Like a calm river or stream, blood flowing normally through the heart is smooth and undisturbed. As the river or stream narrows the flow becomes more rapid and the turbulent rapids emit sounds much louder than the calmer sections. In the heart this turbulence is known as a murmur. Once a murmur has been detected regular visits to the vet are important.
Murmurs are graded 1 to 6 (see grading chart below). The grade, or “loudness”, of the murmur is only sometimes related to the severity of the heart abnormality causing it.
Grading is subjective as it is based on the listeners’ interpretation of the sound. If your Cavalier is excited or anxious the rapid breathing sounds can mask or mimic a murmur. Usually a trained cardiologist can identify a Grade 1 murmur whereas a grade 5 or 6 is more easily identifiable as the murmur is so strong that it can be heard through the chest wall (like water being sprayed against a sheet of cloth).
As the disease progresses the symptoms, initially mild and difficult to detect, can become more severe.
Bands of fibrous tissue, known as the heart chords or strings (the chordae), form part of the heart structure. The chords increase and decrease in tension causing the valves to open and close. When the chords rupture, it causes sudden shortness of breath. When this occurs it is essential a vet or Cardiologist sees your Cavalier.
He may be given oxygen while the heart remodels itself and your Cavalier will become more comfortable.
The symptoms most commonly seen in Cavalier with congestive heart failure include:
- Lack of energy and intolerance of exercise
- Loss of appetite and / or weight loss
- Laboured breathing
- Fainting and swelling of the abdomen (tend to be seen in more severely affected cases)
- Coughing (fluid accumulating on the lungs)
In later stages of heart disease you need to monitor respiratory rate.