Use of trancutaneous CO2 (TC02) monitoring to aide in titration of sedation of midazolam and fentanyl. Trancutaneous readings validated with invasively obtained specimens from existing arterial sheaths required during AF and VT ablations (trans-septal and retrograde aortic respectively)

Cardiac electrophysiology procedures are typically performed under moderate (conscious) sedation in most centers. Advantages over general anesthesia include facilitating arrhythmia induction, avoidance of intubation and ventilator related complications and shorter post-procedure recovery times for most patients. However, the cumulative respiratory depressant effects of fentanyl and midazolam during prolonged procedures can rarely cause hypoventilation resulting in hypercapnea and respiratory failure. Complex catheter ablations for atrial fibrillation and ventricular tachycardia can exceed 3-5 hours in duration requiring large cumulative doses of midazolam and fentanyl. End tidal CO2 monitors, particularly in non-ventilated patients, have limitations and obtaining frequent arterial blood gas samples are often impractical. It remains unknown if contemporary trancutaneous CO2 monitoring (TCO2)can provide a feasible alternative to avoid over-sedation and resultant respiratory complications during complex catheter ablations with sufficient agreement to invasively obtained PCO2 data.

Inclusion Criteria:

• Patients undergoing catheter ablation for atrial fibrillation (AF) or ventricular tachycardia (VT) under moderate sedation.

Exclusion Criteria:

• Procedures scheduled for general anesthesia

Patients undergoing catheter ablation for artial fibrillation or ventricular tachycardia