title: [The Myocardial Sleeves of the Pulmonary Veins: Potential Implications For Atrial Fibrillation].
abstract: Pulmonary veins (PVs) are thought to play an important role in the initiation of atrial fibrillation. However, systematic microelectrode studies from different regions of the left atria and PV myocardium remain limited.
  
  
  RESULTS
  A 2-microelectrode technique was used to characterize electrophysiological properties of rat left atrial and PV myocardium, at baseline and during electrical stimulation. PV myocardium was characterized by prolonged action potential duration (APD) (74+/-2 ms in the PV mouth vs. 59+/-3 ms in the left atriul, p<0.01), high degree of APD alternans, and spontaneous depolarizations of resting membrane potential recorded without electrical stimulation. In the distal part of the PV, we found an unexcitable area which was characterized by a depolarized resting potential (50+/-4 mV vs. 82+/-2 mV in the left atrium, p<0.01) and conduction blocks.
  
  
  CONCLUSIONS
  PV myocardium demonstrates a high degree of action potential duration heterogeneity and conduction discontinuities which may form a functional substrate for reentrant arrhythmias and provoke atrial fibrillation.
authors.affiliation: Institute of Experimental Cardiology of Russian Cardiology Research and Production Complex, Moscow, Russia.
authors.forename: Y V
authors.initials: YV
authors.lastname: Egorov
authors.affiliation: Institute of Experimental Cardiology of Russian Cardiology Research and Production Complex, Moscow, Russia.
authors.forename: L V
authors.initials: LV
authors.lastname: Rozenshtrauh
mesh_terms: D000200:Action Potentials; D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D016275:Atrial Function; D006321:Heart / Q000502:physiology*; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008564:Membrane Potentials; D011667:Pulmonary Veins / Q000502:physiology*; D051381:Rats
keywords: acetylcholine; action potential; norepinephrine; pulmonary vein