Widened QRS Duration and QTC Interval

I had my PM implanted about a year ago for symptomatic 2:1 AV block and though I feel somewhat better am still suffering from severe othostatic hypotension. My BP is dropping up to 40 mm upon standing. While trying to get to the bottom of this Ive noticed my EKG numbers dramatically worsened after the pacemaker.

QRS 86 to 152 
QTC 428 to 502
PR   178 to 248
HR 70 bpm, leads -Apex placed, Dual paced 73 yo male. 97% paced

Im a little concerned as I just came across a few studies which found a correlation with all cause mortality and a delta QRS of just 43 ms. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9295034/

Anyone else have such a dramatic change in ekg numbers?   My main concern is reducing the symptoms of OH but of course the widened QRS is also a concern



by Lavender - 2023-07-22 01:20:49

We discussed this not long ago. Copy and paste this link:


I think that it's important to remember that if your cardiac team is not concerned, then things are not bad. My cardiologist told me that my wider QRS post pacemaker implant was nothing to worry about. It just took longer for the signal to get through. 

I guess you're still set at 70. Did you ask about making your low rate 60bpm? That's what most people have including me. 


by bob53 - 2023-07-22 13:42:41

Yes I read through that post and found it to be very helpful.  I'm also concerned about my long QTc interval over 500. .

Not to be a debby downer but Im not so sure a wider QRS complex is nothing to worry about. There are several pubmed studies including the one I linked to that shows it to be a very significant issue.

I hope Im wrong but sometimes doctors will tell us everthing is fine when they dont have an alternative. Why worry the customer. My new cardiologist I just saw last week didnt mention the long QRS either.

I would like to get my heart rate back down to 60. I plan to ask my EP at the next appointment and will see what he says. In the mean time Im using copious amounts of salt and drinking water to get my BP up. It seems to be helping.

I noticed from your bio you developed 2nd degree wenkebach during surgery, This is exactly what happened to me during my elbow surgery.





by Lavender - 2023-07-22 14:52:43

Bob, I can understand your concern. What has a pro told you about your numbers? Have you asked them about the statistics of folks with like situations?

 I like this Mayo article on this subject because it reads clearly. I wonder if any meds you're taking are contributing to the change in numbers?


Ok, so even if your mortality is threatened, what can be done to improve things?  I'm sure that worry is counterproductive. 😉

Talk with your cardiologist or EP and write down exactly what you're concerned about. See if they have a better explanation or solution.  My cardiologist basically said what it says in this pubmed article about long QRS:

Prolongation of ventricular repolarization, which is represented by QTc prolongation on the standard ECG can be considered as increased risk for fatal arrhythmia. However, in pacemaker dependency (with ventricular pacing from the right apex) Ventricular Pacemaker causes abnormal steps of ventricular activation and therefore widens QRS complex and alters ventricular repolarization. It is still questionable whether QTc prolongation in right ventricular-paced patients is associated with increased risk of fatal arrhythmia or other cardiac complications. 




by bob53 - 2023-07-22 15:30:21

Thanks for the helpful info and reply. Certainly worrying about something you cant effect is counter productive, but in this situation correcting a long QTc period is absolutely something that can be positively improved. As you mentioned prescription medicines are often the cause of prolonged QT and QRS intervals. One medicine Ive been on is well known to have this effect and Ive begun to taper off this for the past week. It also can cause orthostatic hypotension as well so Im hopeful this will address that issue too.

Unfortunately Ive found through experience that you cant always rely of the experts when it come to your own health needs. They dont have the time to deep dive into every issue that a patient presents with. I'll never know as much as them about medicine in general but when it comes to very narrow and specific areas of health, they can never spend the amount of time reading about it as we can. I think the combination of their overall expertise and our individual digging yields the best approach. The fact that not one of the many doctors Ive seen about my OH or arrythmias has mentioned that my  prescription could be an issue confirms this approach, to me at least.

Another thing to keep in mind is that its been said that it often takes up to 10 years for new research to hit clinical practice.

The research I posted is only from last year and given the extremely high hazzard ratio associated with a high delta in incremental QRS post ventrical pacing, I would question whether the Mayo clinic needs to update its article

"Delta increments in pacing QRS duration ≥ 43 msec [HR: 2.91; 95% CI: 1.23-6.83; p = 0.014] in patients with pre-existing RBBB, and ≥ 33 msec [HR: 11.44; 95% CI: 2.03-64.30; p = 0.006] in patients with pre-existing LBBB were independent determinants of CV mortality."


by Lavender - 2023-07-22 15:41:56

I would be cautious about lowering meds without dr supervision. One source of med information that I find especially helpful is my pharmacist. When in doubt about something that's been prescribed, I ask them about potential side effects etc. 

What we read online can sometimes present conflicting information. It can't replace a physician's education and experience. Our input helps them make decisions better. You have a new cardiologist. Call and speak to their staff about your thoughts on the medication affecting your OH. 

I agree

by bob53 - 2023-07-22 16:01:34

I agree with always running it by our doctors and have done so prior to tapering off the suspect med Im on. 

