Background: A large idiopathic chronic pericardial effusion can be defined as a collection of pericardial fluid that persists for more than three months and has no apparent 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 patients with large idiopathic chronic pericardial effusion. We performed pericardiocentesis in most of the patients. We performed pericardiectomy when large pericardial effusion reappeared after pericardiocentesis. Follow-up ranged from 18 months to 20 years (median, 7 years).
Results: During the study period, we evaluated a total of 1108 patients with 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 evaluation, 13 patients were asymptomatic. Overt tamponade was found in eight patients (29 percent). Therapeutic pericardiocentesis, performed in 24 patients, was followed by the disappearance of or marked reduction in the effusion in 8. Five of the 24 patients underwent early pericardiectomy, and in 11 large pericardial effusion reappeared. Cardiac catheterization, performed in 16 patients, showed elevated intrapericardial pressure (4.75+/-3.79 mm Hg) and reduced transmural pressure (1.0+/-2.50 mm Hg) before pericardiocentesis. Both of these abnormalities in pressure improved significantly after pericardiocentesis. Pericardiectomy, performed in 20 patients, yielded excellent long-term results. At the end of the follow-up period, 10 patients had died, but none had died from pericardial disease.
Conclusions: Large idiopathic chronic pericardial effusion is well tolerated for long periods in most patients, but severe tamponade can develop unexpectedly at any time. Pericardiocentesis alone frequently results in the resolution of large effusions, but recurrence is common and pericardiectomy should be considered whenever a large effusion recurs after pericardiocentesis.