Horowitz classification of pericardial effusion

Detection of  pericardial effusion was  the earliest  clinical application of echocardiography. Diagnosing  large effusions is a non issue .Assessing  minimal effusions (Systolic vs diastolic echo free space) and associated  thickened pericardium is tough even after 50 years of echocardiography.

Mainly , we are limited by the resolution power of echo. Further , lack of echocardiographic landmark for visceral  layer of pericardium (It is same as epicardium !) makes  diagnosis of  thickened pericardium a real tough exercise.It is said , normal pericardium is less than 4mm .

Where to measure it ?  how to measure is still not clear.

Why differentiating  minimal  pericardial effusion from  thickened pericardium  is important ?

• Mild  pericardial effusion is  largely a benign finding in vast majority.
• But , even a minimally thickened pericardium  due to active inflammation  can be significant.
• Sticky pericardial effusion predispose to thickening and constriction.
• Early recognition of this dreaded pericardial pathology is essential to interrupt the inflammatory process.
• In CRF (With or without dialysis) even a  minimal pericardial  effusion can denote a dismal outcome .

Here is a link to Horowitz classification of mild  pericardial  effusion ...

It could help us understand, How thickened pericardium presents in echo. Of course, CT and MRI now have increased sensitivity for diagnosing  pericardial thickening.