Heartworm is a parasite (Dirofilaria immitis) that lives inside the pulmonary arteries and, in cases of severe infestation, the heart itself .
The presence of adult worms inside the pulmonary vessels causes physical obstruction to blood flow and leads to inflammatory changes of the vessel wall that may result in severe lung compromise, heart failure, other organ damage (e.g. renal) and even death.
Luckily this disease does not exist in the UK. However, with an increase in the number of dogs rescued from other European countries, infected dogs may be encountered in the UK.
Medical treatment involves risks and physical removal may be preferable in severely affected patients. This can be performed by introducing catheters and forceps via peripheral vessels into the heart and up to the pulmonary vessels to retrieve the worms.
Our cardiologists have experience with these procedures as they have worked in affected countries previously.
Transoesophageal heart scan showing worms inside the pulmonary artery in a dog rescued from Romania
The retrieval catheter can be seen.
Worms being removed from the same dog.