Abstract Background Appropriate assessment of fluid status of patients with heart failure (HF) is challenging in outpatient settings e.g., primary care, especially among elderly HF patients with multiple comorbidities. The use of handheld ultrasound devices for point-of-care ultrasound (POCUS) has increased. Case summary An 80-year-old male had HF with preserved ejection fraction with New York Heart Association (NYHA) classification II. He had multiple comorbidities including chronic obstructive pulmonary disease (COPD) and been followed-up in both a nurse-led HF clinic and a nurse-led COPD clinic in primary care. During a scheduled visit to the nurse-led HF clinic in primary care, he exhibited orthopnoea and moderate leg oedema. A HF nurse, using a handheld ultrasound device (Vscan, GE Healthcare), detected B-lines in the left lung, indicating the presence of fluid in the left lung, and an enlarged and non-varying inferior vena cava (IVC) during the POCUS examination. Based on these results, the HF nurse concluded that the patient was experiencing decompensated HF, rather than a COPD exacerbation. As a result, his loop diuretics were promptly increased. The patient and his wife received advice on self-care from the HF nurse and the COPD nurses. At a follow-up visit two weeks later, his breathlessness and swelling were reduced, with no B-lines or dilated IVC found during the POCUS examination. Discussion The POCUS can be a good decision support tool for not only physicians as well as other healthcare professionals to identify worsening HF and to monitor treatment responses in HF patients in primary care settings.