AF or Sick Sinus Syndrome

I've been suffering from episodes of rapid heart rates in the region of 140 and low rates of as low as 25 for about 6 years, these being measured at home using my BP machine and Fingertip Pulse Oximeter Heart Rate Monitor. The low rates seem to have been getting steadily worse together with episodes of missed beats and pauses in line with the increase in Beta Blockers and more recently Calcium Channel Blockers to the extent that I had to stop taking the Diltiazem recently. I also suffer with lightheadedness, breathlessness and occasionally feel like I am about to blackout and have to grab hold of something. Whilst walking briskly on my treadmill I have noticed my pulse drops from around 100 to low 40 and I suffer lightheadedness and extreme dizziness to the point I have to stop and hang on to the machine in the fear of collapsing. I have read that this could be Sick Sinus Syndrome (SSS) and wonder if anyone has experienced similar. When I mentioned my thoughts with regards to the Beta and Calcium Channel Blockers to my Arrhythmia Nurse during a recent telephone call he said the drugs could not be a cause, yet there seems to be plenty of evidence to suggest a very definitive link to SSS and Beta / Calcium Channel Blockers.

16 Replies

  • I have been diagnosed with sick sinus syndrome and vascilated between fast AF and bradycardia - I got bad sinus pauses that made me pre syncope as you describe especially when converting back to NSR from AF after runs of tachycardia and exercise induced - although when first diagnosed as just AF once it was understood I stopped beta blockers completely - I had a couple of ablations that have stopped the fast AF and to date not had the sinus pauses - although still bradycardic suspect chronotropic incompetence (stress test next week) - I would ask the expert - your EP as all the symptoms you describe I experienced - take care especially if you are apparently exercising to the point you might pass out - you need monitoring and tests before you carry on pushing yourself Jo

  • Thanks very much for your reply, my concerns relate to having been on Beta Blockers for 12 years for nothing more than high BP which seams to have antagonised the rapid heart rate, this then being diagnosed as AF without any real meaningful tests and because of worsening episodes more aggressive Calcium Channel Blockers introduced to the point where I was suffering high heart rates most of the time, these coincidentally having reduced by probably 75% since I stopped taking them. Still suffer with the sinus pauses though, hence my question regarding SSS.

    Thanks again, a sufferers first hand experience is invaluable.

  • You do need proper tests and a review of your treatment don't you? As a matter of some urgency if you are nearly passing out - frustrating if you suspect your drugs have caused the problem but you have to deal with your current situation and it doesn't sound safe to carry on as you are without changes - push for a better diagnosis and treatment Jo

  • When I was first diagnosed with AFib I was put on beta blocker. I was on the drug for about a year and my HR went down into the 30's. I was feeling awful, tired, weak and dizzy. My EP suspected I also was suffering sick sinus. He took me off the beta blocker and put me on Flecanaide and have been on it for almost ten years. My HR now is between 50-60 and I feel better. My advice would be to have your EP change your meds before you black out or worse . Keep us posted on how you are getting on.

  • Thank you very much for your thoughts and experience, I have a lot to discuss if and when I next see my consultant.

    Thanks to all who take time out to read any reply, your experiences are invaluable..

  • "Sick sinus syndrome" describes intermittent slow heard rate (bradycardia) and fast heart rate (tachycardia) and can be called "brady-tachy syndrome". The tachycardia part is often AF (but not always). This overlaps with "vagal-induced AF". The vagal nerve slows the sinus node (natural pacemaker) and it is difficult to be sure whether the slow heart rate is mainly due to over-active vagus nerve or a defective sinus node (SN disease) – it's often a combination of the two.

