Atypical location of Coumel Tachycardia in Adult: Case Report

Coumel Tachycardia or Incessant Junctional Reentrant (IJRT) generally affects the infant-juvenile population and is characterized by tachycardia due to atrioventricular reentry (AV) mediated by an exclusive, slow, decremental retrograde conduction pathway mostly located in the posterosseptal region of the tricuspid ring. Case report: The present study reported the case of an adult, 49 years old, with IJRT of atypical location. The patient reported feeling palpitations for 5 years with worsening in the last 6 months. After one of his seizures, an electrocardiogram (ECG) documented tachycardia due to AV reentry with a long RP ‘interval. Subjected to an electrophysiological study, an accessory pathway of exclusive retrograde conduction with decreasing characteristics was observed, located in the right mid-septal region. There was easy induction of IJRT, remaining sustained throughout the study. A radiofrequency ablation was performed in the mid-septal D region with interruption of tachycardia, with no more atrioventricular retrograde conduction, the procedure ended without complications. Discussion: Interestingly, the case described differs both in terms of the age range of the most frequent involvement of the IJRT (children and young people), as well as the most common location of the accessory pathway (posterior and postero-septal region of the tricuspid ring). Ablation proved to be effective in this case and is the treatment of choice for IJRT despite the anomalous location of the accessory pathway (Middle-septal D: described in bibliographic reviews in only 7% of IJRT cases) and a potentially dangerous region due to proximity to the trunk of the His beam.

Retrograde sharp potential resembling the his-bundle electrogram: is this a case of atrioventricular re-entrant tachycardia involving twin atrioventricular nodes with the anterior node exhibiting only retrograde conduction?

A 2-year-old male with right isomerism was referred for supraventricular tachycardias. Atrial pacing study revealed that anterograde conduction was only through the posterior atrioventricular node. During the mapping of ventriculoatrial conduction, we identified a sharp potential resembling a His-bundle electrogram with a decremental property at the anterior wall of the common atrium. Catheter ablation for the potential eliminated the anterior ventriculoatrial conduction, thereby indicating retrograde activation of the possible anterior atrioventricular node.

NON-INVASIVE ELECTROCARDIOGRAPHIC IMAGING IN DIFFERENTIAL AND TOPICAL DIAGNOSIS OF VENTRICULAR TACHYCARDIA WITH VENTRICULOATRIAL RETROGRADE CONDUCTION

A case report of differential and topical diagnosis of ventricular tachycardia from right ventricular outflow tract endocardial surface with ventriculoatrial retrograde conduction using non-invasive electrocardiographic imaging is presented.Conflicts of Interest: M.Chmelevsky - clinical specialist EP Solutions SA, S.Zubarev and M.Budanova - consultants EP Solutions SA.

Concealed accessory pathways and related tachycardias

Conduction from the atria to the ventricles normally occurs via the atrioventricular node–His–Purkinje system. Accessory pathways (APs) directly connect the atrium and ventricle and bypass the atrioventricular node, bridging the mitral or, less commonly, the tricuspid annulus. Concealed APs conduct electrical impulses retrogradely from the ventricles to the atria, but not antegradely from the atria to the ventricles. Approximately 40% of all APs are concealed, and orthodromic atrioventricular reentrant tachycardia due to concealed APs is present in up to 15% of patients with supraventricular tachycardias referred for catheter ablation. Most concealed APs are left-sided, exhibiting non-decremental retrograde conduction. Tachyarrhythmias due to concealed APs are managed similarly to those supraventricular tachycardias associated with manifest APs, and symptomatic tachyarrhythmias are successfully treated by radiofrequency catheter ablation in the majority of patients.