Heart murmur
What is a heart murmur?
A heart murmur is an abnormal sound heard when listening to the heart with a stethoscope (called auscultation). It's due to turbulent blood flow in the heart. It means that one (or more) of the four heart valves is leaking, allowing a little bit of blood to flow backwards when the heart contracts.
Greyhounds are often found to have low grade heart murmurs. All dog's heart murmurs are graded 1–6 depending on the severity. Low grade means grade 1-2. A Grade 1 murmur is very soft/quiet and may only be heard intermittently. It is usually only heard in one location on the chest. A Grade 2 murmur is still quiet but is easier to hear and is usually consistently picked up on auscultation.
A heart murmur means that there is a structural abnormality in the heart but is doesn't necessarily mean that the heart isn't working properly.
What are the symptoms of a heart murmur?
Most Greys with low grade heart murmurs live a normal, healthy life without any symptoms.
If symptoms are associated with a murmur, then these are usually related to congestive heart failure (CHF) and include:
- increased breathing rate and effort
- exercise intolerance (getting very tired with minimal exercise)
- coughing
- weight loss
- increased drinking
- fainting/collapse
A very reliable way of picking up pulmonary oedema, the most common problem caused by heart failure, is checking the resting respiratory rate (RRR). This involves counting your dog's breaths during rest or sleep. Normal is less than 30 breaths per minute (1 breath includes 1 in and 1 out). If your dog's RRR is about that, you should seek veterinary help.
How are heart murmurs treated?
In the vast majority of cases, no treatment is required. We recommend monitoring of the heart once a year at vaccination.
If your dog develops signs of exercise intolerance, coughing or collapse we would recommend immediate review.