title: Control of electrical alternans in canine cardiac purkinje fibers.
abstract: Alternation in the duration of consecutive cardiac action potentials (electrical alternans) may precipitate conduction block and the onset of arrhythmias. Consequently, suppression of alternans using properly timed premature stimuli may be antiarrhythmic. To determine the extent to which alternans control can be achieved in cardiac tissue, isolated canine Purkinje fibers were paced from one end using a feedback control method. Spatially uniform control of alternans was possible when alternans amplitude was small. However, control became attenuated spatially as alternans amplitude increased. The amplitude variation along the cable was well described by a theoretically expected standing wave profile that corresponds to the first quantized mode of the one-dimensional Helmholtz equation. These results confirm the wavelike nature of alternans and may have important implications for their control using electrical stimuli.
authors.affiliation: Division of Cardiology, Weill Medical College of Cornell University, New York, New York 10021, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Christini
authors.forename: Mark L
authors.initials: ML
authors.lastname: Riccio
authors.forename: Calin A
authors.initials: CA
authors.lastname: Culianu
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Fox
authors.forename: Alain
authors.initials: A
authors.lastname: Karma
authors.forename: Robert F
authors.initials: RF
authors.lastname: Gilmour
mesh_terms: D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000473:pathology*; D001703:Biophysics / Q000379:methods*; D004285:Dogs; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation* / Q000379:methods*; D006329:Heart Conduction System; D006352:Heart Ventricles; D011690:Purkinje Fibers / Q000378:metabolism*; D013997:Time Factors; D014693:Ventricular Fibrillation