External cardioversion of atrial fibrillation in patients with implanted pacemaker or cardioverter-defibrillator systems: a randomized comparison of monophasic and biphasic shock energy application

Abstract

ECV for AF seems to be safe and effective in patients with implanted rhythm devices.

External defibrillation on an implantable defibrillator

“…A less deleterious effect might be expected if the orientation of the applied electric field is perpendicular-and not parallel-to the device with its lead(s), whereas if the device is located in the left pectoral region, an anteriorapex paddle position may be also acceptable. With an anterior-posterior electrode orientation and a distance between device and hand-held shock electrode of [8 cm, Manegold et al [3] did not observe any dysfunction in patients with right-or left-sided implanted pacemakers or ICDs treated with external cardioversion for atrial fibrillation.…”

Implanted Devices and Atrial Fibrillation

“…First of all, electricity conducted along an implanted electrode may cause endocardial injury and bring to a temporary or permanent increase in stimulation threshold, resulting in acute or chronic loss of ventricular capture. Moreover, other ECV related problems include physical dysfunction of the device, spurious programming or electrical reset induced by the shock and changes in sensing function or pacing impedance [31,32]. Table 2.…”

“…For AF duration and cumulative shock energy, the median values and range are provided. Adapted from [31].…”

“…The positioning of paddles at least 8 cm away from pulse generator [31] did not produce changes in pacing thresholds or sensing measurements, preferably in the anterior-posterior configuration, as specified in AHA Guidelines [33]. The best paddles configuration is the anterior-posterior one.…”

Electromagnetic Interference of the Pacemakers

“…In addition, CV has evolved over recent years with the development of equipment able to deliver biphasic shocks resulting in an increased efficacy and lower energy requirements. Manegold et al, 2007 studied 29 patients with pacemaker undergoing elective external cardioversion for atrial fibrillation, using an anterior-posterior shock electrode orientation with a distance to the implanted device ≥ 8 cm. He noted that there is reduction of the pacing impedance immediately after the cardioversion.…”