Response to His‐refractory premature atrial complex with antegrade and retrograde septal depolarization: What is the mechanism?

• Published in: Journal of arrhythmia Vol. 35; no. 5; pp. 776 - 778
• Main Authors: Korkmaz, Ahmet, Ozeke, Ozcan, Cay, Serkan, Ozcan, Firat, Koca, Serhat, Karimli, Emin, Kara, Meryem, Sahin, Mursel, Aras, Dursun, Topaloglu, Serkan
• Format: Journal Article
• Language: English
• Published: Tokyo John Wiley & Sons, Inc 01.10.2019; John Wiley and Sons Inc; Wiley
• Subjects: atriofascicular; Cardiac arrhythmia; Catheters; Electrocardiography; Eps for Resident Physicians; His‐refractory premature atrial complex; LBBB tachycardas; Mahaim; Morphology; Tachycardia; ventricular tachycardia
• ISSN: 1880-4276; 1883-2148
• DOI: 10.1002/joa3.12222

Late PAC during already retrogradely activated septal/AV node region advances ventricular activity indicating antegrade conduction via an active AF rather than a bystander AF or NF accessory pathway. [...]the classical response of antidromic AF Mahaim tachycardia to PAC delivered during septal refractoriness is an advancement of the QRS, without a change in QRS morphology and septal A‐A interval. [...]it is difficult to differentiate the AF pathway from the manifest NFRT/NVRT or even AVRT with bystander AF/NF/NV pathways. Considering that normal intra‐atrial conduction time takes 20‐50 ms, atrial stimulation from the lateral wall affords a wider window of stimulation than stimulating from the septum because of the time interval that the excitation wavefront takes to depolarize the atrial septal region. [...]showing the antegrade or retrograde depolarization/refractoriness of the AV node by septal/proximal CS electrocardiogram is essential, and this maneuver also rules out other forms of AVNRT with bystander preexcitation (such as NV or NFRT) because these tachycardias would also require a PAC to penetrate the septal atrium for termination. Late PAC during already retrogradely activated septal/AV node region advances ventricular activity indicating antegrade conduction via an active AF rather than a bystander AF or NF accessory pathway. [...]the classical response of antidromic AF Mahaim tachycardia to PAC delivered during septal refractoriness is an advancement of the QRS, without a change in QRS morphology and septal A‐A interval.