Boston Scientiffic Accolade L331. Settings: DDDR, RYTHMIQ - Off, Lower Rate Limit 40, Max Tracking Rate 135ppm, Paced AV Delay - 80-350ms, PVARP - 250-300ms. VRP - 250-250ms, Minute ventilation and Acceleometer both on.

I'm a 76yo life long amature cyclist, DX'ed with AFib at 65 and Sinus Node Dysunction in May-June '23. S/P PPM Placement in July '23 and successfull cardiac ablation in August '23. My Boston Scientific Tech is a cyclist and knows what I want and need out of my PM. So far, so good. I can reach and sustain Zone 4 exercise and will touch zone 5 periodically (Polar Ignite wrist pulse monitor). I've tried a chest strap and it produces unrelaible data due to, I'm told, PM interference. I've also used the excellent 4th Frontier system - same interference and ECGs are whacked.

 My last in clinic device check on January 25th, '24 shows a 63d PVC count of 166.3K and a 43d count of 60.7k (2640 PVCs/d and 1429/d respectively). Both my cardiologist and EP cardiologist have seen the Device Check Reports and aren't concerned about this. I am.

What I orginally thought was inappropriate pacing at resting HR (a periodic and regular thumping sensation that starts and stops during the day) may be PVCs both chained runs and single beats. These symptoms do not appear under excercise stress at HRs above 90 BPM. The PVCs seem to disappear - the expected occurrance as the QRS interval shortens at higher HRs.  Based on my complaint, my tech at my EP's direction shortened the VRP window from 250 - 300ms to 250 - 250ms on a December 14th '23 in clinic device check. Didn't seem to help reduce PVCs. I don't beleive the EGMS are granualr enough to display the suspect PVC's morphology and a recent 12-lead surface ECG didn't catch a run of them so, docs aren't worried. I've read some literature that reports PVCs being induced by a PM. Raising the Lower Rate Limit to 60 bpm cleared the PVCs up in the study arm. What is the group's take on my PVC count at the last in clinic device check and my PPM settings in general.   


PVCs ( Premature Ventricular Contractions)

by Selwyn - 2024-01-29 20:28:58

Can I suggest you get the definitve idea from:


2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death
A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society
Sana M. Al-Khatib,  William G. Stevenson,  Michael J. Ackerman, William J. Bryant,  David J. Callans,  Anne B. Curtis,  Barbara J. Deal, Timm Dickfeld,  Michael E. Field,  Gregg C. Fonarow,

Whilst you are not having a huge number of PVCs, the guidelines and the concern are expressed in the above reference.

I tried fiddling with the blanking to help my cardiac output during exercie. - it was not successful. Your blanking seems reasonable ( I hope, as I have the same setting). The lower rate limit was raised so that I don't get postural dizziness and also it helps with sudden onset of exercise before the short reaction time kicks in. 40 seems too low - good luck with that.

Would you have medication for your PVCs? What are you trying to achieve at the age of 76 with regard to exercise and personal fitness?  The title of the guidelines tells all and is clearly relevant to your health problems.


by jbuch002 - 2024-01-29 22:16:17

Thanks for your comment and link, Selwyn. If my math is correct, my heart is throwing PVCs at a rate of about 3% of a days total heart beats (around 100K/24h). AHC guidlines specifying interventions start at > 15%. I'm well short of that. This is probably why my docs aren't concerned about it for now. I take no antiarrythmic drugs and don't want to. My LRL was originally set at 60bpm and reduced to 40bpm when I complained that I thought I was getting paced at resting HR (my resting HR is in the low 50s). I'd like to try returning my LRL to 60 bpm and I'll ask for that.

I'm getting a pulmonary function test with the current settings conducted on a stationary bike tomorrow. For my age and level of conditioing I should produce a VO2 Max of 24.4 (50th percentile) to 39.7 (95th Percentile). At age 30 and running 10k races in under 5:30/mile or finish times under 33:00, I got V02 max values of 46.4. If I have retained decent Cardiac Output or CO, good LV funtion by ejection fraction (EF) - my goals, I'd like to see a V02 Max closer to the upper limit value. That would indicate the PM is working fine. I'll post the results tomorrow in this space.

I stopped cycling outdoors about 5y ago - its just too dangerous in S. FL where I live. I now ride indoors at spin studios. Some of the spin bikes are metered and I can compare my performance to others. Some aren't metered. I wear a Polar watch to measure HR optically (not ideal) and I just look around and try to judge if I'm working hard enough and improving rides. I can see my performance in terms of pulse rate and training zones achieved using my Polar watch.

A well known problem

by Gemita - 2024-01-30 07:56:23

Jbuch, thank you for your post.  Many of us are troubled by PVCs and PACs, including myself.  Whilst they are not dangerous in themselves, particularly if they are not frequent or prolonged, they can still cause difficult symptoms and trigger other arrhythmias like Atrial Fibrillation in the case of PACs and Non Sustained Ventricular Tachycardia in the case of PVCs, so they may need controlling.  

