Miniseries 1-Part IV: How frequent are fasciculo-ventricular connections in the normal heart?

Aims: Seeking to account for accessory atrioventricular conduction potentially leading to ventricular pre-excitation, Mahaim in the mid-20th century had described pathways between the atrioventricular conduction axis and the muscular ventricular septum. We aimed to look for such 'paraspecific' connections in adult human hearts.

Methods And Results: We serially sectioned 21 hearts, covering the triangle of Koch and the aortic root, and assessing the atrioventricular node, the penetration of the conduction axis, and the bundle branches in our search for fasciculo-ventricular connections.

Esophago-pericardial fistula after catheter ablation of atrial fibrillation: A review.

Introduction: Much have been reported about esophago-left atrium fistula. However, esophago-mediastinal fistula, not reaching the left atrium, has not been studied as a different clinical entity, with different management.

Methods And Results: We review and discuss the literature of esophago-mediastinum fistula after catheter ablation for atrial fibrillation with emphasis on the following points: the timing of its occurrence after ablation; the mechanisms and localization of the fistula; and its natural history.

Unusual variants of pre-excitation: From anatomy to ablation: Part III-Clinical presentation, electrophysiologic characteristics, when and how to ablate nodoventricular, nodofascicular, fasciculoventricular pathways, along with considerations of permanent junctional reciprocating tachycardia.

The recognition of the presence, location, and properties of unusual accessory pathways for atrioventricular conduction is an exciting, but frequently a difficult, challenge for the clinical cardiac arrhythmologist. In this third part of our series of reviews, we discuss the different steps required to come to the correct diagnosis and management decision in patients with nodofascicular, nodoventricular, and fasciculo-ventricular pathways. We also discuss the concealed accessory atrioventricular pathways with the properties of decremental retrograde conduction that are associated with the so-called permanent form of junctional reciprocating tachycardia.

Part II-Clinical presentation, electrophysiologic characteristics, and when and how to ablate atriofascicular pathways and long and short decrementally conducting accessory pathways.

Recognition of the presence, location, and properties of unusual accessory pathways for atrioventricular conduction is an exciting, frequently difficult, challenge for the clinical cardiac arrhythmologist. In this second part of our series of reviews relative to this topic, we discuss the steps required to achieve the correct diagnosis and appropriate management in patients with the so-called "Mahaim" variants of pre-excitation. We indicate that, nowadays, it is recognized that these abnormal rhythms are manifest because of the presence of atriofascicular pathways.

Unusual variants of pre-excitation: From anatomy to ablation: Part I-Understanding the anatomy of the variants of ventricular pre-excitation.

The famous quotation of Winston Churchill, made in his radio broadcast of 1939 regarding Russia's next move, specifically "A riddle wrapped up in a mystery, inside an enigma," perfectly fits the current understanding of unusual accessory atrioventricular pathways, including the variants producing ventricular pre-excitation. It was many decades after their original descriptions that we came better to begin to understand most of their structure-function relationships. Their mysterious pathophysiology was sometimes unveiled after invasive treatments, such as surgical ablation of the atrioventricular conduction axis instead of the accessory pathway itself.

When and how does a single ventricular premature beat initiate and terminate supraventricular tachycardia?

Background: The differential diagnosis of a supraventricular tachycardia (SVT) is accomplished using a number of pacing maneuvers. The incidence and mechanism of a single ventricular premature beat (VPB) on initiation and termination of tachycardia were evaluated during programmed electrical stimulation (PES) of the heart in patients with the two most common regular SVTs: atrioventricular re-entrant tachycardia (AVNRT) and orthodromic atrioventricular tachycardia (AVRT).

Methods: Three hundred and thirty-seven consecutive patients aged above 18 years with an inducible sustained AVNRT or AVRT were prospectively enrolled.

Percutaneous Catheter Ablation of Epicardial Accessory Pathways.

Radiofrequency (RF) catheter ablation is the treatment of choice in patients with accessory pathways (APs) and Wolff-Parkinson-White syndrome. Endocardial catheter ablation has limitations, including the inability to map and ablate intramural or subepicardial APs. Some of these difficulties can be overcome using an epicardial approach performed through the epicardial venous system or by percutaneous catheterisation of the pericardial space.

Accessory atrioventricular pathways refractory to catheter ablation: role of percutaneous epicardial approach.

Background: Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed.

Methods And Results: We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures.

Postablation-acquired short atrioventricular Mahaim-type fibers: observations on their clinical, electrocardiographic, and electrophysiologic profile.

Background: The electrophysiologic characteristics of decrementally conducting accessory pathways (APs) are well described; however, little is known about decrementally conducting APs caused by the radiofrequency ablation of a rapidly conducting AP.

Objective: To report the clinical, electrocardiographic, and electrophysiologic characteristics of 6 patients who developed a decremental AP after an attempt at ablation.

Methods: We compared the clinical and electrophysiologic characteristics of 295 consecutive patients with the Wolff-Parkinson-White syndrome who underwent radiofrequency ablation of 311 manifest APs (group A) with those of 6 patients with the Wolff-Parkinson-White syndrome in whom a decrementally conducting AP was detected after an attempt at ablation.