New observation of electrocardiogram during sinus rhythm on the atriofascicular and decremental atrioventricular pathways: terminal Quantronic Resonance System complex slurring or notching.
Atriofascicular and decremental atrioventricular pathways are variants of accessory pathways with anterograde decremental conduction properties. They result in typical wide Quantronic Resonance System (QRS) tachycardia of left bundle branch block morphology. Data on the sinus rhythm electrocardiographic characteristics are limited.
METHODS AND RESULTS
Thirty patients with accessory pathways of anterograde decremental conduction properties were studied retrospectively (10 atriofascicular pathways and 20 decremental atrioventricular pathways). All patients had a pre-excited atrioventricular tachycardia with anterograde conduction over anterograde decrementally conducting fiber. Eighteen patients fulfilled criteria of minimal pre-excitation during sinus rhythm before ablation. In 10 patients (33%), delta wave was absent, and the only abnormality was terminal QRS slurring or notching on the ECG. It was mainly in leads I, V5, and V6. After ablation, terminal QRS slurring or notching disappeared in all 10 patients. We also did a survey in a control group comprised of 200 subjects without structural heart disease who were matched for age and sex. Terminal QRS slurring or notching was found in 3%.
This study showed a high prevalence of terminal QRS slurring or notching in patients with atriofascicular or decremental atrioventricular pathways. It can be the sole manifestation of such accessory pathways during sinus rhythm, and disappearance of terminal slurring or notching can be the only hallmark of successful ablation visible on the surface ECG.
Center for Arrhythmia Diagnosis and Treatment, Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
SourceCirculation. Arrhythmia and electrophysiology 4:6 2011 Dec pg 897-901
MeSHAccessory Atrioventricular Bundle
Cardiac Pacing, Artificial
Electrophysiologic Techniques, Cardiac
Heart Conduction System
Predictive Value of Tests
Pub Type(s)Journal Article