My point isnt that we can replace our doctors but only that its in our best interest to "supplement" them.


by AgentX86 - 2023-07-22 19:53:12

"but when it comes to very narrow and specific areas of health"

You really have to be careful with this one. While this may be true for things tangential to their specialty (e.g. pacemaker settings), I'd agree, some.  With issues like you're describing, you're right in the wheelhouse of a cardiologist's, or at least an EPs specialty. Dr. Google isn't going to do you any favors.

If you don't like the treatment you're getting, fire your doctor.  Dr. Google might be good to help you understand what the doctor is saying but you're risking your health, using him as a source for diagnostics or advice. 

The bottom line:  If you're not going to follow doctor's orders, why are you wasting money paying him?


by bob53 - 2023-07-22 22:57:48

I appreciate the concern but to clarify, I am not trying to supplant my doctor's advice or go off on my own but rather add to the mix in a coloborative way. This is usually only needed when a specific health issue isnt being addressed by his/her recommendation as is the case with my orthostatic hypotension which Ive been suffering from for the last year.

In my experience the best doctors are the ones who are truly open to working with their patients and open to new ideas when their solutions obviously arent working. Now its true many doctors dont like this approach, and would rather keep throwing pills at your problem until the patient gets tired and goes away. These are the doctors I would run from.





by Lavender - 2023-07-23 11:22:31

I understand. You're being proactive but under doctor's guidance.

To answer your initial question, my numbers pre and post pacemaker have changed. 
I do think you have to figure this differently. That's why I asked my cardiologist about it.

I read this:

A new QTc formula was derived utilizing the constants from the relationship between the spline heart rate QT correction (QTcRBK) before and after pacing; specifically, QTcRBKPACED = QTcRBK × 0.86.

My numbers:

pre pacemaker

QRS 154 in 2019  

         Day before pacemaker 2021 160

QTc  424  in 2019

         Day before pacemaker  459

post pacemaker

QRS  day after pacemaker 136

          March 2021               156

          February  2023          218

QTc  day after pacemaker    524

         February 2023             536

Both numbers were lower at some points between those time frames. Things like dehydration can affect it too. 

Once I discussed this with my cardiologist ( after reading online the danger of high numbers), I realized I was ok and trust my cardiologist to let me know otherwise when the need arises. I am monitored every three months either in his office or by my home communicator device.  Worry would only add more problems. 

My pacemaker restored my ejection fraction to normal 55-60.  Without the device, my heart had already reached its expiration date. I'm not digging too deep. I like understanding what I am experiencing but will leave interpreting to the pro. 



by bob53 - 2023-07-23 13:13:16

Thank you for the comment/info. I'm very happy you're doing so well and found such an improvement with your device.

I read that paper on the .86 factor as well and it is somewhat comforting. I also read that cardiologists will typically subtract 50ms from the QTc for paced individuals. However I also think that having a QTc over 500 in my case may be part of my OH issues and hope getting off my non-cardiac suspect med (Citalopram) will help.

I found that there is a 2011 FDA black box warning on it saying it shouldnt be given to patients over 60 yo in doses higher than 20mg as it can cause OH, arrythmias, long QT and many more symptoms, and shouldnt be used at all in people with these issues. I was on 40 mg for 20 years.

Ideally one of my cardiologists/doctors would have looked at my prescriptions and caught this, but the fact that none of them did only confirms to me the importance of proactive research in our own care.

Self advocacy

by Lavender - 2023-07-23 18:35:27

You said "Ideally one of my cardiologists/doctors would have looked at my prescriptions and caught this, but the fact that none of them did only confirms to me the importance of proactive research in our own care."

Yes, we hope some is watching and checking! We have to be our own advocate as well. I've had a few incidents of being prescribed something wrong for me. 

A physician assistant prescribed me Requip thinking I had restless leg syndrome when I complained of feeling woozy!  Of course it worsened my heart symptoms. I nearly fainted after the first dose while I was stopped at a red light! This same PA prescribed steroids for me (after admitting that I was her first pericarditis patient). It made me worse. 

A gastroenterologist's PA prescribed high dose Zantac for me-300 mg-and my pharmacist advised me not to take it. BUT I listened to the PA because my stomach was in pain. Within days, I ended up with permanent ringing in the ears from the med. 

Just this past year, after switching gastroenterologists-he prescribed something for me that is CLEARLY LISTED ON MY ALLERGY LIST.  Ugh. He also prescribed something that the pharmacist advised me not to take. This time I didn't get the prescription filled and went back and asked my pcp what to do. I ended up with a satisfactory solution. 

Honestly, I believe that the medical professionals are so overwhelmed and are seeing so many people in a day that things can slip through the cracks. Details. 

It is good to respectfully ask and recheck. Research is important but must be run by your expert. I hope you and your medical team find a solution to your OH, Bob. You deserve answers. 


Yes Details.

by bob53 - 2023-07-23 23:03:03

I think you are correct. There is just too much information and too many patients for any doctor to stay on top of it all. Glad you are doing well now.

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