Impedance compensated biphasic waveforms for transthoracic cardioversion of atrial fibrillation: a multi-centre comparison of antero-apical and antero-posterior pad positions

Abstract

The influence of pad position for DCC of AF may be less pertinent with ICB waveforms than with monophasic waveforms.

Association between transthoracic impedance and electrical cardioversion success with biphasic defibrillators: An analysis of 1055 shocks for atrial fibrillation and flutter

“…Though our data are from a single center, the considerable variability in starting energy and shock energy escalation suggests nonuniform practices, which is consistent with the variability in ECV techniques seen at other centers . Furthermore, our findings were similar in sensitivity analyses restricted to patients who received ≥150 J for their first shock, which has been the suggested starting energy by others . We used data from biphasic truncated exponential (BTE) waveform defibrillators only.…”

“…Contemporary defibrillators deliver biphasic shocks and modify their waveforms in response to the measured TTI. Indeed, in contrast to studies using monophasic shocks, 2 publications reporting on biphasic waveforms in patients with ventricular tachyarrhythmias found that TTI was not predictive of shock success …”

“…TTI was divided into quartiles for these analyses. Given the possibility that differences in starting energy and shock energy escalation could influence outcomes, a sensitivity analysis restricted to patients who received a first shock of ≥150 J was performed, as this starting energy has been recommended by others and has been associated with ECV success rates of ≥80% . Simple and multivariable logistic regression models were fit to estimate the influence of TTI on last‐shock success, first‐shock success, the need for ≥3 shocks, and cumulative energy delivery in the top quartile of the AF cohort.…”

“…TTI has long been considered an important predictor of ECV success by influencing the current fraction that reaches the myocardium . However, though strategies to modify TTI during ECV attempts continue to be endorsed in current guidelines, its importance in the era of impedance‐compensated biphasic defibrillators is unclear, with some data suggesting that its influence may be negligible . We therefore sought to explore the relevance of TTI on AF and AFL ECV success using contemporary defibrillators.…”

Biphasic energy selection for transthoracic cardioversion of atrial fibrillation. The BEST AF Trial

“…This position is the most widely used in clinical practice and has been previously shown to be as effective as anteroposterior pad positions when using an impedance-compensated biphasic waveform 15. The transthoracic impedance for each shock was recorded by the defibrillator.…”