A female neonate with congenital complete heart block developed atrioventricular conduction through an accessory pathway. Despite sinus rhythm and an adequate heart rate she developed severe dilated cardiomyopathy and died at age 14 months. This case illustrates that underlying heart block can be present in individuals with asymptomatic Wolff-Parkinson-White syndrome and that the dilated cardio...

Reciprocating tachycardia in a patient with a leftsided atrioventricular accessory pathway (AP) (Kent bundle, type A) capable only of ventriculo-atrial (V-A) transmission is described. The V-A AP is established as an essential link of the tachycardia circuit, as evidenced by : 1) retrograde atrial activation of the left atrium (LA) 60 msec or more before the low and high right atrium during rec...

fundamental observations about cardiac pathophysiology. The purpose of this editorial comment is to expand the findings covered in that review to demonstrate how clinical investigators have applied those advances in electrocardiography toward an understanding of the physiology of cardiac arrhythmias (2–4). This knowledge has enabled the practicing cardiologist, armed with no more than a pair of...

BACKGROUND Cryoablation is increasingly utilized in children because of its safety profile. Recently, larger catheter tips have been more widely used to improve long-term success rates. The aim of this study was to assess the safety and efficacy of 8-mm-tip catheters for cryoablation of right-sided accessory pathways (APs) in children. METHODS Electrophysiological procedures were performed us...

Records from patients with the Wolff-Parkinson-White syndrome were reviewed with particular emphasis on the occurrence of bundle-branch block aberration during reciprocating tachycardia and the significance of this observation with respect to accessory pathway location. Increase by greater than 25 ms in the ventriculoatrial interval during reciprocating tachycardia with bundle-branch block, whe...

BACKGROUND Cardiac memory is a phenomenon characterized by transient T-wave abnormalities occurring during normal sinus rhythm, after a period of altered ventricular depolarization, where the T-wave vector has the same direction as the vector of the previously altered QRS complex (T-wave inversion). It is a form of electrical remodelling of the ventricular, where the T-wave follows ("remembers"...

A cryosurgical instrument was used to ablate atrioventricular conduction. The procedure was carried out in 20 dogs and subsequently in three patients with drug resistant, life-threatening supraventricular tachycardias. In patients, the cryosurgical unit lowered the temperature of the His bundle area to 0 degrees C, effecting complete but reversible heart block. Rewarming resulted in resumption ...

Intracardiac electrophysiological studies were performed in two patients with Wolff-Parkinson-White (WPW) syndrome. Atrial pacing at increasing rates or shorter coupling intervals produced inscription of the forward His bundle deflection at progressively longer intervals after the onset of ventricular depolarization. There was an associated increase in QRS duration without any change in the P-R...

OBJECTIVES We investigated the safety and efficacy of cryoablation in the treatment of pediatric patients with accessory pathways (APs) located near the atrioventricular junction and with atrioventricular nodal re-entrant tachycardia (AVNRT). BACKGROUND Few studies concern cryoablation in a significant number of pediatric patients involving treatment for supraventricular tachycardias (SVTs) w...

Data are reported on three patients with the permanent form of junctional reciprocating tachycardia, in whom conduction over a slow accessory pathway was observed after His bundle ablation. Tachycardia was almost incessant and showed a retrograde P wave (P') and RP' interval longer than P'R interval in all patients; during sinus rhythm, the PR interval was normal and there was no evidence of a ...