A nurse is caring for an infant who has heart failure and is receiving digoxin. Which of the following findings indicates a positive response to the medication?

A. Capillary refill 4 seconds: A capillary refill time of 4 seconds indicates delayed peripheral perfusion, which suggests inadequate cardiac output. This finding does not reflect improvement in heart failure or a positive response to digoxin therapy. B. Heart rate 187/min: A heart rate of 187/min in an infant indicates tachycardia, which can be a sign of worsening heart failure or digoxin toxicity. A positive response would be reflected by improved cardiac efficiency, not persistent tachycardia. C. Urine output 2 mL/kg/hr: Adequate urine output reflects improved renal perfusion and cardiac output, indicating that digoxin is effectively enhancing myocardial contractility. This is a key indicator of improved heart failure status in infants. D. Respiratory rate 32/min: While this respiratory rate may fall within an acceptable range for some infants, it alone does not specifically indicate improved cardiac output. Respiratory findings must be interpreted in conjunction with perfusion and fluid status indicators.