Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia globally, linked to significant cardiovascular morbidity and mortality. Catheter ablation has emerged as a primary therapeutic approach, yet substantial recurrence rates limit its long-term efficacy. This review critically examines the molecular mechanisms underlying AF recurrence post-ablation, synthesizing recent findings from current literature. Key molecular pathways identified include structural remodeling mediated by fibrosis involving transforming growth factor-beta 1 (TGF-β1) and matrix metalloproteinases (MMPs), ion-channel dysregulation, inflammatory pathways, autonomic nervous system imbalance, and genetic and epigenetic alterations. Despite considerable advances, critical gaps persist due to small, heterogeneous studies and insufficient long-term follow-up. Comprehensive mechanistic research integrating genomics, proteomics, and advanced imaging is urgently needed to better characterize these pathways. Future studies must validate biomarkers such as TGF-β1, MMPs, connexins, and novel markers like GDF-15 and relaxin. Clinical translation of these molecular insights through precision diagnostics and personalized interventions holds great promise to enhance patient selection, optimize ablation strategies, reduce recurrence, and ultimately improve clinical outcomes in AF management.

Infection from Coxiella burnetti causes Q fever that manifests with vague symptoms. We report a case of an individual admitted to the hospital with recurrent fevers with a history of multiple tick bites. Further workup revealed examination and laboratory findings consistent with Q fever endocarditis. Fevers resolved with doxycycline and hydroxychloroquine. Our case highlights that suspicion for Q fever should be maintained in patients presenting to the hospital with fevers of unknown origin for prompt recognition and appropriate treatment.

Granulomatosis with polyangiitis is a rare systemic disease that causes necrotizing granulomatous inflammation of small- and medium-sized blood vessels. We present the case of a 46-year-old male with medical history significant for chronic sinusitis, prior history of drug abuse, and a recent tooth infection. He was suspected to have infective endocarditis, but further workup revealed diagnostic findings of granulomatosis with polyangiitis. We discuss how the signs and symptoms of granulomatosis with polyangiitis can overlap with infective endocarditis, a pathophysiologically distinct condition with a strikingly similar presentation.

Syphilis can affect multiple organs in the secondary or tertiary stages of the disease. Recent reports have suggested an increase in the incidence of the disease. Involvement of the lung has been rarely described in syphilis. In this report, we discuss the case of a 26-year-old female with past medical history significant for HIV who presented to the hospital with complaints of shortness of breath and underwent thoracentesis; she was found to have syphilis with pulmonary involvement.

Infection from the dengue virus can manifest with a variety of clinical presentations. Cardiac involvement from dengue fever is a rarely reported phenomenon with significant morbidity and mortality. We illustrate the case of a 47-year-old male admitted to the hospital with fevers. The hospital course was complicated with cardiac arrest. Clinicians need to be weary of this rare occurrence particularly in areas with a known prevalence of dengue for prompt recognition and improved patient outcomes.

Cardiac strangulation from leads of an epicardial pacemaker is a rarely reported life-threatening complication. We report the case of a 72-year-old female with history of supraventricular tachycardia status post sino-atrial node ablation with epicardial pacemaker placement who presented to the outpatient setting with shortness of breath. Heart catheterization was performed which showed elevated right and left heart pressures. Compression involving the mid left anterior descending artery and left circumflex artery was noted from an epicardial lead on coronary angiography consistent with cardiac strangulation. The patient was then referred to cardiothoracic surgery for epicardial pacemaker lead removal. The literature has only reported one other survival case of cardiac strangulation in an adult.