title: P wave morphology of an arrhythmogenic focus in patients with atrial fibrillation originating from a pulmonary vein or the superior vena cava.
abstract: BACKGROUND
  It was hypothesized that atrial premature contractions (APCs) originating in the pulmonary veins (PVs) or superior vena cava (SVC) can be localized by evaluating characteristics of the P wave.
  
  
  RESULTS
  Thirty-eight patients with paroxysmal atrial fibrillation were studied. P wave polarity and morphology of the ECGs during pacing from PVs were analyzed and compared to those of APCs originating from PVs. The P wave angle and notch in lead II during pacing from the right superior (RS) PV and SVC was compared to those of spontaneous APCs originating from those veins. A positive P wave in lead I was helpful in predicting right PV origin. A positive P wave in lead II distinguished superior PV origin. A notched P wave was helpful in predicting left PV origin. P wave polarity in lead II was positive during RSPV and SVC pacing. P waves in lead II during RSPV pacing had notching in 80%, but all P waves were smooth during SVC pacing. A P wave angle of > 40 degrees and notching in lead II showed RSPV origin.
  
  
  CONCLUSIONS
  These criteria are helpful in selecting which of the 4 PVs should be isolated when APCs cannot be recorded after transseptal puncture.
authors.affiliation: Division of Cardiology, Department of Cardiovascular Disease, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Kimie
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Ichiro
authors.initials: I
authors.lastname: Watanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Okumura
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ashino
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kofune
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kofune
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shindo
authors.forename: Hidezou
authors.initials: H
authors.lastname: Sugimura
authors.forename: Toshiko
authors.initials: T
authors.lastname: Nakai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kunimoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirayama