  • Grade V – Loud with palpable vibration of the chest
  • Grade VI – Loud and does not require the stethoscope to be on the chest wall to be heard

Because murmurs are graded by volume, their grade does not always correlate with severity. For instance, a loud grade IV murmur may have very little effect on the heart’s functionality, while a grade I murmur may be causing congestive heart failure.

Much Ado About Nothing

In reality, while we try to do our best to characterize a heart murmur with our stethoscopes, we need further diagnostics in order to understand the implications of heart murmurs in pets.

Testing, such as blood work and heartworm screening, are often important in determining the potential cause of a heart murmur. We also recommend ECG (heart tracing) to evaluate heart rhythm and radiographs (x-rays) to look at overall size and shape of the heart and its vessels.

Radiographs, however, do not allow us to look at the individual heart valves, chambers, and thickness of the cardiac muscle. For this, we rely on cardiac ultrasound (echocardiogram), which is often the best way to determine an ultimate diagnosis for cardiac murmurs.

Beyond diagnosing their source, many heart murmurs do not require any special treatment other than monitoring. It is important that pets with a heart murmur receive proactive heart care, including excellent dental care, parasite prevention, and a good nutritional program with omega-3 fatty acids.

Pets who have an enlarged cardiac silhouette, but no evidence of heart failure, may be started on medications to help preserve heart function in an attempt to stave off further problems.

Of course, our patients who have problems resulting from their murmurs will need further therapy to help their heart to function as efficiently as possible. Having an accurate diagnosis can tailor our treatment more specifically.

Heart murmurs in pets are a common indicator that something may be impacting the cardiovascular system. Thankfully, we are able to find out exactly what and how serious it may be with a little investigation. Please let us know right away if you suspect your pet may have heart issues. Cardiac problems are definitely something we don’t want to wait to evaluate!