ELECTROPHYSIOLOGICAL PECULIAR FEATURES OF SUPRAVENTRICULAR TACHYCARDIAS IN CHILDEN WITH SHORT PQ INTERVAL

To study electrophysiological peculiar features of the heart conduction system parameters in pediatric patients with supraventricular tachycardias (SVT) with different PQ interval duration, 172 children were examined. Group I consisted of 55 children with short PQ interval, Group II, of 117 children with the normal PQ interval. Transesophageal electrophysiological study was performed in all patients. In the short PQ interval group, patients with paroxysmal atrio-ventricular nodal reciprocal tachycardia (PAVNRT) constituted Group 1 and patients with paroxysmal orthodromic atrio-ventricular reciprocal tachycardia (PAVRT), Group 2. In control group with the normal PQ interval, patients with PAVNRT constituted Group 3 and patients with PAVRT, Group 4. In the children with the short PQ interval, the Wenckebach point was significantly higher than in those with the normal PQ interval (200±30 bpm and 180.5±30.6 bpm, respectively; p=0.01). In the children with the short PQ interval, presence of fast atrio-ventricular conduction (Wenckebach point >200 bpm) was significantly more widespread (54.2% and 31.2%, respectively; p<0.05). In the children with PAVRT, its rate did not significantly differ in both groups (RR: 294.5±37.9 ms and 309.3±39.3 ms, respectively, p>0.05). In the pediatric patients with the short PQ interval, a statistically significantly shorter PAVNRT cycle duration was revealed as opposed to the patients with the normal PQ interval (279.2±57.9 ms and 322.9±54.3 ms; p=0.002). Thus, presence of the short PQ interval has no effect on the PAVRT cycle length but contributes to a shorter PAVNRT cycle length. In the pediatric patients with SVT, occurrence of atrial fibrillation and heart rate during atrial fibrillation did not significantly differ in the case of short and normal QT intervals.

supraventricular tachycardia, PQ interval, CLC syndrome, LGL syndrome, transesophageal electrophysiological study, Wenckebach point

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