Miniseries 2-Septal and paraseptal accessory pathways-Part IV: Inferior paraseptal accessory pathways-lessons from surgical and catheter ablation.

Surgeons and electrophysiologists performing accessory pathway ablation procedures have used the term 'posteroseptal' region. This area, however, is neither septal nor posterior, but paraseptal and inferior; paraseptal because it includes the fibro-adipose tissues filling the pyramidal space and not the muscular septum itself and inferior because it is part of the heart adjacent to the diaphragm. It should properly be described, therefore, as being inferior and paraseptal. Pathways in this region can be ablated at three areas, which we term right inferior, mid-inferior, and left inferior paraseptal. The right- and left inferior paraseptal pathways connect the right and left atrial vestibules with the right and left paraseptal segments of the parietal ventricular walls. The mid-inferior paraseptal pathways take a subepicardial course from the myocardial sleeves surrounding the coronary sinus and its tributaries. Our review addresses the evolution of the anatomical concept of the inferior paraseptal region derived from surgical and catheter ablation procedures. We also highlight the limitations of the 12-lead electrocardiogram in identifying, without catheter electrode mapping, which are the pathways that can be ablated without a coronary sinus, or left heart approach.

Diagnostic and therapeutic application of thoracic epidural in a child with intractable cardiac arrhythmias: A case report.

A 3-year-old boy presented with episodes of uneasiness and transient loss of consciousness. Atrial tachyarrhythmias with rapid ventricular rate was diagnosed and initially unsuccessfully treated with oral antiarrhythmic drugs. Subsequent Holter monitoring revealed ventricular arrhythmias. Despite pharmacologic treatment, he needed numerous cardioversions. Surgical sympathectomy was planned. Initially, sympathectomy was achieved using a continuous high thoracic epidural block and was performed to ascertain the efficacy of the thoracic sympathectomy. This successfully reduced the ventricular arrhythmias and the need for antiarrhythmic agents. The epidural infusion was also used for pain relief following the subsequent surgical sympathectomy.