Document Detail

Effects of monophasic and biphasic shocks on action potentials during ventricular fibrillation in dogs.
MedLine Citation:
PMID:  8330375     Owner:  NLM     Status:  MEDLINE    
This study determined the response of action potentials during ventricular fibrillation (VF) to timed monophasic and biphasic shocks. A floating glass microelectrode was used to record intracellularly from the anterior right ventricle in 10 open-chest dogs. After 10 seconds of electrically induced VF, 5-millisecond monophasic and 2.5/2.5-millisecond biphasic shocks or 16-millisecond monophasic and 8/8-millisecond biphasic shocks were given via mesh electrodes on either side of the microelectrode. Monophasic and biphasic truncated exponential shocks of 5 V/cm were given with coupling intervals timed from the beginning of a VF action potential to the shock ranging from 50 to 70 milliseconds in 5-millisecond increments. Each coupling interval for each waveform was tested during a different VF episode. The interval between successive activations during VF was 86 +/- 15 milliseconds (mean +/- SD). The refractory period during VF was 61 +/- 5 milliseconds for 5-millisecond monophasic shocks and 66 +/- 6 milliseconds for 2.5/2.5-millisecond biphasic shocks (P < .05). At each coupling interval, action potential duration at 50% repolarization (APD50) was significantly prolonged by the shocks compared with the mean preshock APD50 (P < .05). ADP50 duration increased significantly with increases in the coupling interval (P < .05) for both monophasic and biphasic waveforms. For all coupling intervals together, APD50 prolongation as a percent of the mean preshock APD50 was 170 +/- 55%, 192 +/- 45%, 151 +/- 44%, and 175 +/- 45% for 5- and 16-millisecond monophasic and 2.5/2.5- and 8/8-millisecond biphasic waveforms, respectively. This APD50 prolongation was greater for monophasic than biphasic shocks and was greater for longer than shorter waveforms (P < .05). Thus, during VF, (1) the refractory period for 5-V/cm truncated exponential waveforms lasting 5 milliseconds is approximately 75% of the VF activation interval; (2) the refractory period is shorter for monophasic than for comparable biphasic waveforms; (3) both monophasic and biphasic 5-V/cm shock fields cause prolongation of action potential duration; (4) prolongation of action potential duration increases as the coupling interval increases; and (5) prolongation of action potential duration is greater for monophasic shocks and for longer shock waveforms.
X Zhou; P D Wolf; D L Rollins; Y Afework; W M Smith; R E Ideker
Related Documents :
2705565 - Monophasic action potential recordings in response to graded hyperkalemia in dogs.
2582065 - Activation and inhibition of hageman factor-dependent pathways and the complement syste...
23538395 - Aggravation of pulmonary diffusing capacity in highly trained athletes by 6 weeks of lo...
24421735 - Adaptation of endurance training with a reduced breathing frequency.
16328285 - Short-interval cortical inhibition and corticomotor excitability with fatiguing hand ex...
12495245 - Evidence for the importance of openness to experience on performance of a fluid intelli...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  73     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1993 Aug 
Date Detail:
Created Date:  1993-08-16     Completed Date:  1993-08-16     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  325-34     Citation Subset:  IM    
Department of Medicine, Duke University Medical Center, Durham, N.C.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Action Potentials
Electric Countershock / methods*
Myocardium / pathology
Reaction Time
Refractory Period, Electrophysiological
Ventricular Fibrillation / pathology,  physiopathology*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Force, membrane potential, and [Ca2+]i during activation of rat mesenteric small arteries with norep...
Next Document:  Transferable lipids in oxidized low-density lipoprotein stimulate plasminogen activator inhibitor-1 ...