TY - JOUR
T1 - The effect of an unsuccessful subthreshold shock on the energy requirement for the subsequent defibrillation
AU - Murakawa, Yuji
AU - Gliner, Bradford E.
AU - Shankar, Balakrishnan
AU - Thakor, Nitish V.
N1 - Funding Information:
From the Department. of Biomedical Engineering, The Johns Hopkins School of Medicine. Supported by Grant No. 5K04HL01509 from the National Heart, Lung, and Blood Institute of the National Institutes of Health, and by National Science Foundation Grant No. ENG8451491. Received for publication Sept. 19, 1988, accepted Dec. 8, 1988. Reprint requests: Nitisb V. Thakor, PM, Dept. of Biomedical Engineering, The Johns Hopkins School of Medicine, 720 Rutland Ave., Baltimore, MD 21205.
PY - 1989/5
Y1 - 1989/5
N2 - The effect of an unsuccessful subthreshold shock on the energy requirement for the subsequent defibrillation was studied in 10 anesthetized dogs. Defibrillation was achieved with a spring catheter electrode in the superior vena cava and a patch electrode on the anteroapical ventricular wall. Success rates of defibrillation 20 seconds from the onset of ventricular fibrillation were determined at three energy levels with and without a preceding subthreshold shock. Altogether, 637 episodes of fibrillation-defibrillation were performed (63.7 ± 6.7 per dog). Predicted energy levels for defibrillation success rates of 50% and 80% (E50 and E80) acquired from a logistic regression curve were 0.0303 ± 0.0064 and 0.0367 ± 0.0069 joule/gm, respectively, without subthreshold shocks. E50 and E80 with an unsuccessful subthreshold shock resulted in comparable values (E50: 0.0325 ± 0.0041 joule/gm; E80: 0.0.380 ± 0.0100 joule/gm). Our results suggest that an unsuccessful low-energy shock does not alter the energy requirement for subsequent defibrillation with an implantable defibrillator.
AB - The effect of an unsuccessful subthreshold shock on the energy requirement for the subsequent defibrillation was studied in 10 anesthetized dogs. Defibrillation was achieved with a spring catheter electrode in the superior vena cava and a patch electrode on the anteroapical ventricular wall. Success rates of defibrillation 20 seconds from the onset of ventricular fibrillation were determined at three energy levels with and without a preceding subthreshold shock. Altogether, 637 episodes of fibrillation-defibrillation were performed (63.7 ± 6.7 per dog). Predicted energy levels for defibrillation success rates of 50% and 80% (E50 and E80) acquired from a logistic regression curve were 0.0303 ± 0.0064 and 0.0367 ± 0.0069 joule/gm, respectively, without subthreshold shocks. E50 and E80 with an unsuccessful subthreshold shock resulted in comparable values (E50: 0.0325 ± 0.0041 joule/gm; E80: 0.0.380 ± 0.0100 joule/gm). Our results suggest that an unsuccessful low-energy shock does not alter the energy requirement for subsequent defibrillation with an implantable defibrillator.
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U2 - 10.1016/0002-8703(89)90863-6
DO - 10.1016/0002-8703(89)90863-6
M3 - Article
C2 - 2711966
AN - SCOPUS:0024601245
SN - 0002-8703
VL - 117
SP - 1065
EP - 1069
JO - American heart journal
JF - American heart journal
IS - 5
ER -