A supraventricular tachycardia with the atrial interval variability:
What is the mechanism?
- Atsushi Doi,
- Kazuya Sugioka,
- Takuya Tsukamoto,
- Sawa Tanaka,
- Naoko Takaoka,
- Toshiharu Iwamura,
- Takahiko Kawarabayashi,
- Daiju Fukuda
Abstract
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A 57-year-old woman with frequent palpitations was referred for
radiofrequency ablation. The baseline 12-lead electrocardiogram and
echocardiography were normal. The baseline atrio-His (AH) and
His-ventricular (HV) intervals were 70 and 35 ms, respectively. Dual
atrioventricular (AV) nodal physiology was not observed during
programmed atrial stimulation. Ventriculoatrial conduction showed a
decremental and concentric pattern, with the earliest atrial activation
recorded in the His bundle region. There was no evidence of a jump-up
phenomenon during programmed ventricular stimulation. Supraventricular
tachycardia (SVT) with variable AH and His-atrial (HA) intervals was
induced by extra atrial stimulation without any jump-up in the AH
interval. The earliest atrial activation during SVT was recorded at the
coronary sinus (CS) 7,8 region, corresponding to the CS ostium, which
differed from the atrial activation sequence during ventricular pacing.
The atrial-atrial (AA) intervals demonstrated variability exceeding 50
ms without any alteration in the atrial activation sequence (Figure 1A).
Ventricular entrainment pacing was performed during SVT (Figure 1B).
Transient 2:1 AV conduction was observed during SVT (Figure 1C). Based
on these findings, what is the mechanism of the variability in the AA,
AH, and HA intervals during tachycardia?22 Nov 2024Submitted to Journal of Cardiovascular Electrophysiology 23 Nov 2024Submission Checks Completed
23 Nov 2024Assigned to Editor
23 Nov 2024Review(s) Completed, Editorial Evaluation Pending
24 Nov 2024Reviewer(s) Assigned