title: Antegrade and retrograde decremental conduction properties of an accessory pathway associated with the coronary sinus musculature.
abstract: A 32-year-old man underwent catheter ablation of an orthodromic atrioventricular reentrant tachycardia. The sinus rhythm electrocardiogram exhibited a normal PQ interval and no delta waves, but atrial pacing produced a prolonged PQ interval and wide QRS morphology with right bundle-branch block due to antegrade accessory pathway (AP) conduction. During the tachycardia, atrial double potentials consisting of the coronary sinus musculature (CSM) and left atrial (LA) potentials were observed. Ventricular extrastimulation exhibited retrograde decremental conduction with an identical atrial activation sequence as during the tachycardia. A radiofrequency application within the posterolateral CS during ventricular pacing eliminated the CSM-LA conduction and concomitantly the ventriculoatrial conduction via the AP was abolished. In this case, the CSM was associated with the bidirectional decremental conduction properties of the AP, and the antegrade slow conduction resulted in the absence of a shortening of the PQ interval and delta waves during sinus rhythm despite the continuous presence of antegrade AP conduction.
authors: Division of Cardiology, Gunma Prefectural Cardiovascular Center, 3-12 Kameizumi-machi, Maebashi City, Gunma 371-0004, Japan.
authors: Kohki
authors: K
authors: Nakamura
authors: Division of Cardiology, Gunma Prefectural Cardiovascular Center, 3-12 Kameizumi-machi, Maebashi City, Gunma 371-0004, Japan.
authors: Shigeto
authors: S
authors: Naito
authors: Division of Cardiology, Gunma Prefectural Cardiovascular Center, 3-12 Kameizumi-machi, Maebashi City, Gunma 371-0004, Japan.
authors: Kenichi
authors: K
authors: Kaseno
authors: Division of Cardiology, Gunma Prefectural Cardiovascular Center, 3-12 Kameizumi-machi, Maebashi City, Gunma 371-0004, Japan.
authors: Shigeru
authors: S
authors: Oshima
keywords: accessory pathway; atrial double potential; atrioventricular reentrant tachycardia; catheter ablation; coronary sinus musculature; decremental conduction property