The proceedings and records of a review committee shall be held in confidence and shall not be subject to discovery or introduction into evidence in any civil action against a professional health care provider arising out of the matters which are the subject of evaluation and review by such committee and no person who was in attendance at a meeting of such committee shall be permitted or required to testify in any such civil action as to any evidence or other matters produced or presented during the proceedings of such committee or as to any findings, recommendations, evaluations, opinions or other actions of such committee or any members thereof: Provided, however, That information, documents or records otherwise available from original sources are not to be construed as immune from discovery or used in any such civil action merely because they were presented during proceedings of such committee, nor should any person who testifies before such committee or who is a member of such committee be prevented from testifying as to matters within his knowledge, but the said witness cannot be asked about his testimony before such a committee or opinions formed by him as a result of said committee hearings.