[Late tamponade after heart surgery: a dreadful diagnostic pitfall].

In a series of 250 consecutive open-heart operations, three cases of late cardiac tamponade were noted following the operation. This led the authors to review the literature pertaining to this complication. Ninety-nine cases were collected. The frequency of late tamponade associated with cardiac surgery was 0.62% and was fatal in 16.2% of those cases. The delay before the tamponade appeared varied from 3 days to 3 months (mean 14.5 +/- 7.8 days). The initial clinical picture is insidious and vague, and this constitutes the danger of late cardiac tamponade. The clinical signs are of the respiratory (dyspnea, chest pain), gastrointestinal (anorexia, vomiting) and central nervous (mental confusion, even coma) systems. Pallor with a drop in hematocrit in patients on anticoagulant therapy suggests occult bleeding. A definitive diagnosis depends on catheterization of the right side and on mono- and bidimensional echocardiography. The authors believe that computerized axial tomography represents an interesting noninvasive and reliable examination technique when it can be used during emergency treatment. Pericardial puncture, which is both a diagnostic and therapeutic technique, was useful in one third of the cases; it produced a false-negative result in 12%. The resulting differential diagnoses are pulmonary embolism, myocardial insufficiency and septic shock. Late cardiac tamponade may be produced by one of two mechanisms: hemopericardium due to overdosage of anticoagulants or an exacerbated form of the post-pericardiotomy syndrome. Emergency treatment is always necessary. Pericardiocentesis is a useful diagnostic aid and provides temporary stabilization preoperatively. A wide surgical approach is always indicated. The mortality in untreated patients is 100%. The frequency of immediate relapse or, occasionally, of delayed relapse is estimated to be 11%; relapse may be lethal.