ET has learned exclusively that Kelsey Grammer has been hospitalized in New York and has cancelled four television appearances because of an irregular heartbeat. The actor, who was in town to promote ‘Swing Vote,’ began feeling faint. Kelsey checked into the hospital and is being treated for an irregular heartbeat, which we’ve learned could be a result of medication he was taking for his recent heart attack.

ET has been told that the medication has now been modified and Kelsey will remain under observation for one more day.