Ejection Fraction

My question is whether or not a low EF% always suggests heart failure?

I ask because many members with SSS and / or AVB post on here to say that their low EF% improved with pacing to a normal %EF. I note that many do not mention a prior heart failure diagnosis. 

Can SSS and/or AVB alone cause a low EF % or does a low EF% always suggest that there is a heart failure component? 




My thoughts on ejection fraction

by Gemita - 2023-08-15 08:47:47

Hello Penguin, welcome back.

No a low ejection fraction doesn’t always suggest, at least to me, irreversible heart failure, especially if it is borderline low or clearly caused by another treatable condition.

Heart block may lead to, or worsen heart failure if it is not treated, as can sick sinus syndrome.  Sick sinus syndrome may lead to heart failure if the patient develops fast uncontrolled arrhythmias for example which cause cardiomyopathy.

Many members report an improvement in their ejection fraction following upgrade of their pacemakers to CRT and they regard their heart failure as “reversed” when their ejection fraction returns to a normal range.  The ability to reverse heart failure depends on the cause of the heart failure, for example high blood pressure, heart valve problems, an arrhythmia.  Treat these conditions and our ejection fraction may return to normal.  

Some underlying causes of heart failure, like myocarditis due to an infection, or stress-induced cardiomyopathy, generally resolve over time, returning the heart pumping function to normal.

When someone has heart failure because of coronary artery disease, sometimes heart failure can improve with revascularization of the coronary artery blockages.  This is what my husband found.  Early diagnosis and early treatment of heart failure is important, because if the underlying cause isn’t addressed in time, it can cause long-term changes to the heart that make heart failure harder to reverse.

So can SSS and/or AVB alone cause a low ejection fraction, I would suggest “yes” if we don’t receive timely treatment to improve the pumping action of our hearts, but a low ejection fraction doesn’t “always” suggest a heart failure component since operator technique/experience, medication, lifestyle and other factors can all affect ejection fraction.   I am also aware that Echocardiogram results may vary - transthoracic vs transesophageal imaging, positioning issues, body habitus variables, so I don't worry about those numbers if they are not significantly changed.


by Penguin - 2023-08-15 10:21:39

Thank you for your thoughts Gemita. 


by Lavender - 2023-08-15 21:36:39

Can SSS and/or AVB alone cause a low EF % or does a low EF% always suggest that there is a heart failure component? 

My AV node block caused a low EF. It completely recovered to normal with the CRT-P. I'm not on any meds and was told that I was fixed. According to the heart association: "Heart failure is a lifelong condition in which the heart muscle can't pump enough blood to meet the body’s needs for blood and oxygen. Basically, the heart can’t keep up with its workload."

 I don't think of myself as having heart failure in a pumping way-moreso a heart rhythm disorder. 

Lavender & Gemita

by Penguin - 2023-08-16 05:45:53

My experience is similar to yours Lavender but with an SSS diagnosis and the implantation of a normal dual chamber pacemaker to treat bradycardia.  My EF was around 30% prior to pacing and is now around 50%.   


by PacedNRunning - 2023-08-21 21:32:51

Many HF patients receive pacemakers called CRT just to help reverse or improve HF. So when you see posting of improved EF, it's becaue their device was placed specifically for HF therapy.   They try a combo of meds and CRT or 3 lead PM.  

CRTs - PaceNRunning

by Penguin - 2023-08-22 05:45:48

Thank you for your input PacedNRunning.

Yes I do know that CRTs are used for HF along with meds. 

I wonder how common improvement in EF% is without meds / CRT or a 3rd lead and with dual lead pacing alone.  Perhaps, as Gemita suggests, a low EF% can have any number of causes.  Remove the cause via pacing or in combination with other changes and function improves. 

Interesting question and perhaps we will never know

by Gemita - 2023-08-24 07:14:28

Penguin, I noticed you wondered how common improvement in EF is without medication or CRT.  

I don’t know how well or how quickly a low EF could recover without treatment or identification of the likely cause, but it clearly spontaneously happens sometimes.

My sister had an EF of just 16% almost two years ago.  She was deemed too weak to have a CRT-D procedure, so they decided to manage her sudden severe left ventricular dysfunction (heart failure) on medication which seemed to work to bring her EF up, although she refused to take all the recommended meds to protect her.

I can remember thinking at the time that she could easily have had a serious event with such a low EF and without protection from CRT pacing and/or a Defibrillator and yet I knew that intervention could carry some risks for someone so weak.   

Her experience shows that "minimal" medication alone and lifestyle changes (mainly control of stress) can sometimes work well to bring back a dangerously low EF.  Who knows what might have happened if they had rushed into an invasive procedure.  

They are still looking for a cause for her sudden heart failure which is a mystery to all of us.  She first presented with tachycardia, breathlessness to A&E.   They are now looking for scarring/damage to the heart from breast cancer radiation treatment. 

She was recently found to have pneumonia when they tried carrying out an MRI Cardiac Stress Perfusion test so this had to be abandoned unfortunately because she struggled with an increased heart rate, but at least the good news is that her ejection fraction has stayed recovered and she is still relatively well.

I don't think her team want to repeat the MRI unfortunately, although they reported that the aetiology of her LV impairment is still not as clear as they would like.  When questioned, they just say that because her ejection fraction is back to 43% now (according to MRI initial assessment without contrast), there was no compelling argument to repeat the scan.


by Penguin - 2023-08-24 13:05:22

Gemita, thank you for sharing your sister's story. 

I know very little about ejection fractions and was shocked to stumble upon my own results.  I remember my GP being really concerned at the time and describing my pulse as difficult to find on discharge from hospital, but a low EF% was never discussed with me.  I didn't shun all interventions / drugs at the time but they made things worse for me so it sounds like your sister was one step ahead of me!   

I think that sometimes we instinctively know that to leave well alone may help most.  Finding your voice in that situation isn't easy as the natural reaction is to intervene and who can blame medicine for doing so - it's their job to save and improve lives.

My doctors meant well and felt the danger for me.  Would you sister benefit from a CRT-D? Perhaps, but it's her choice not ours. 


You know you're wired when...

You trust technology more than your heart.

Member Quotes

A pacemaker completely solved my problem. In fact, it was implanted just 7 weeks ago and I ran a race today, placed first in my age group.