Combining Stimulus Direction And Waveform For Optimization Of Threshold Stimulation Of Isolated Ventricular Myocytes.

dc.creatorBassani, Rosana A
dc.creatorLima, Katherine A
dc.creatorGomes, Paulo A P
dc.creatorOliveira, Pedro X
dc.creatorBassani, José W M
dc.date2006-Sep
dc.date2015-11-27T13:05:37Z
dc.date2015-11-27T13:05:37Z
dc.date.accessioned2018-03-29T01:03:07Z
dc.date.available2018-03-29T01:03:07Z
dc.identifierPhysiological Measurement. v. 27, n. 9, p. 851-63, 2006-Sep.
dc.identifier0967-3334
dc.identifier10.1088/0967-3334/27/9/008
dc.identifierhttp://www.ncbi.nlm.nih.gov/pubmed/16868351
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/196847
dc.identifier16868351
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1297080
dc.descriptionElectric field stimulation is widely used for heart pacing and arrhythmia reversion. In this study, we analysed the influence of waveform and direction of external stimulating electric field on the excitation threshold of isolated ventricular myocytes. The threshold field (E(T)) was lower when the field was applied longitudinally (E(T,L)) rather than transversally (E(T,T)) to the cell major axis. Rheobase was greater for transversal stimulation, but chronaxie and estimated membrane polarization were similar for both directions. The calculated maximal variation in membrane potential at the threshold (DeltaV(T) approximately 15 mV) was insensitive to field direction. As DeltaV(T) values were similar, we assumed that the E(T,T)/E(T,L) ratio might be described solely as the ratio of the major and minor cell semi-axes. Accordingly, the ratio thus estimated was comparable to that determined experimentally. Stimulus waveform significantly affected both E(T) and DeltaV(T), which were greater for monophasic versus biphasic stimuli. Direction and waveform effects were independent. We conclude that (a) direction affects E(T) by its influence on the ability of a given field intensity to cause threshold membrane polarization and (b) threshold-lowering effects of longitudinal stimulation and biphasic waveforms apparently depend on different mechanisms, are additive and thus may be combined to decrease the energy requirement for myocardial stimulation.
dc.description27
dc.description851-63
dc.languageeng
dc.relationPhysiological Measurement
dc.relationPhysiol Meas
dc.rightsfechado
dc.rights
dc.sourcePubMed
dc.subjectAction Potentials
dc.subjectAnimals
dc.subjectAnisotropy
dc.subjectCells, Cultured
dc.subjectComputer Simulation
dc.subjectDifferential Threshold
dc.subjectElectric Stimulation
dc.subjectHeart Ventricles
dc.subjectMale
dc.subjectMembrane Potentials
dc.subjectModels, Cardiovascular
dc.subjectMyocytes, Cardiac
dc.subjectRats
dc.subjectRats, Wistar
dc.subjectVentricular Function
dc.titleCombining Stimulus Direction And Waveform For Optimization Of Threshold Stimulation Of Isolated Ventricular Myocytes.
dc.typeArtículos de revistas


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