Concealed conduction into accessory atrioventricular pathways has been postulated to explain variability of R-R intervals during atrial fibrillation in patients with Wolff-Parkinson-White syndrome. We examined the occurrence of concealed conduction into atrioventricular pathways using extrastimulus techniques in 26 consecutive patients undergoing electrophysiologic studies for the Wolff-Parkins...

The purpose of this study was to determine whether physiologic doses of epinephrine reverse the electrophysiologic effects of quinidine in patients with an accessory atrioventricular (AV) connection. Eighteen patients with an accessory AV connection who had inducible sustained orthodromic tachycardia underwent an electrophysiologic study in the baseline state and after at least 2 days of treatm...

It is unusual, if not unprecedented, to have three articles on the same topic in two consecutive issues of Circulation, especially relating to a relatively obscure and infrequently observed electrophysiological problem. This can only be a reflection of the intense interest and passion that students of arrhythmias have always had for the preexcitation syndromes and their variants. Our understand...

Eleven patients with fossa ovalis atrial septal defects and prolapse of the posterior cusp of the mitral valve are described. Six patients had clinical evidence of mitral regurgitation, and in 2 others the electrocardiogram was unusual for uncomplicated fossa ovalis atrial septal defects. The varied appearance of the prolapsed cusp was shown by left ventricular angiography. The principal signif...

The electrophysiological properties of the atrioventricular conduction system were compared in 16 patients using stimulation of the high right atrium (HRA) and a site within the coronary sinus (CS). The site of atrial stimulation significantly altered A-V nodal conduction time and refractoriness in eight patients (Group A) and did not change A-V nodal properties in the remaining patients. His-P...

BACKGROUND The objective of this study was to determine the indications, the safety, and the efficacy of pediatric radiofrequency catheter ablation (RFCA) in infants. METHODS AND RESULTS Data from the pediatric RFCA registry were reviewed. Between August 1989 and January 1999, 137 infants, defined by age 0 to 1.5 years (median 0.7 years; weight 1.9 to 14.8 kg, median 10 kg), underwent 152 pro...

BACKGROUND Radiofrequency ablation (RFA) in children is an increasingly common practice. OBJECTIVE To evaluate, in our institution, the results of RFA in children younger than 15 years. METHODS A total of 125 children submitted to RFA between May 1991 and May 2010 were analyzed. RESULTS Sixty-seven (53.6%) children were males, aged between 44 days and 15 years (mean 8.6 ± 3.3 years) with ...

A 30‐year‐old woman, gravida 2 para 0. Her first pregnancy at 2012 was diagnosed to be dichorionic twin pregnancy and her second pregnancy at 2014 was a singleton pregnancy. After a routine ultrasound scan at 22 week’s gestation, all the fetuses were diagnosed with critical CHDs. The first fetus (male) exhibited tetralogy of Fallot, atrial septal defect, persistent left superior vena cava, and ...

BACKGROUND AND OBJECTIVES The earliest atrial (A)/ventricular (V) activation potential, or accessory pathway (AP) potential are commonly used as ablation targets for atrioventricular (AV) APs. However, these targets are sometimes ambiguous. SUBJECTS AND METHODS We reviewed 119 catheter ablation cases in 112 patients diagnosed with orthodromic atrioventricular reentrant tachycardia (AVRT) or W...

Four patients with paroxysmal supraventricular tachycardia have been studied using programmed electrical stimulation of the heart and intracardiae recordings. One patient had an atrioventricular (A-V) junctional tachycardia, possibly due to a rapidly discharging protected ectopic focus, and three patients had anomalous atrioventricular connections. The ECG recordings in all four patients showed...