title: Evolution of action potential alternans in rabbit heart during acute regional ischemia.
abstract: This study investigates the development of the spatiotemporal pattern of action potential alternans during acute regional ischemia. Experiments were carried out in isolated Langendorff-perfused rabbit heart using a combination of optical mapping and microelectrode recordings. The alternans pattern significantly changed over time and had a biphasic character reaching maximum at 6-9 min after occlusion. Phase I (3-11 minutes of ischemia) is characterized by rapid increase in the alternans magnitude and expansion of the alternans territory. Phase I is followed by gradual decline of alternans (Phase II) in both magnitude and territory. During both phases we observed significant beat-to-beat variations of the optical action potential amplitude (OAPA) alternans. Simultaneous microelectrode recordings from subepicardial and subendocardial layers showed that OAPA alternans coincided with intramural 2 : 1 conduction blocks. Our findings are consistent with the modeling studies predicting that during acute regional ischemia alternans can be driven by 2 : 1 conduction blocks in the ischemic region.
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Irma
authors: I
authors: Martišienė
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Jonas
authors: J
authors: Jurevičius
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Rūta
authors: R
authors: Vosyliūtė
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Antanas
authors: A
authors: Navalinskas
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Rimantas
authors: 0000-0002-7590-7606
authors: R
authors: Treinys
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Regina
authors: R
authors: Mačianskienė
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania.
authors: Rimantas
authors: R
authors: Benetis
authors: Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210-2375, USA.
authors: Arvydas
authors: A
authors: Matiukas
authors: Laboratory of Membrane Biophysics, Institute of Cardiology, Lithuanian University of Health Sciences, LT-50009 Kaunas, Lithuania ; Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210-2375, USA.
authors: Arkady M
authors: AM
authors: Pertsov
mesh_terms: D000200:Action Potentials; D000818:Animals; D005936:Glucans; D000067268:Isolated Heart Preparation; D017202:Myocardial Ischemia / Q000503:physiopathology*; D011817:Rabbits; D056969:Voltage-Sensitive Dye Imaging
chemical_list: D005936:Glucans; C439358:alternan