Merck has been cleared of responsibility in the heart attack of a former Vioxx patient in the 10th case to go to trial over the withdrawn painkiller.The latest verdict brings the trial tally to five wins and four losses for Merck. A new trial was granted for the remaining verdict in New Jersey last month, following the emergence of new data in that case. In the latest case, a federal jury in New Orleans ruled Merck had adequately warned of Vioxx’s heart risks and stated that Vioxx wasn’t the cause of the heart attack of Robert Smith, 56, of Florence, KY.Merck withdrew Vioxx from the market after a study linked the drug to heart risks two years ago this week.