Occurrence of atrioventricular block during supraventricular tachycardia: What is its possible mechanism?
A female patient was admitted to our hospital for catheter ablation arising from paroxysmal supraventricular tachycardia (PSVT). In the laboratory, PSVT (the earliest retrograde atrial activation at the coronary sinus ostium) with intermittent atrioventricular (AV) block could be induced repeatedly. The tachycardia could be terminated during ventricular pacing without retrograde conduction to the atria. Therefore, orthodromic AV reciprocating tachycardia (AVRT) and atrial tachycardia (AT) could be ruled out and AV nodal re-entrant tachycardia (AVNRT) was subsequently considered. Initial attempts using slow or intermediate AV nodal ablation failed to cure the tachycardia. We considered the possibility of orthodromic AV reciprocating tachycardia (AVRT) with AV block occurring during the tachycardia. The tachycardia was successfully terminated during the ablation of the right posteroseptal pathway at the coronary sinus ostium. We hypothesized about the possible explanation that might help to clarify the phenomenon of AV block during SVT in order to provide some guidance to other clinicians confronted with similar patient challenges in the future.
Division of Cardiology, Department of Medicine, Wan-Fang Hospital Taipei Medical University, Taipei, Taiwan, ROC.
Ho-Shun
HS
Cheng
Division of Cardiology, Department of Medicine, Wan-Fang Hospital Taipei Medical University, Taipei, Taiwan, ROC.
Wei-Ta
WT
Chen
Division of Cardiology, Department of Medicine, Wan-Fang Hospital Taipei Medical University, Taipei, Taiwan, ROC.
Jen-Hung
JH
Huang
Division of Cardiology, Department of Medicine, Wan-Fang Hospital Taipei Medical University, Taipei, Taiwan, ROC. Electronic address: td7279@ms25.hinet.net.
Ming-Hsiung
MH
Hsieh
D054537:Atrioventricular Block / Q000209:etiology*; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008875:Middle Aged; D013617:Tachycardia, Supraventricular / Q000150:complications* / Q000503:physiopathology / Q000601:surgery
atrioventricular block; catheter ablation; supraventricular tachycardia