Help! My Pet Has A Heart Murmur

So your pet is diagnosed with a heart murmur. You try to process. Your first thoughts may go to someone you know with a heart murmur or something you heard on a tv medical drama. Then comes the questions. What does this mean? How did I miss this? What do I do? Can we fix this? Is this the end? Slow down there cowboy (or cowgirl). Not all heart murmurs are created equal and there are ways to manage them. Many patients with murmurs can live long fulfilling lives.

Heart murmurs are the most common symptom of a heart abnormality and are usually picked up on routine physical exams. Small breed dogs and older cats are more likely to be diagnosed with a heart murmur than other demographics. “Innocent heart murmurs” can be found in 28% of puppies under 6 months old and often disappear after 6 months of age.This is why it is important for your pet to have an annual examination with a vet as this condition can develop and worsen over time.

All this talk of murmurs and we still haven’t said what the heck they are! Hold your horses cowboy (or cowgirl), we’re getting there. A normal heart beat should have two quick, clear, and distinct sounds when listening with a stethoscope. Lub-dub…lub-dub…lub-dub. These two sounds are created by the valves inside the heart opening and closing. Heart valves prevent backflow and allow blood to be pumped through the four chambers of the heart and into the rest of the body. Heart murmurs occur when one or multiple valves malfunction, preventing them from fully snapping shut. As a result blood backflows through the valve(s) as the heart pumps. This backflow creates an audible “whoosh” over the normal lub dub sounds when heard through a stethoscope. Other causes of heart murmurs may include an enlarged heart or shunts within the heart. As heart function declines, the heart cannot effectively pump blood throughout the body, causing blood to pool in the lungs. This condition is called congestive heart failure (CHF). Clear as mud? I thought so.

Murmurs are graded from one to six with grade one being the least severe (barely audible) and grade six being the most severe (can be felt by hand). Most patients with low grade murmurs do not show any symptoms at all. As murmurs develop into CHF, patients may experience exercise intolerance, coughing (especially when excited), and collapse. Luckily, there are things we can do to help.

Diuretics (colloquially called “water pills”) such as furosemide help draw off excess fluid from the lungs allowing patients to breathe easier. Unfortunately, this excess fluid has to go somewhere, resulting in frequent urination and drinking. Vasodilators, such as enalapril, are another medication used to control the effects of heart murmurs. As the name suggests, vasodilators dilate blood vessels resulting in a decrease in blood pressure and increased cardiac output. Significant side effects such as kidney damage can occur if not monitored closely. Bloodwork is always recommended. While not a cure, a patient's quality of life often greatly improves after starting these meds.

So your pet is diagnosed with a heart murmur. You now know what it is and how to treat it. There is no need to panic. Hopefully there are many good years to come.