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The Ventricular Defibrillation and Upper Limit of Vulnerability Dose‐Response Curves
Author(s) -
MALKIN ROBERT A.,
SOUZA JOSEPH J.,
IDEKER RAYMOND E.
Publication year - 1997
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1997.tb00851.x
Subject(s) - defibrillation , medicine , defibrillation threshold , ventricular fibrillation , ventricle , cardiology , superior vena cava , fibrillation , atrial fibrillation
DF and ULV Dose‐Response Curves. Introduction: A stimulus delivered in the T wave of a paced cardiac cycle can induce ventricular fibrillation (VF). If the stimulus strength is increased, the probability of inducing VF decreases. This study determines an ideal mathematical model (a dose‐response curve) for the relationship between the shock strength and the probability of inducing VF or defibrillating. Methods and Results : Defibrillating electrodes were implanted in the right ventricle and superior vena cava in 16 pigs. The electrode in the vena cava was electrically connected to a cutaneous patch. The same electrodes were used for both VF induction and defibrillation. T wave stimuli were given at the peak of the T wave according to a modified up‐down protocol (40 V up, 20 V down). When a T wave stimulus induced VF, a defibrillation stimulus was delivered 10 seconds later, also according to the modified up‐down protocol. Exponential, logistic, log‐dose logistic, piecewise linear, and Box‐Tiao dose‐response curves were fit to the resulting data using the maximum likelihood method. For the defibrillation data, it was found that only the logistic and Box‐Tiao curves fit all of the animals (P < 0.05). For VF induction, only the Box‐Tiao curve fit all of the animals (P < 0.05). Extrapolating along a dose‐response curve that did not fit to a shock strength with a very low probability of inducing VF or a very high probability of defibrillating yielded errors as great as 610 V. Conclusion : The Box‐Tiao dose‐response curve is the best single choice for fitting VF induction or defibrillation datasets