Two hours after the first dose of study drug is given a 12-lead ECG will be recorded and interpreted by the study physician. For patients initiating flecainide the PR interval and QRS duration will be carefully scrutinized. If these remain unchanged, the patient will be discharged from the CRC. For patients initiating sotalol, the QTc will be examined. If the duration is >500 ms, the sotalol dose will be reduced to 80 mg by mouth twice daily. Patients initiating sotalol will be admitted for continuous telemetric monitoring and will remain in the CRC until after the 5th dose is administered. Additional 12-lead ECGs will be obtained two hours after the 3rd and 5th doses of sotalol to assess QTc. If the duration remains >500 ms on the reduced (80 mg) dose of sotalol, the drug will be stopped and the patient will be removed from the study. If the QTc remains ≤500 ms after the 5th dose of sotalol, the patient will be discharged from the CRC.