Which is a primary characteristic of right ventricular hypertrophy?

A primary characteristic of right ventricular hypertrophy is indeed the increased size of the right ventricle. This condition generally arises as a response to increased workload on the right side of the heart, commonly due to conditions such as pulmonary hypertension or chronic respiratory disorders that place stress on the right ventricle. As the ventricle works harder to pump blood into the pulmonary arteries, the muscle fibers adaptively thicken, resulting in hypertrophy, which is the enlargement of the heart muscle.

The other options are related to various aspects of cardiac function or physiology but do not define the primary characteristic of right ventricular hypertrophy. Abnormal valve closure may occur with various cardiac conditions, but it is not a defining characteristic of right ventricular hypertrophy itself. Reduced lung capacity can be associated with conditions leading to right ventricular hypertrophy, such as chronic obstructive pulmonary disease (COPD), but it does not directly characterize the hypertrophy itself. Increased left ventricular output is typically not a feature of right ventricular hypertrophy and instead may refer to conditions affecting the left heart, making it unrelated to the primary defining characteristic of right ventricular hypertrophy.