lucienne,
There are multiple causes of an enlarged right ventricle. There are also different ways that the ventricle can be enlarged. Either high pressure (ie..pulmonary hypertension) can cause the thickness of the ventricle to increase or increased volume from shunting (ie..Atrial septal defects) can cause the diameter of the chamber to increase. Sometimes, its a combination of both. If your husband is a large man, he just may have a larger right ventricle.
You need to stop worrying about this until you see your doc. Once, they have the opportunity to review your case they can discuss the finding and the cause with you.
good luck