Which congenital heart defect is typically indicated by a right-sided heart murmur in a five-month-old cat?

A right-sided heart murmur in a five-month-old cat is most commonly associated with a ventricular septal defect (VSD). This congenital heart defect involves an opening in the ventricular septum, which separates the left and right ventricles. This opening allows for abnormal blood flow between the two ventricles, typically leading to increased blood flow to the right ventricle and consequently the pulmonary circulation. The increased volume can create turbulence that is heard as a murmur, often localized to the right side of the heart.

Ventricular septal defects can lead to a variety of clinical signs, including heart murmurs, exercise intolerance, and signs of congestive heart failure in more severe cases. The specific timing of presentation, such as in a young kitten, fits well because many congenital heart defects tend to become more noticeable as the animal grows and greater cardiac output is required.

In contrast, conditions such as patent ductus arteriosus (PDA) are more typically characterized by a continuous murmur and can manifest on the left side of the heart. An atrial septal defect often results in increased blood flow to the right atrium and is generally less commonly associated with a right-sided murmur in cats. Mitral valve dysplasia usually does not