The heme oxygenase/carbon monoxide system is well-established as a critical regulator of contractile cardiomyocyte development. Although the heme oxygenase/carbon monoxide system is known to have protective effects against arrhythmias by reducing oxidative stress and preserving mitochondrial function in general myocardium, its specific impact on components of the cardiac conduction system, such as the sinoatrial and atrioventricular nodes, is unclear. On the one hand, the antioxidant and anti-inflammatory properties of the heme oxygenase/carbon monoxide system are believed to help maintain normal electrical conduction and prevent arrhythmias. On the other hand, pathological conditions such as age-related sick sinus syndrome have been linked to dysfunction of the heme oxygenase/carbon monoxide system, even though carbon monoxide is detrimental at toxic levels. This review synthesizes the current evidence on the dual nature of the heme oxygenase/carbon monoxide system in the cardiac conduction system. This review highlights the critical need for further investigation of the heme oxygenase/carbon monoxide system's physiological roles and therapeutic potential for conduction pathologies. JOURNAL/mgres/04.03/01612956-990000000-00091/figure1/v/2026-04-13T130436Z/r/image-tiff.

Laparoscopic appendectomy is one of the most frequently performed surgical procedures in pediatric surgery and is considered highly safe. Hemodynamic changes produced by pneumoperitoneum are usually transient and clinically insignificant in otherwise healthy children. We report the case of a nine-year-old boy who developed severe postoperative bradycardia and hypotension following an uncomplicated laparoscopic appendectomy. Electrocardiography and echocardiography demonstrated findings suggestive of sick sinus syndrome with transient ventricular dysfunction requiring inotropic support. The child recovered completely within 72 hours with conservative management. This case highlights an uncommon but important cardiovascular complication following pneumoperitoneum and emphasizes the need for vigilant postoperative monitoring even after routine laparoscopic surgery in children.

Cardiac resynchronisation therapy pacemaker (CRT-P) placement and coronary sinus cannulation (CSC) are notably challenging in dextrocardia (DXC).

Bradycardia has a broad differential, which can be narrowed by history, physical examination, and electrocardiogram. Symptomatic cases often stem from sick sinus syndrome or atrioventricular block. High-risk, cannot-miss causes include hyperkalemia, myocardial ischemia, toxins, hypoxia, increased intracranial pressure, and thyroid dysfunction. Early recognition is critical to prevent progression to bradycardic arrest. Management ranges from targeted interventions and antidotes to pharmacologic and electrical therapies.

Sinonasal and petrous bone fungal infections are rare and life-threatening conditions that essentialy arise in immunocompromised patients. They are mainly due to Aspergillus in patients with hematological diseases and to Mucorales in diabetic. Invasive fungal sinusitis can be acute (invasive aspergillosis, rhino-orbito-cerebral mucormycosis) but chronic invasive sinusitis can also exist (invasive chronic fungal sinusitis and granulomatous invasive fungal sinusitis). Petrous bone fungal infections are similar to bacterial necrotizing otitis externa and are most often due to Aspergillus. The diagnosis must be made as early as possible with surgical biopsies, to allow early therapeutic management. Histopathological analysis is essential to confirm the diagnosis. The treatment is multidisciplinary and combines antifungal treatments with etiological care, sometimes associated with debridement surgery especially for mucormycosis.

Catheter ablation in longstanding persistent atrial fibrillation (AF) presents unique challenges, particularly in patients with large left atria and prior atrioventricular nodal dysfunction. While novel pulsed-field ablation (PFA) has been shown to be safer, no data yet show that a large focal lattice-tip catheter may be more effective. We present a 66-year-old man with symptomatic, longstanding, persistent AF and underlying sick sinus syndrome who underwent catheter ablation using Affera 3D mapping (Medtronic, Minneapolis, MN) and the Sphere 9 catheter (Medtronic, Inc, Mounds View, MN) to provide a combined pulsed field and radiofrequency approach. High-resolution electroanatomic mapping guided pulmonary vein isolation, which was extended to include posterior wall isolation, mitral isthmus ablation, and cavotricuspid isthmus ablation due to multiple arrhythmia foci. During delivery of PFA to complete posterior wall isolation, there was termination of AF to a normal sinus rhythm. This case highlights the utility of comprehensive lesion sets and advanced mapping technologies in achieving rhythm control in complex persistent AF.