Dynamic effects of pericardial effusion without tamponade. Respiratory responses in the absence of pulsus paradoxus.

Fourteen patients with pericardial effusions without clinical signs of tamponade (pulsus paradoxus or other cardiac and circulatory abnormalities) showed inspiratory reductions in echocardiographic left ventricular internal diastolic diameter which correlated directly with the exaggerated respiratory changes in systolic time intervals (both pre-ejection period and left ventricular ejection time). Excessive pericardial fluid affects left ventricular function even in the absence of clinical manifestations.