A novel method for phrenic nerve monitoring during cryo-balloon procedures

Cryo-balloon ablation is associated with a consistent risk of phrenic nerve damage. Currently, only the diaphragmatic compound motor action potential (CMAP) has been shown to be effective in preventing this complication.

evaluate the diagnostic performance of a new surface electrodes positioning, named NeedMAP, using CMAP as the gold standard.

150 patients underwent cryo-balloon ablation. During the procedure we placed the CMAP leads as per manufacturer indication and our alternative method by placing ECG electrodes on the anterior axillary line. We simultaneously recorded the CMAP and the NeedMAP.

A total of 438 cryo-balloon applications were performed on the right pulmonary veins. The mean value of CMAP amplitudes were 0.60±0.33mV, whereas the NeedMAP were 0.85±0.46mV (p < 0.001). 15 patients (10%) showed a nerve threat. We found that in our population the CMAP, on regards of nerve damages, had a sensitivity of 38% and specificity of 76%. The NeedMAP showed a sensitivity of 61% and specificity of 86%.

The NeedMAP signals for PN monitoring during cryo-balloon ablation seems a reliable method, showing good sensitivity, specificity and can help clinician for preventing phrenic nerve damage.Figure 1  Figure 2