Although our pacemakers have algorithms that may be activated to help suppress rhythm disturbances like ectopic beats, algorithms currently available in most modern pacemakers are not able to stop rhythm disturbances like ectopic beats.

I have a Medtronic dual chamber pacemaker.  I have Atrial Preference Pacing turned on and they have set my base rate at 70 bpm which effectively overdrive paces the slower, pausing ectopic beats and most of the time this is very effective, but I have been a good responder to pacing due to bradycardia induced arrhythmia. 

Pausing, slowing, irregular heart beats eventually triggered Atrial Fibrillation with a rapid ventricular response rate.  This was treated with a pacemaker and high dose anti arhythmic/beta blockers initially.  Now my pacemaker and a low dose beta blocker is all that I require.  I was initially considering an AV Node ablation.

Since you have or had AF, I suspect you have always had ectopics.  I would ask about the Rate Smoothing algorithm which I think the Boston Scientific has?   This might help with the short-long-short (SLS) sequences commonly seen with premature ventricular complexes (PVCs). The "short" interval between a normal beat and a PVC is followed by a "long" interval before the next normal beat. A SLS sequence occurs if a second PVC occurs after this "long" interval. Such events could trigger other more significant arrhythmias like non sustained VT.  I get this often from PACs (premature atrial complexes) especially when they come in fast they can trigger Atrial Fibrillation.

Although pacemakers can cause some unexpected abnormal rhythm disturbances, a PVC too can also throw out the timing of a pacemaker.  Many members are currently in discussion with their doctors about this so you are clearly not alone.  My take on what you have told me?  The PVC count may be higher than what is recorded, what is stored, since a pacemaker has limited space and our doctors will not be routinely recording our PVCs on our internal electrograms.  I have learned that the recorded percentages on many of my histograms of arrhythmia episodes are not complete.  In other words, many episodes of an arrhythmia are not recorded because they do not meet the criteria set up by my EP for their recording and storage.  For example my AT/AF burden only includes events that reach the detect rate.  Slower events in either the atrium or ventricle that were below the detect rate for event storage would not be stored.  You need long term external Holter monitoring to give a more accurate picture.

Good luck tomorrow

After my Complex Pulmonary Function Test to evaluate PVCs, inappropriate pacing.

by jbuch002 - 2024-01-30 16:42:33

Thanks for your comment Gemita. I’m commenting after the completion of my scheduled Complex Pulmonary Function Test (CPX). I’ll describe the results later.

Aside from the potential problem with uncounted PVCs, I feel confident, after the CPX, that my PVC count (around 3% of all beats) does not require further intervention nor changes in PPM settings. As I noted in my original post, I had a 10-year history of Paroxysmal Atrial Fibrillation (Afib) and a 40y history of intermittent PVCs (never pathologic in count) and 2nd degree Wenckebach block. In June of ’23, I had a successful cardiac ablation. I had a Boston Scientific PM implanted in July, ‘23.

My pacemaker reports have consistently shown no Afib burden after the ablation procedure. It has been 7 months and there have been zero Afib events recorded on my pacemaker, no heart blocks. Accordingly, I believe that over the last 7 months after PM placement and PM adjustments I may have had some cardiac tissue remodeling which could be responsible for some restoration of sinus node function and improvement in my cardiac conduction system, including beyond the SA node, the AV node, bundle of HIS, bundle branches, and Purkinje fibers.

I have a history of both Sinus Node Dysfunction (SND) confirmed by an extended, 2w Holter. That revealed repeated sinus pauses producing HR below 30 bpm). Separately, Holter revealed 2:1, intermittent 3:1, conduction block with that occurring in the left bundle branch (LBB). Those findings prompted PPM placement.

It now appears my conduction system is pretty much intact. I’m making that assessment based on the CPX I had today where, for about 20 minutes, exercising, on a stationary bike I sustained 4 minutes in a anerobic state. Heart rate peaked at 136 BPM (94% 0f predicted). ALL HEART BEATS WERE INTRINSIC/PHYSIOLOGIC! The pacemaker did not fire until a short burst of a couple of seconds during recovery. There were NO ARYTHMIAS seen on the surface ECG.

My VO2 Max was 31.5 (75th percentile for age, 131% of predicted). My cardiologist who was running the test was impressed with both my fitness level and appearance that during exercise the PM didn’t fire. We both know that, in many cases, conduction blocks and cardiac pauses come and go. Therefore, pacing may be required.  That is exactly what a PM is supposed to do (facilitate physiologic heart beats, pace when necessary).

