Heart failure is a leading cause of emergency department admissions, with dyspnea and psychological distress being among the most common presenting symptoms. This randomized controlled trial aims to evaluate the effect of nurse-guided diaphragmatic breathing and pursed-lip breathing exercises on dyspnea and psychological distress in patients presenting to the emergency department with heart failure. A total of 112 eligible participants will be randomly assigned in a 1:1 ratio to either an intervention group receiving breathing exercises in addition to standard care or a control group receiving standard care alone. Dyspnea severity will be assessed using the Modified Borg Dyspnea Scale, and psychological distress will be assessed using the Distress Thermometer at predefined time points. The findings are expected to provide evidence for the effectiveness of a simple, low-cost, nurse-led non-pharmacological intervention in improving symptom management in patients with heart failure.