Q.why EF can be noramal or inc in RCM?

[Anand999]

Q. In restrictive cardiomyopathy (RCM), heart neither contracts nor relaxes normally.So, I was thinking ejection fraction should obviously decrease. But, when I was reading MTB , it’s mentioned that EF may be normal or elevated in RCM.How is this possible, can anyone explain this. Thanks.

[Dr.Ali129]

Hello bro,

If you look backwards you will find it out yourself.
RCM means what??
EF= what ??

RCM means stiff muscle that lost its elasticity ... meaning it can't stretch or contract properly
EF = (EDV - ESV)/ EDV ... please double check all these equations "HIGH YIELD!!"

,so if cardiac muscle can't stretch enough during diastole and can't contract enough during systole >>> definitely EF will change ....... but towards what?
always if you see restrictive ... think STRETCH is decreased more...meaning that cardiac ability to accept blood is decreased far more than the decrease in contraction.

If we translated this into the equation >>> the decrease in EDV is MORE than the decrease in ESV
For example if we put some numbers for simplification:
EDV =120 ... if decreased it will be 100 "(-20)>>> more decrease"
ESV = 40... if decreased it will be 30 "(-10)>>> less decrease"

EF in normal = (120-40)/120 =80/120 =.6666 >>> roughly equals 67%
EF in RCM = (100-30)/100= 70/100 = .7 >>> 70%

***Hints,
- EF usually decreased in systolic dysfunction rather than in diastolic dysfunction... "as in HF"
- This explanation "with some slight modifications" gives answer to why EFV1/FVC is increased in restrictive lung disease.

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Hope it helps
Kindly anyone correct any wrong info here ... no one is perfect
Wish you the best ... and wish me the best too

[Anand999]

Thanks Dr. Ali129 for explaining everything clear with Egs.