Dr.S.Venkatesan MD

Constrictive pericarditis is a well known mechanical disorder  of heart that occurs due to the  compression  by thickened pericardium .Constrictive pericarditis is  the classical cause for  severe diastolic dysfunction.

We know , lungs are   prone for restrictive disorders due to chest wall , skeletal  disorders. Does the heart get mechanically restricted in extreme obesity ?

Not really , one may reason out . Chest wall fat can have little effect on cardiac function but when excess fat accumulates within the layers of heart , it is indeed possible for  the  fatty layer to impede mechanical filling of heart. This may be considered rare as of now , but many times it is not recognised ,  as most of the dyspnea in morbid obesity is attributed to some other known factors.

Dyspnea in obestity  can  due to

• Pulmonary hypoventilation
• Increased  MVO2 due to elevated cardiac mass
• Diastolic dysfunction of  LV/RV
• Increased demand  due to  excess BMI.

Image courtesey : http://www.onlinejacc.org

Now, we have evidence for  altered RV hemodynamics due to compressing effect  of epicardial fat pad. It may be due to   simple mechanical effect  of epicardial  fat over the distensiblity of RV or occasionally  LV. (The distribution of epicardial fat is mainly over the right ventricle or septal areas.)

This   paper  from Korean circulatory journal  succinctly describes this new possibility .

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2771803/pdf/kcj-39-116.pdf

Final message

Bed side cardiology  continues to  bring surprises  , it  never fails to fascinate us   !

Heart  is  a dynamic organ ,  has a potential to get restricted by  any  layer that  surrounds  it. Constriction by pericardium got huge attention so far .We need to realise , the epicardium which is  a part of pericardium has a variable fat depot  . It  can take a different avatar  in an occasional obese individual  and   exert  important hemodynamic impact.

Excess fat is excess load on heart . . .  we have  to unload it

It is possible , sucking out the  epicardial  fat in morbid obesity can bring important relief to  those patients with unexplained dyspnea . We  need to  explore this possibility.