    Either way bradycardia is a powerful trigger for AF, and drugs which slow the normal (sinus) rhythm may well make the problem worse – especially beta blockers (e.g.bisoprolol), calcium blockers like diltiazem and even amiodarone / dronederone. There is one heart stabilising drug, flecainide, which does not slow the sinus node and this is why it is so valuable. Another similar older drug, disopyramide actually (partially) blocks the vagus nerve as well and so should be ideal – but blocking the nerve can cause troublsome (non-dangerous) side-effects and makes the AF go faster if it does break through so it has largely "gone out of fashion"*

    If the bradycardia is severe the best treatment is implantation of a pacemaker and this may prevent the AF as well. If not, the anti-AF drugs can be added safely and with much greater success.

    AF ablation does not help the bradycardia except by removing the need for beta blockers etc.

    *It's important to understand that drugs can go out of favour not just because they don't work but often because their patent runs out so nobody can make a big profit selling them. Also newer drugs may be more effective ON AVERAGE but for some individuals the older drugs work better or have less side-effects. One of the best antiarrhythmic drugs ever, ajmaline / prajmaline never got widespread use because the company that owned it were useless at marketing.

  • Again, thank so very much for your reply which both further confirms my understanding better, has provided even more invaluable insight to this complex disorder. I do find it increasingly frustrating when I am told by "the professionals" other than what I physically experience on a day to day basis, it's my body and my symptoms which I am aware can be entirely different with each individual, we shouldn't all be tarred with the same brush.

    Thank so very much.

  • 'AF ablation does not help the bradycardia except by removing the need for beta blockers etc.'

    I understand this but in my experience without the episodes of fast AF and tachycardia since my ablation mid September (ie 5 months ago) I have not experienced the extreme rebound low 30s rates and sinus pauses that caused me scary pre syncope. I also used to frequently have a rate below 40 and sometimes low 30s in the morning that made me queasy and likely to go into arrhythmias.

    I am still Bradycardic (~45-50) though but off all drugs (only 52) and hopefully postponed having a pacemaker for a while longer. I was on the anti-arrhythmic Propafenone not Flecainide before.

    I found this article early in my diagnosis which gave me food for thought on treatment. I realise it might not be everyone's choice but it is important for the patient to be able to consider all their options and if I can achieve a drug free and hardware free period then it was something I personally wanted to try for. I have no doubt I will need a pacemaker at some stage but it is an area that is undergoing a lot of development at the moment and it might well be possible to have leadless ones in the next few years.

    I like reading your posts as a rounded professional rather than some of the very subjective views and opinions dressed up as facts I see so please keep up the good work. As a single patient with only my own experience to go on I will only ever relay that as information for others to add to their own experience. I have found the sharing of people's very personal experience very helpful to me in understanding my issues (big thanks to Buffafly and Sheppey who introduced the correct terminology Chronotropic Incompetence to how I was feeling - I am undertaking a stress test week to see what my heart is doing when I put demand on it).

    Thanks again.


  • Dear Jo, So pleased to read that since your ablation-you have not had very low bradycardia (30bpm) -and that your Sinus Pauses have also stopped? Long may this continue?

    In 2014 ,I was experiencing all the symptoms... then suddenly ,for no reason, they all ceased for a few weeks. I was not having any medication. I was receiving no treatment. But I did have an implanted loop recorder ,assessing and recording everything. I felt very well once again. But, unfortunately, the SA node decided to, once again, work when it felt like working? Back with a vengeance!

    The Pacemaker was my only option.

  • That's very interesting and you're quite right – I forgot to mention the rebound effect which is important. I have ammended my earlier posting to include this.

    It's true that most people with sinus bradycardia can manage without a pacemaker for years, but my experience is that when they eventually do have one implanted they report more energy, improved circulation, better sleeping and even mental alertness. Typically thay say something like "I feel so much better – I wish I'd had this done years ago" or sometimes "Why didn't you suggest this sooner?" which is funny because usually I DID suggest it earlier!

    Of course this is not proper evidence but it does encourage me to offer the pacemaker option even when the symptoms are quite mild.

  • Thanks again, I wish I was able to get to to converse with my consultant as easy, twice in three years and then only to listen to his opinion AF = Ablation and that's it - done. I will certainly be pushing for confirmation of my condition and a pacemaker if appropriate. Fingers crossed.. I might be able to get my life back.

