Respiratory infections as triggers of acute cardiovascular complications: a case series of new-onset atrial fibrillation and heart failure

Background Respiratory infections, including pneumonia and influenza, are recognised precipitants of cardiovascular events. Systemic inflammation, hypoxemia, and hemodynamic stress may precipitate new-onset atrial fibrillation (AF) or acute decompensated heart failure (HF). Early recognition is essential for timely management and prevention. Methods We conducted a retrospective review of 6 patients admitted under one respiratory physicians from June–Sept, 2025 with primary respiratory infections who subsequently developed new-onset AF or acute HF decompensation. Clinical characteristics, diagnostic investigations, management strategies, and outcomes were extracted from discharge letters. Analysis Case 1: 83/M with community-acquired pneumonia developed new-onset AF with rapid ventricular response, managed with rate control and initiation of anticoagulation. Case 2: 85/F, Active-smoker, with new oxygen requirement and shortness of breath post left knee replacement. Experienced acute HF decompensation, and new onset AF managed with intravenous diuretics and supplemental oxygenation. Early Cardiology consult was taken and suggested cardiac strain secondary to sepsis. Case 3: 60/M, heavy smoker with Left lower-lobe pneumonia developed acute pulmonary oedema and AF, requiring long hospital stay, recurrent deterioration, antibiotic escalations and intensive guideline-directed therapy. Case 4: 88/ M, with Transient Ischemic Stroke but then developed shortness of breath and cough and was treated for RTI followed by new onset AF picked on Echocardiography (delayed diagnosis), treated with anticoagulation and rate control. Case 5: 84/F, Hypertensive admitted with respiratory sepsis, developed in-patient new heart failure and new fast atrial fibrillation and was managed with IV diuresis, anti-coagulation, rate control and antibiotics. Case 6: 91/F, with respiratory sepsis after failed outpatient antibiotics, presented in the ED with AF (HR >180 bpm), requiring electrical cardioversion (100–120 J) and amiodarone infusion. Management included steroids, nebulisers, IV furosemide, and antibiotics. She was readmitted within 60 days with recurrent symptoms, necessitating aggressive diuresis and escalation of rate control therapy. Results In this series, respiratory infections precipitated clinically significant cardiovascular events necessitating escalation of care. All patients received guideline-directed therapy, including anticoagulation and heart failure management. Two of the patient were readmitted, one within 2-months and other within 6-months. Conclusion This case series reveals the interplay between respiratory infections and acute cardiovascular complications. Clinicians should remain vigilant for AF and HF in patients admitted with respiratory infections. Early identification facilitates timely initiation of anticoagulation, rhythm control, and guideline-directed HF therapy, reducing morbidity, rehospitalization, and adverse outcomes.