Dr.S.Venkatesan MD

Even though cardiologists consider themselves master of ischemic heart disease , their collective clinical acumen is  put into  acute stress test   when they  confront  a patient with dilated LV and severe  LV dysfunction.This is not  a  rare situation  in clinical cardiology we stumble upon such instances often .Most of them are conferred a  tag  of DCM .

The differentiation from ischemic  vs idiopathic or primary muscular is not a  wasted academic exercise  , since   ischemic  DCM  may get reversed with revascularisation .We have  various  tests to differentiate  ischemic from idiopathic like CAG,MRI, 3D RTE, etc . Still common sense would tell us   95 % of times we can  differentiate ischemic DCM from non ischemic by asking  two critical questions  in the  bed side  echocardiogram

1. Is there a regional wall motion defect ?
2. Does all 4 chambers of the heart is enlarged ?

Idiopathic DCM is primary disease of muscle hence  the cardiac   muscle as a  whole  fails  ( We know they are a single  folded  muscle sheet )

Since  Ischemic DCM  primarily affect left ventricle and left atrium  RV,RA enlargement  are terminal events.

* Please note the traditional dependence on CAG to  diagnose  ischemic DCM is fraught with a risk of missing small vessels  induced  DCM,

*** If atrial fibrillation is present longstanding it can dilate both atrium but still RV will be normal  in sized in  ischemic DCM until very late stages

Here is a  20  second flow  chart  to differentiate ischemic  DCM  from idiopathic