Heart Disease in Dogs | Rochester MN

What is a heart murmur?

A heart murmur is an abnormality heard with a stethoscope when listening to the heartbeat. Murmurs are graded on a 1-6 scale. A murmur rated a level of ‘1’ indicates a mild, soft change. Anything ranging from ‘4’ to ‘6’ signifies a loud, serious abnormality. Heart murmurs can reflect heart valve changes or rare congenital abnormalities in the heart structure.

The presence of a heart murmur does not always indicate disease. X-rays, ultrasound, or clinical signs of heart disease (coughing, weight loss, exercise intolerance) can help determine the presence or severity of disease.

Ways to evaluate heart disease:

1. Chest X-rays – detect fluid buildup in the lungs and show general heart size
2. Clinical signs of heart disease - coughing, exercise intolerance, weight loss, rapid/irregular breathing, abdominal swelling, lack of energy, loss of appetite
3. Blood work – determines if the kidneys are healthy enough to metabolize heart medications
4. At home measurements of Resting Respiratory Rate (RRR)
5. Ultrasound/echo - looks at the inner workings of the heart muscle and valves
6. EKG – used to evaluate heart arrhythmias

How to calculate a Resting Respiratory Rate (RRR)

Recent research indicates that a simple, accurate way to monitor heart disease is by monitoring a Resting Respiratory Rate. The normal breathing rate (at rest) for dogs is less than 35 breaths/minute.

First establish a “baseline” by measuring your dog’s resting breathing rate once daily for one week. Pick a time when everything is quiet in the house and your pet is sleeping. Each time the chest rises counts as one breath. Count this for 15 seconds, then multiply this number by 4 to calculate the rate. Average the RRR over the week to obtain your baseline number.

Monitor the RRR once weekly thereafter. Call us if the RRR is over 35, or if a dramatic increase from baseline occurs (for example, if the RRR is usually 15 and it suddenly goes up to 25, this is also a significant change).

What can be done about heart disease?

1. Medications
   1. Lasix- “water pill” – used to help the patient urinate off any excess fluid buildup apparent in the lungs in the chest X-rays
   2. Enalapril- increases heart output and decreases resistance and pressures in the lungs and blood vessels
   3. Vetmedin/pimobendan- helps the heart contract and dilates blood vessels, often used in combination with other drugs in more serious heart disease
2. Diet modifications
   1. Feed a quality dog food that with a lower salt content
   2. be careful about what human food is used as treats or to “hide” the medications in – avoid things high in salt (such as cheese and peanut butter)
3. Exercise/environment modifications/considerations
   1. gentle exercise only – walks, not runs
   2. less tolerant of weather extremes, such as higher humidity and low temperatures

Please call with any questions or concerns - Quarry Hill Park Animal Hospital