Long-term follow-up of idiopathic chronic pericardial effusion.

Background: A large idiopathic chronic pericardial effusion is a collection of pericardial fluid that persists for more than three months and has no a pparent cause. We conducted a prospective study of the natural history and treatment of this disorder. Methods: Between 1977 and 1992, we prospectively evaluated and enrolled pat ients with large idiopathic chronic pericardial effusion. We performed peri cardiocentesis in most of the patients. We performed pericardiectomy when l arge pericardial effusion reappeared after pericardiocentesis. Follow-up ra nged from 18 months to 20 years (median, 7 years). Results: During the study period, we evaluated a total of 1108 patients wit h pericarditis, 461 of whom had large pericardial effusion. Twenty-eight of these patients (age range, 7 to 85 years; median, 61) had large idiopathic chronic effusion and were included in the study. The duration of effusion ranged from 6 months to 15 years (median, 3 years). At the initial evaluati on, 13 patients were asymptomatic. Overt tamponade was found in eight patie nts (29 percent). Therapeutic pericardiocentesis, performed in 24 patients, was followed by the disappearance of or marked reduction in the effusion i n 8. Five of the 24 patients underwent early pericardiectomy, and in 11 lar ge pericardial effusion reappeared. Cardiac catheterization, performed in 1 6 patients, showed elevated intrapericardial pressure (mean [+/-SD], 4.75+/ -3.79 mm Hg) and reduced transmural pressure (1.0+/-2.50 mm Hg) before peri cardiocentesis. Both of these abnormalities in pressure improved significan tly after pericardiocentesis. Pericardiectomy, performed in 20 patients, yi elded excellent long-term results. At the end of the follow-up period, 10 p atients had died, but none had died from pericardial disease. Conclusions: Large idiopathic chronic pericardial effusion is well tolerate d for long periods in most patients, but severe tamponade can develop unexp ectedly at any time. Pericardiocentesis alone frequently results in the res olution of large effusions, but recurrence is common and pericardiectomy sh ould be considered whenever a large effusion recurs after pericardiocentesi s. (N Engl J Med 1999;341:2054-9.) (C)1999, Massachusetts Medical Society.