Linked Life Data

9121995

Source:http://linkedlifedata.com/resource/pubmed/id/9121995

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1 Pt 2
pubmed:dateCreated
1997-4-23
pubmed:abstractText
We postulated that reducing peak leading edge shock voltage and its rate of rise (waveform rounding) would reduce energy requirements for cardioversion of AF and AFl, and may therefore reduce patient discomfort. Transvenous defibrillating catheters (In-Control Inc.) were placed in the RAA (active fixation) and the CS of six anesthetized sheep. AF or AFl was induced by electrical stimulation (100 Hz, 2 V; Grass stimulator). A standard trapezoidal biphasic (S) waveform (3-ms duration each phase) was compared with a similar waveform that had the first phase rounded (R). Cardioversion was attempted after 30 seconds of arrhythmia, using a Ventritex HVS-O2 defibrillator modified to allow waveform rounding. Each waveform was randomly tested several times at 100-, 150-, and 200-V leading edges, and percentage cardioversion success calculated. Shock energy was calculated from delivered current and voltage using Flukeview (Fluke, Inc.) software. At 100-V leading edge R (64% success) and S (59%), shocks were similarly efficacious (P = 0.37). However, R delivered less current, voltage, and energy than the comparable S shock (means 1.30 A, 65.0 V, 0.33 J R vs 1.92 A, 94.2 V, 0.47 J S; P = 0.0001). Both waveforms were equally successful at 150 V (88% vs 100%; P = NS) and 200 V (100% vs 100%), but again R delivered less current, voltage, and energy (2.05 A, 102.5 V, 0.82 J R vs 2.78 A, 142.3 V, 1.11 J S at 150 V; 2.76 A, 141.2 V, 1.58 J R vs 3.77 A, 189.4 V, 2.03 J S at 200 V; both P = 0.0001). No arrhythmic or other complications occurred in the 174 shocks delivered. Waveform rounding reduces delivered peak voltage, current, and energy without reducing defibrillation efficacy. To determine if these changes are associated with a reduction in discomfort, patients with AF are currently being cardioverted with these waveforms during electrophysiological studies.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0147-8389
pubmed:author
pubmed:issnType
Print
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
226-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Rounded biphasic waveform reduces energy requirements for transvenous catheter cardioversion of atrial fibrillation and flutter.
pubmed:affiliation
Regional Medical Cardiology Centre, Royal Victoria Hospital, Belfast, N. Ireland.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't