Clinical experience with a novel electromyographic approach to preventing XXXX during cryoballoon ablation in atrial fibrillation.

@entity129 @entity1 @entity128
BACKGROUND: @entity129 remains the most frequent complication associated with cryoballoon-based pulmonary vein (PV) isolation. We sought to characterize our experience using a novel monitoring technique for the prevention of @entity129 . METHODS AND RESULTS: Two hundred consecutive cryoballoon-based PV isolation procedures between October 2010 and October 2013 were studied. In addition to standard abdominal palpation during right phrenic nerve pacing from the superior vena cava, all @entity1 underwent diaphragmatic electromyographic monitoring using surface electrodes. Cryoablation was terminated on any perceived reduction in diaphragmatic motion or a 30% decrease in the compound motor action potential (CMAP). During right-sided ablation, a >= 30% reduction in CMAP amplitude occurred in 49 @entity1 (24.5%). Diaphragmatic motion decreased in 30 of 49 @entity1 and was preceded by a 30% reduction in CMAP amplitude in all. In 82% of cases, this reduction in CMAP amplitude occurred during right superior PV isolation. The baseline CMAP amplitude was 946.5  609.2 mV and decreased by 13.8  13.8% at the end of application. This decrease was more marked in the 33 PVs with a reduction in diaphragmatic motion than in those without (40.9  15.3% versus 11.3  10.5%; P<0.001). In 3 cases, @entity129 persisted beyond the end of the procedure, with all cases recovering within 6 months. Despite the shortened application all veins were isolated. At repeat procedure the right-sided PVs reconnected less frequently than the left-sided PVs in those with @entity129 . CONCLUSIONS: Electromyographic phrenic nerve monitoring using the surface CMAP is reliable, easy to perform, and offers an early warning to impending @entity128 .