In addressing my concerns (inappropriate pacing, PVCs), my docs (my EP and cardiologist coordinating care) could have evaluated them several different ways. My cardiologist chose a Complex Pulmonary Function Test (CPX), a rather unique choice, IMO - eschewing a more commonly used Exercise Stress Test (EST) and/or Stress – Echo. The benefit of the CPX is that it delivers an objective, functional endpoint outcome. It answers the most pressing question:  Is the patient’s PPM delivering cardiac function that matches the patient’s functional needs? The CPX proved it, indeed, is doing just that. In my case cycling is an important part of my life and having initially lost that part, having it restored with a successful cardiac ablation and PPM placement. Is a huge deal.

A final comment: After the early morning CPX, I had time to make it to my usually attended 9:15am spin class. My heart flawlessly accelerated to 125 bpm comfortably and then to short bursts of 137 bpm. I felt a few PM beats and maybe a PVC or two. They didn’t concern me as they have in the past, making me anxious and hesitant to push. I pushed, knowing that my heart was doing its job aided by a solidly functioning PM. Life is good!

My goodness

by piglet22 - 2024-01-31 05:33:11


That's quite a write up.

I wish I had 10% of your information about my own condition.

I'll add my twopennuth.

PVCs can be significant.

Without going over PM timing problems and how PMs do or don't cope with them, they can affect palpable resting BPM, they can lower BP, and you can either fall over or blackout.

I can only boast 1000 average PVCs per hour, but if they bunch together they can cause trouble.

Raising base rate from 60 to 70 did nothing to improve things and only Bisoprolol 10 mg daily has suppressed the worst effects, though now I struggle with exercise and a stubbornly unresponsive heart rate.

Yes, I used to cycle a lot but gave up when it got too dangerous.

18 months ago I could tackle steep hills on the bike, but now can't even walk the same hills without stopping to catch breath or let the legs recover.

You can't win sometimes.

MY Goodness

by Selwyn - 2024-01-31 14:30:04

Hello Piglett22,

Why not sack the betablocker? I did. I was not able to swim 3/4 of a length of the swimmingn pool on bisoprolol.

At present I am in atrial flutter. If it doesn't settle in the next week or two I will ask for a chemical cardioversion. Amiodarone is used. Amiodarone is also used for troublesome PVCs. All needs discussion with a doctor before any change.

PVCs are assoicated with a low potasssium serum level. Your diuretic may cause this. That needs to be monitored..

Sorry to hear that your exercise has gone 'downhill' as it were. Best wishes.



Piglet22 said .......

by jbuch002 - 2024-01-31 17:52:20

......."I wish I had 10% of your information about my own condition.".

I'm a Physician Assistant (PA). My 22 years of practice were in ER and Adult Medicine. I retired in 2017. All this stuff is in my wheelhouse, and I am a life-long voracious reader of applicable cardio - medical literature given my history.

Since my CPX that I posted about above, the most important information gained from it being:

The HR during the entire test was physiologic/intrinsic. One short run of pacing during recovery. I’m reassured the PM, as it is intended to do, facilitates intrinsic HR and paces only when necessary. That increases battery life and encourages cardiac tissue remodeling.

 I actually may have experienced cardiac tissue remodeling since the placement of my PPM and subsequent Cardiac Ablation and elimination of AFib. There’s noticeable and detectable improvement in the electrical cycle of my heart. An efficient electrical cycle is key in optimizing ejection fraction (EF) and cardiac output (CO).

My VO2 Max, an excellent subjective measurement of cardiopulmonary wellness and functional cardiac output, is in the 75th percentile for age (76). I’m positive that If I had done one of these tests 2y ago and before elimination of A-Fib and PPM placement, I would not have obtained results like this.

With those objective based lessons learned from the CPX, I’ve cycled in (I spin in indoor studios these days) three separate one hour spinning classes. In all of them I easily achieved 95% of max predicted HR (220-minus my age or 144 bpm), could sustain it for 1-2minutes and otherwise was able to cycle with HR in the 120-125 range for as long as I wanted. I wear a Polar Ignite watch with an optical HR sensor to monitor HR and training zones (not ideal but the PM interferes with the Blue-Tooth signal of a chest strap).   

The important point is that the insight and reassurance the CPX provided changed my mental approach to each spinning class. I did feel some intermittent pacing (very little) and probably a PVC or two. But my thinking was the PM was doing what it was supposed to do with an intrinsic pulse, and effective cardiac electrical cycle most of the time (maximum cardiac output assured). Previously, when I felt these perturbations in my pulse, I was resigned to thinking something was wrong with the PPM or my heart, I better slow down. I lost the mental motivation to push the cardio-load. I also complained to my EP Cardiologist and my Cardiologist who both took my complaints seriously and scheduled the necessary follow ups with Boston Scientific reps and testing (the CPX). I now think the PPM settings I have are fine and tested with objective measures to prove they are. I wish the best result for all of you that have commented on my original post. Thanks for your input.

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Hi, I am 47 and have had a pacemaker for 7 months and I’m doing great with it.