Electrophysiological Abnormalities of the Atrial Muscle in Patients with Manifest Wolff‐Parkinson‐White Syndrome Associated with Paroxysmal Atrial Fibrillation

Abstract

We investigated the electrophysiological properties of the atrial muscle in 33 patients with manifest Wolff-Parkinson-White syndrome. Group I consisted of 13 patients with paroxysmal atrial fibrillation and group II consisted of 20 patients without paroxysmal atrial fibrillation. The anterograde and retrograde effective refractory periods of the accessory pathway and the inducibility of atrioventricular reciprocating tachycardia were not significantly different between the two groups. Endocardial electrograms, obtained by right atrial catheter mapping, were recorded during sinus rhythm from 12 sites of the right atrium in 12 of the 13 group I patients and in all group II patients. An abnormal atrial electrogram was defined as 100 msec or longer in duration, and/or the occurrence of eight or more deflections. Ten (83%) of the 12 group I patients had abnormal atrial electrograms, while only two (10%) of the 20 group II patients had abnormal atrial electrograms, and the difference was significant (P less than 0.01). Thirty-six (26%) of the total 139 electrograms obtained from 12 group I patients and two (1%) of the total 199 electrograms obtained from 20 group II patients fulfilled the criteria for an abnormal atrial electrogram, and the difference was significant (P less than 0.01). The fragmented atrial activity zone, interatrial conduction delay zone, and repetitive atrial firing zone obtained by right atrial extrastimulation were significantly wider in group I than in group II, respectively. It was concluded that electrical abnormalities of the atrial muscle may play an important role in the occurrence of paroxysmal atrial fibrillation in patients with Wolff-Parkinson-White syndrome.

The Different Electrophysiological Characteristics in Children with Wolff‐Parkinson‐White Syndrome Between Those with and Without Atrial Fibrillation

“…This finding was similar to the previous study; there is no relationship between the AF formation and the ERP of AP. 9,10,15,17 Due to the advancement of the RFCA technique in the past decade, many cardiac arrhythmias in children have become curable. However, the management for asymptomatic children with WPW syndrome is still controversial.…”

“…The manifest WPW syndrome children with AF (group 1; n = 11) consisted of seven male and four female children (mean age 15 ± 3 years, range [10][11][12][13][14][15][16][17][18]. The study excluded the patient who had Ebstein's anomaly associated with moderate tricuspid regurgitation and right atrial enlargement.…”

The Influence of Hyperthyroidism in the Electrophysiological Properties of the Atrial Muscle in Paroxysmal Atrial Fibrillation

“…We have previously shown that these indices of atrial vulnerability were greater in patients with hyperthyroidism and PAF than in control subjects [19,20]. The greater atrial IACD and shorter atrial ERP resulted in shortening of the atrial wavelength, which predisposed to development of PAF [19][20][21][22]. The mean atrial ERP in patients with hyperthyroidism (187±7 ms) was significantly shorter than that of controls (215±29 ms, p<0.01).…”

Atrial fibrillation with Wolff-Parkinson-White syndrome

“…The WPW patients with AF have intrinsic atrial muscle abnormalities and most of them present abnormally prolonged and fractionated atrial electrograms that are recorded with atrial endocardial catheter mapping during sinus rhythm . 14 The role of an atrial firing focus as a trigger for AF initiation in the WPW syndrome is not well documented yet. AF can also be initiated by ectopic beats originating from the pulmonary veins, and elsewhere.…”

“…13 Several mechanisms responsible for the development of AF in the WPW syndrome were investigated in detail, namely, the spontaneous degeneration of AVRT into AF, the electrical properties of the AP, the effects of AP on atrial architecture, and the intrinsic atrial muscle vulnerability. [14][15][16][17][18][19][20][21][22] Considering all the mechanisms proposed to explain the development of atrial fibrillation in the WPW syndrome, this review analizes the available data on this singular and interesting topic since AF has a reserved prognostic significance in patients with the WPW syndrome, and has an unusually high incidence in the absence of any clinical evidence of organic heart disease.…”