There are a number of conditions that can lead to an enlarged right ventricle -- although the majority are related to disorders of the pulmonary system or the heart itself. Increased pressures in the pulmonary system can be caused by underlying lung disease (COPD, interstitial lung disease, etc), increased pressures in the pulmonary vasculature (primary/secondary pulmonary hypertension, pulmonary embolism), or problems with the left side of the heart (left heart failure). Problems with the heart can include myocardial infarction, myocarditis, ARVD, or an infiltrative process (amyloidosis, hemachromatosis, etc). After an echocardiogram, right/left heart catheterization and/or cardiac MRI/CT PET might be indicated for further evaluation.
Thank you for replying to my message - it was a great help.
I am due to have a right and left cardiac catherisation.
I'm not a Doctor but it would appear that you have pulmonary issues. The right side of the heart pumps blood through the pulmonary arteries to your lungs, so carbon dioxide can exchange with oxygen in the alveoli in your lungs. If blood flow is restricted, either in the lungs, or the pulmonary arteries, then your right ventricle will have to work much harder. The chamber will grow and weaken over time, trying to overcome the pressure. As the chamber enlarges, the anatomy of the ventricle obviously alters (changes shape) and this can cause problems with the tricuspid valve that sits between the right atrium and ventricle, forcing it out of shape or restricting the muscle control to ensure it closes properly.
Your cardiologist will have to find the cause for the blood flow restriction and aim treatment at this to allow your heart to work less hard. You could have a clot in the pulmonary arteries for example, or some disease in the lungs causing inflammation.