Increased Dispersion of Atrial Refractoriness Predicts Most of the Inappropriate Implantable Cardioverter-Defibrillator Shocks - Abstract
Background: Despite implantable cardioverter-defibrillators’ proven survival benefits, inappropriate shocks limit their benefits due to adverse effects on quality of life, potential arrhythmogenesis, and even mortality. Atrial fibrillation (AF) is the most common cause of inappropriate shocks. Therefore, to predict and treat AF may prevent inappropriate shocks and their hazardous potentials. This paper aimed to show that we could predict the patients who may experience inappropriate implantable cardioverter-defibrillator shocks by measuring atrial refractoriness. Methods: 186 consecutive patients who underwent initial ICD implantation underwent coronary angiography and electrophysiologic (EP) study before the ICD implantation. Results: Of 169 patients who could be followed, 34 received (20%) at least one inappropriate shock during the mean follow-up of 30 months. The
majority of these shocks were due to AF (68%). The most significant predictors for these inappropriate shocks were atrial effective refractory periods (AERPs) and AERP dispersion. Conclusions: We found that simple EP study parameters measuring atrial refractoriness may define the patients carrying higher risk for future inappropriate shocks due to AF. We could prevent inappropriate shocks and hazardous results in these patients by either device programming, pharmacological treatments, or ablation procedures.