Which of the following is the most common first symptom of restrictive cardiomyopathy?

Exertional intolerance is recognized as the most common first symptom of restrictive cardiomyopathy due to the condition's impact on the heart's ability to fill properly. In restrictive cardiomyopathy, the heart muscle becomes rigid and less able to expand. This rigidity decreases the heart’s capacity to accommodate incoming blood during diastole, leading to reduced cardiac output during periods of increased physical activity. As a result, patients often experience fatigue and a decreased tolerance for exertion.

Other symptoms such as palpitations, chest pain, and dizziness may occur but typically arise later in the disease process or are more variable in onset and frequency. Identifying exertional intolerance helps in the early recognition of restrictive cardiomyopathy, prompting further investigation and management of this potentially serious condition.