A patient with restrictive cardiomyopathy presents with dyspnea and peripheral edema. Which initial intervention should the nurse prioritize?

Restrictive cardiomyopathy is characterized by ventricular stiffness, impaired diastolic filling, and elevated filling pressures, leading to pulmonary congestion, systemic venous congestion, and reduced stroke volume, commonly presenting with dyspnea and peripheral edema due to fluid back-up. Rationale: A. Calcium channel blockers may reduce myocardial contractility and worsen already impaired ventricular filling in restrictive cardiomyopathy. They do not address fluid overload and can further decrease cardiac output. Therefore, they are not appropriate as an initial intervention for congestion. B. Increasing physical activity elevates myocardial oxygen demand and venous return, which can worsen dyspnea and congestion. Patients with restrictive physiology have limited ventricular compliance and cannot accommodate increased preload. This may exacerbate symptoms rather than improve them. C. Diuretic therapy reduces intravascular volume and decreases elevated filling pressures associated with restrictive cardiomyopathy. It directly alleviates pulmonary and systemic congestion, improving dyspnea and peripheral edema. This is the most appropriate initial intervention to manage fluid overload. D. A high-sodium diet increases fluid retention and worsens edema and venous congestion. It raises preload and exacerbates symptoms of heart failure physiology. Sodium restriction is typically recommended instead of increased intake in restrictive cardiomyopathy.