  • I also suffered from Sick Sinus Syndrome, Sinus Pauses, Tachy/Brady Syndrome and Chronotropic Incompetence. I could only take a maximum of 1.25mg Beta Blocker-to try to stop fast AF (up to 289 bpm). Anything above the 1.25mg would make the Bradycardia worse (down to30bpm). My only option was a Pacemaker to keep my HR up to 60bpm. Once this was implanted ,I have been able to receive higher doses of Rate and Rhythm medication. I have still had long runs of fast AF and AF.... now eased with the medication. I have been offered Cryoballoon Ablation .

    From my personal experience, I know Beta Blockers will cause severe bradycardia.

    Everyone is different. I would confirm that if you require treatment for any electrical problems see a EP... For all plumbing- see a Cardiologist.

  • Hi sheppey, thanks for your reply, you and other seem to confirm my thoughts, I'm suffering SSS and the Beta and Calcium Channel Blockers just aggravate the problem albeit my Arrhythmia Nurse insists this cannot be the case, without any real evidence I might add. What I mean by this is I've told him on many occasions recently since changing to the Adizem my symptoms are worse. Nevertheless, I have an appointment for the fitting of a 48-hours monitor, lets hope it confirms what I feel and I can get something done along the lines you describe.

    Thanks again.

  • Dear Cypbill, I know how difficult it is to correctly diagnose Sick Sinus Syndrome. I was very fortunate that every Doctor ,Consultant and Cardiologist recognised immediately what I was suffering from. Because it is an umbrella term- for a given set of signs and symptoms-that are unique to the individual? Recognising and treating it are different issues? In my case ,it was experimenting with medication to ease the symptoms....But this failed as everything I tried made the symptoms worse. It took a very long time and eventually ,the medication could not control my fast AF. I took a long hot shower to bring me back to a HR of under 110 bpm.... Enough for a pacemaker to be implanted. We only know our own body. We need to learn everything possible to better understand it. We need to look after it.

    We need to question and seek answers.

    I believe a little knowledge can be dangerous!

    Always seek help and advice and good information from those qualified to give it.

    An EP for Electrics . a Cardiologist for Plumbing!

  • When I began to have Sinus pauses my cardiologist told me they were caused by Diltiazem. He reduced my dose from 240mg to 120mg but said this was not a long-term solution so I needed an ablation for AF and Afl or a pacemaker.

    I was surprised but he said I had signs of tachybrady syndrome and the Diltiazem was definitely making it worse.

  • I think that you need to get an appointment with your EP booked up and keep pushing.

    Secondly you need to keep an accurate log of events (date and time) but keep it in bullet point format. You are probably doing this anyway.

    Thirdly if you have AF and other arithmyia(s) then finger pulse oximeters are nearly always useless for HB (they can easily be 100% or more out - classified as a chocolate fire guard) and even for SpO2 levels they can be inaccurate**. Unfortunately they are NOT consistently accurate in that one day their reading could be LOW and the next day HIGH. An electronic device such as the AliveCor is the most accurate and importantly records the ECG which can be viewed by your EP. Best to set for 2 minute readings.

    For BP you should buy a proper cuff monitor that is suitable for AF and approved by British Hypertension Society and NICE (Microlife BPWatch Home is one but get the A model which denotes AFib). This also shows HB but sometimes the reading is within +or- 2 or 3 HB and others much wider. I will do a comparison of my results sometime (I have both) but I suspect that the closeness is only around 25%. However when I compared with a wrist monitor over a year ago wrist monitor was inaccurate about 90% of the time.

    If I were in your shoes no way would I be pushing anywhere near the point of feeling feint or collapsing because that is so risky not just for heart but also potential falls.

    ** Many GPs do not know oximeters are inaccurate for AF and arithmyia sufferers. Also my Sleep Apnoea consultant said about the SpO2 level inaccuracies and interestingly GP and Cardiac Arithmyia nurse were unaware of this.

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