 If the internal pilot phase is positive, all the patients will be rolled-over into the full-scale IMPI trial. The first occurrence of death will be recorded to improve estimates of outcomes for the full-scale trial. Secondary outcomes of the full-scale trial will include: 1 constriction, 2 rate of occurrence of cardiac tamponade requiring pericardiocentesis, 3 rate of resolution of pericardial effusion, 4 improvement in functional class. 