It sounds like your family has had a tough time dealing with this, and unfortunately chronic pericardial effusions can be quite difficult to treat. Steroids can be very helpful in treating this condition, which in most cases, are idiopathic in origin (or presumed from some viral inflammation of the tissues). There would be no specific referral center for this type of problem; all pediatric cardiologists have to deal with this at some time, and the more patients that are seen at an institution, the more likely they will have had experience with a variety of cases of pericardial effusions. The timing of doing a pericardial window is an individualized process, and if the patient is stable, one could certainly wait at least 3 months or more to see if the patient is proving to fail all medical therapy. Remember the pericardial window just drains the fluid out of the heart sac so there is no tamponade effect; the fluid then goes into the pleural space, but it is a safer situation. If you are seeking a second opinion, it would probably make sense to go to one of the largest centers near to where you live. You can check US News & World report ranking of the top 10 pediatric cardiology programs in the country. You would do well at any one of those. Good luck.