Key result
Elective cardioversion synchronized to VVI pacemaker pulses triggers VF via an ST segment shock.
Why the study?
The risk and mechanism of ventricular fibrillation following elective cardioversion in patients with permanent pacemakers require clarification.
Case Report (n=1)
Elective cardioversion in patients with pacemakers in asynchronous (VOO) mode carries a risk of inducing ventricular fibrillation if the cardioverter synchronizes to the pacemaker output pulses.
Pacemaker mode conversion before cardioversion requires vigilance to avert VF; this Level 5 case leaves open standardized safety protocols.
Elective cardioversion was undertaken in a patient with a VVI pacemaker and atrial tachyarrhythmia after converting the pacemaker to a VOO mode of function. The cardioverter output energy was unwittingly synchronized to the pacemaker output pulses that were falling randomly in various portions of the cardiac cycle. This resulted in the cardioverter DC shock being discharged in the ST segment of the native QRS with consequent ventricular fibrillation.
No takes yet. Share an insight, caveat, or question.
Vera et al. (1990) conducted a case report in Atrial tachyarrhythmia with a VVI pacemaker (n=1). Elective cardioversion synchronized to pacemaker output pulses was evaluated on Ventricular fibrillation. Elective cardioversion synchronized to pacemaker output pulses in a patient with a VVI pacemaker resulted in a DC shock during the ST segment, causing ventricular fibrillation.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: