Abstract
BACKGROUND/AIM: Atrial fibrillation (AF) and heart failure (HF) commonly co-occur, significantly increasing morbidity and mortality. Poorly controlled AF can contribute to complications like HF and is associated with conditions, such as stroke and pulmonary embolism (PE). This report involves a man with AF who had persistent respiratory symptoms and left-sided chest pain, initially suspected to be PE, but eventually diagnosed as HF. CASE REPORT: A 43-year-old male experienced increasing breathlessness, cough, and fatigue. Initially suspected to have a respiratory infection, his persistent symptoms raised concern for PE. The patient had a history of AF, unsuccessful cardioversion, and long-term non-adherence to beta blockers. Initial assessment revealed persistent respiratory symptoms and elevated levels of C-reactive protein, D-dimer, N-terminal pro-B-type natriuretic peptide, and Troponin T. Chest X-ray showed pulmonary congestion, and echocardiogram confirmed a severely impaired ejection fraction (EF <20%). While the differential diagnosis included community-acquired pneumonia, PE, and HF, the final diagnosis was worsening AF and HF with reduced EF, not PE. CONCLUSION: PE symptoms can overlap with HF, making careful differential diagnosis essential, particularly in AF patients with elevated D-dimer levels, where false positives necessitate caution. This case underscores the importance of thorough differential diagnosis and clinical judgment before ordering tests to avoid misdiagnosis. Long-term non-adherence to beta blockers exacerbated the patient's symptoms, emphasising the critical role of consistent medication use in managing AF and preventing complications like HF. This case report also highlights the importance of thorough investigations, guideline-based treatments and multidisciplinary care in complex AF-HF cases.