title: Intra-atrial pressure increases rate and organization of waves emanating from the superior pulmonary veins during atrial fibrillation.
abstract: BACKGROUND
  Atrial fibrillation (AF) commonly associates with atrial dilatation by poorly understood mechanisms. We hypothesized that elevation of intra-atrial pressure elicits high-frequency and spatio-temporally organized left atrial (LA) sources emanating from the superior pulmonary veins.
  
  
  RESULTS
  We used a stretch-related AF model in the sheep heart to induce stable episodes of AF (>40 minutes) in 9 animals. Video movies of the LA free wall (LAFW) and LA superior pulmonary vein junction (JPV) were obtained by using di-4-ANEPPS. Electrograms from the right atrium were recorded. At intra-atrial pressures >10 cm H2O, the maximum dominant frequency (DFMax) was significantly higher in the JPV than in the LAFW (12.0+/-0.2 and 10.5+/-0.2 Hz, respectively [mean+/-SEM]; P<0.001). Below 10 cm H2O, DFMax was similar in the JPV and LAFW (10.8+/-0.3 versus 10.2+/-0.3 Hz; P=0.6); DFMax in both JPV and LAFW was significantly higher than in the right atrium (7.8+/-0.3 Hz; P<0.001). Analysis of excitation direction in JPV showed positive correlation between intra-atrial pressure and the number of waves emanating from the left superior pulmonary vein (r=0.79, P=0.02) but not from the LAFW (r=0.54, P=0.09). The number of spatio-temporally periodic waves in the JPV correlated with pressure (r=0.92, P=0.002). In 3 cases, JPV rotors were identified with a cycle length equal to 1/DFMax.
  
  
  CONCLUSIONS
  We demonstrate for the first time that an increase in intra-atrial pressure increases the rate and organization of waves emanating from the superior pulmonary veins underlying stretch-related AF.
authors.affiliation: Institute for Cardiovascular Research, Department of Pharmacology, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY 13210, USA.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Kalifa
authors.forename: José
authors.initials: J
authors.lastname: Jalife
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Zaitsev
authors.forename: Suveer
authors.initials: S
authors.lastname: Bagwe
authors.forename: Mark
authors.initials: M
authors.lastname: Warren
authors.forename: Javier
authors.initials: J
authors.lastname: Moreno
authors.forename: Omer
authors.initials: O
authors.lastname: Berenfeld
authors.forename: Stanley
authors.initials: S
authors.lastname: Nattel
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D001794:Blood Pressure; D018780:Body Surface Potential Mapping; D004396:Coloring Agents; D003971:Diastole; D004106:Dilatation / Q000009:adverse effects; D022062:Electrophysiologic Techniques, Cardiac; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D066298:In Vitro Techniques; D010507:Periodicity; D011667:Pulmonary Veins / Q000503:physiopathology*; D012756:Sheep
chemical_list: D004396:Coloring Agents