Sedation for catheter ablation of atrial fibrillation should be performed to achieve analgesia, immobilization, and maintenance of airway. Various anesthetic agents such as propofol, dexmedetomidine, and midazolam were investigated to achieve this goal. However, propofol and midazolam causes respiratory depression and dexmedetomidine occasionally accompanies hypotension or hypertension and bradycardia. Therefore, anesthetic agent that does not induce respiratory depression with stable hemodynamics is needed.

Propacetamol (Denogan®, Yungjin, Seoul, Korea) is injectable prodrug of acetaminophen and 1st line drug for fever and pain. In a previous study, paracetamol reduced morphine consumption after surgery. And paracetamol does not cause respiratory depression. Thus, the investigators hypothesized that addition of propacetamol to previously used sedatives midazolam-remifentanil will reduce opioid consumption during the catheter ablation.

Therefore, the investigators designed this study to investigate the role of addition of propacetamol to previous used midazolam-remifentanil sedation. This study will compare the opioid consumption and respiratory effect of propacetamol with placebo-control for catheter ablation of atrial fibrillation.

Inclusion Criteria:

• patients who are scheduled to undergo catheter ablation for arrhythmia

Exclusion Criteria:

• Subjects are ineligible if they have liver disease, kidney disease,
• American society of anesthesiology class 3 or 4,
• age under 20 years,
• cognitive dysfunction,
• disabling mental change disorder,
• patients are unable to communicate or speak Korean