Charlie McAvoy, one of the NHL’s best rookie defensemen, will be out at least two weeks following a procedure for an abnormal heart rhythm yesterday at Massachusetts General Hospital. McAvoy was monitored overnight and likely will watch from the ninth floor of the Garden tonight when the Bruins face the New Jersey Devils. McAvoy had concerns about heart palpitations he experienced during a game in late November. The Bruins medical staff felt the procedure was the proper course of action. “Subsequently, he underwent an evaluation which diagnosed him with a supraventricular tachycardia (SVT),” team physician David Finn said in a statement. “The type of SVT Charlie has is not to be considered dangerous to his health, but it may occur at any time and cause significant symptoms.” The procedure was called an ablation and is recommended “due to a high probability of recurrence,” Finn said. The normal recovery time is two weeks. The Bruins are fortunate that four of McAvoy’s recovery days will coincide with the NHL All-Star break. McAvoy sees most of his action paired with captain Zdeno Chara and is routinely matched against the opponent’s top line. He is averaging 22:48 of ice time, the most among NHL rookies. McAvoy is sixth on the team in scoring with 25 points (five goals, 20 assists) and has a plus-18 rating.