Low-energy shocks resulted in a higher frequency of postdefibrillation ventricular arrhythmias with a cycle length <= 300 msec compared to high-energy shocks (19% vs 1.5%; P=0.005).
Does shock energy influence the frequency and cycle length of postdefibrillation ventricular arrhythmias in patients with implantable defibrillators?
Low-energy shocks are associated with faster postdefibrillation ventricular arrhythmias (cycle length <= 300 msec), whereas high-energy shocks are associated with slower arrhythmias (cycle length > 300 msec).
Tasa de eventos absoluta: 19% vs 1.5%
valor p: p=0.005
BACKGROUND: The relationship between postdefibrillation ventricular arrhythmias and shock strength is poorly understood in patients with implantable defibrillators. The purpose of this study was to characterize the relationship between postdefibrillation ventricular arrhythmias and shock strength. METHODS AND RESULTS: Forty-three patients with an implanted defibrillator underwent six separate inductions of ventricular fibrillation (VF) after a step-down defibrillation energy requirement (7.3 +/- 4.6 J) was determined. For each of the first three inductions of VF, the first two shocks were low energy and equal to approximately 75% of the defibrillation energy requirement (5.4 +/- 3.3 J), or to the defibrillation energy requirement plus 10 J (17.5 +/- 4.3 J). After the first two shocks, subsequent shocks were programmed to the maximum available energy (29.0 +/- 2.5 J). The alternate technique was used for the subsequent three inductions of VF. Postdefibrillation ventricular arrhythmias were noted. Postdefibrillation ventricular arrhythmias with a cycle length 300 msec were uncommon after shocks 300 msec are more common after high- and maximum-energy shocks, and are directly related to the absolute defibrillation energy.
Zivin et al. (Mon,) conducted a other in Ventricular fibrillation (n=43). Low-energy shock vs. High-energy shock was evaluated on Postdefibrillation ventricular arrhythmias with a cycle length <= 300 msec (p=0.005). Low-energy shocks resulted in a higher frequency of postdefibrillation ventricular arrhythmias with a cycle length <= 300 msec compared to high-energy shocks (19% vs 1.5%; P=0.005).