Indian Pacing Electrophysiol. J.
Indian Pacing Electrophysiol. J. 2003;
Intra-atrial Re-entrant Tachycardia
with Wenckebach Periodicity
Berardo Sarubbi, MD, PhD, Pasquale Vergara, MD, Michele D’Alto, MD, PhD, Francesco Sessa, MD, Raffaele Calabrò, MD.
Second University of Naples, Chair of Cardiology, GUCH Unit, Division of Paediatric Cardiology, Monaldi Hospital.
Address for correspondence: Dr. Berardo Sarubbi, Via Egiziaca a Pizzofalcone 11, 80132 Napoli, Italy.
A 15-year-old girl, previously asymptomatic for palpitations, underwent a successful atrial septal defect (ASD) device closure. Twelve weeks after the procedure, the patient was admitted complaining of dyspnoea on effort and palpitations. The twelve-lead ECG showed a narrow QRS tachycardia with slight heart rate irregularity, with a mean HR of 170bpm. P waves were not clearly identified with a suspicious of negative P-waves in II, III and aVF leads. No clear relationship could be observed between the suspected P waves and QRS complexes (Figure 1).
Echocardiographic evaluation showed normal position of ASD Device, with no residual shunts, mild dilatation of right atrium and right ventricle with a moderate biventricular systolic function impairment. Transesophageal electrophysiological study showed an atrial tachycardia with a regular A-A interval of 220ms and an A-V conduction delay with a A-V nodal Wenckebach periodicity, leading to an irregular V-V interval ranging between 375 and 300ms (Figure 2). Overdrive atrial pacing at a cycle length of 140ms (almost 70% of the measured A-A cycle) could stop the tachycardia (Figure 3).
The case represents a rare form of intra-atrial re-entry tachycardia with an A-V nodal Wenckebach periodicity. It has been already shown that in intra-atrial re-entry tachycardia, variables degrees of block may be present throughout the entire episode of sustained tachycardia. Neither the ventricles nor the A-V node are required for this arrhythmia. It is the appearance of AV block with maintenance of the supraventricular tachycardia that strongly suggests a supranodal origin. The presence of persistent termination of the arrhythmia through atrial pacing excluded an automatic origin.