Can lower heart rate alone improve ejection fraction?

[Tinu1959]

A heart ischemic heart attack in 2007 left me with an ejection fraction of 35-38% which has come down to 30% over a period of time. I have blocked LCx (not opened), and LAD opened with a stent. RCA is good. There are other minor blockages which doctors say are not significant for putting a stent. The heart area receiving blood from LAD is non-functional (akinitic).

My resting heart rate was 80+ until one and a half year after MI when I was taking higher dose of betablocker (carvidilol) 36 mg daily and EF had come down to 30% (from 35-38% after MI).

For last six months since I was advised by a new cardiologist to bring down carvidilol to 25 mg daily, my haert rate has come down to 65+. My BP had remained 105-110/70. I take 5 mg daily ramipril (ACE Inhibitor). Physically I feel better after I reduced betablocker.My EF has remained at 30% (no improvement) even now.

My question is, whether I can expect any improvement in EF with the crrent heart rate (65+) . Will reducing betablocker further will bring down my heart rate or help in improving my EF?
I have been adviced for slow daily walk of 30 minutes which takes my HR to only 90 bpm. Will it help increasing HR, say to 110 bpm by walking briskly??


Thanks

Narender

[kenkeith]

Theraputically beta blockers for heart patients slow and stabilize the heart rate and  this enables more time for diastole as fast beating heart has less time to fill and may present a overcompensation in other aspects of the cardio/vasculatory system.  Also, some beta blockers dilate vessels providing less stress to heart.

If you heart overcompensated by dilating (left vertricle) this condition would reduce your EF.  If medication  is effective, it will reduce the heart's workload and the heart could reverse its remodeling.  To reduce your beta blocker could add a burden that would decrease the EF.

QUOTE: "The heart area receiving blood from LAD is non-functional (akinitic)".  Akinetic indicates necrotic (dead) cells.  If I understand the quote, the LAD fails to provide adequate blood to heart cells in question and cells have died.  If that is true, you may have to live with reduced EF until stem cell therapy is available and applicable to your situation.  Many people function satisfactorily with a reduced EF and medication.

[ed34]

I think you have it the wrong way around. Beta blockers reduce the Heart rate, the more you take, the less the Heart can work. Decreasing beta blocker dosages should raise your heart rate, allowing it to work harder. The risk of reducing beta blockers is that you
will allow your heart to work too hard for its own good, causing more damage.
Ejection fraction is calculated by.....
measuring the  volume of blood within a ventricle immediately before a contraction (end-diastolic volume). The volume of blood left in a ventricle at the end of contraction is end-systolic volume. The difference between end-diastolic and end-systolic volumes is the stroke volume, the volume of blood ejected with each beat. Ejection fraction (Ef) is the fraction of the end-diastolic volume that is ejected with each beat;  it is stroke volume divided by end-diastolic volume. Normal in a man is 50-68%.
With a given sized ventricle and its volume, and its ability to contract, I fail to see how a
faster or slower heart rate will affect the volume of blood leaving the chamber. If the heart
pumps faster, the volume leaving the ventricle will always be the same. The
only way to improve or worsen the EF is to increase/decrease the muscle strength.
If heart muscle is damaged in a ventricle then this will lower EF because it has less muscle to work with. Speeding it up will increase blood flow, but not EF and this will
possibly cause further heart damage.