Sudden drop in heart rate

[Jerry_NJ]

For those who don't already know me, I suffer from permanent AFib and take a 50mg BB and a 240mg CCB to control/lower my (ventricle) HR.  That said I have found it typical to have a morning resting HR in the lower 70s, usually measured over a full one minute period to avoid short period low runs do to missed/delayed HBs.  My low activity HR ran in the 85-95 bpm range.

This morning I found my HR to be about 62, so I decided to put on my HR monitor.  The disadvantage of this device is the sample period is rather low, perhaps 10 second.  In any case, the device confirms the lower HR.. and shows counts in the 58-65 range when seated  and in the low 70s when up and walking around the house.  I also notice a slight tendency to slip into a light-headed feeling when I stand, that passes and I can walk outside on the level without any fainting or worse reactions.  I think the lower HR is the cause, and I may adjust, but I still wonder why the HR has suddenly dropped at least 10-15 bpm when at rest, and perhaps 20 bpm when under light physical load such as walking.

I did start taking a fish oil omega 3 supplement about three weeks ago.  I take 300 mg three times a day, with meals.  The BB and CCB are both slow release.  I take the BB in the morning and the CCB before bed time - about 11PM.

[is_something_wrong]

Hello.

During AF the upper chambers do not contract (during flutter they contract to some degree). You can not hear or sense the fibrillation.

It would possibly be an idea to buy an 1 lead EKG to print some results now and then? You seem qualified enough in arrhythmias to interpret this.

Please be aware that your heart rate can change with vagal or sympathic stimulation even if you are in permanent AF. It is completely normal to have changes in your heart rate, depending on mental state, eating, coffee, etc.

By the way, thank you so much for the detailed explaination of the US health insurance system. I will answer it, but I am afraid I have been a little short of time lately.

[Jerry_NJ]

I'll bring this back up as my situation has changed, or returned.  

As mentioned I was unsure of the cause in the lowering of my HR because I was messing around with Propafenone... I have stopped that on good advice and had seen my HR returning to the usual 70s when really at rest and in the 100 range when up and walking around.

Today it dropped back down, and right now is reading in the upper half of the 50 to low 60s and has done so all day. Up and walking around it does come up, but slowly.. going up to the 70s when walking around - with a little light headed feeling.   AT the pharmacy a couple of hours ago my BP was good, just below the numbers for no problem, and my pulse come in at 70, I had just walked in and sat there for no more than a minute to get the reading so I think the HR was heading toward the 60s or less.

I wonder short of an EKG if it is possible to "hear" AFib, I mean besides the irregular ventricle rate.  When I listen I hear good solid HB with some pauses, but nothing over 1.5 seconds I'd estimate.  I wonder is my atrium is actually pumping by going in and out of fibrillation.  

[is_something_wrong]

Just some thoughts:

I don't think antiarrhythmic drugs (except CCBs and BBs) are used when it's accepted that NSR is impossible - they don't slow ventricular response as much as the CCBs and BBs, and risk of side effects (ventricular arrhythmias) are much higher. However, antiarrhythmic drugs (propafenone, flecainide (that are actually quite similar) sotalol (bb and potassium blocker) and amiodarone) are as far as I know the only drugs having a possibility converting the A-fib. BBs don't - they can prevent it if it's adrenaline induced, and Verapamil (as I assume you use, due to the 240 mg dosage) can convert certain supraventricular tachycardias but rarely A-fib, is great reducing ventricular response, but doesn't stop the fibrillation.

Sodium blockers (propafenone, flecainide) can reduce both heart contractility and heart rate, hence potassium blockers are more common in the setting of heart failure. If you do this little experiment by adding sodium blockers to your medications (which I think is a bad idea if it's not cleared by a doctor, due to the side effects and the lack of effect if you can't be converted to NSR), it's not surprising you get both lower heart rate and hypotension.

Low intake of salt reduces blood pressure as you know. A sodium blocker have a similar effect (though this is not the main effect). Remember, you need a slightly higher heart rate in A-fib to compensate for the lacking "assistance" in blood pumping from the atrias.

Best wishes and keep up the good work as our community leader :)

[Jerry_NJ]

Thanks, I have a confession:  In addition to the fish oil I had just a couple of days before the fall in HR (which was accompanied with a slow to respond to physical activity) I decided to experiment.  Not much of an experiment if I didn't "connect the dots", but I have done this experiment before an found no changes... this time, however, I was/am on a CCB.  

When in NSR I took Prophfenone 225 mg tabs three times a day (every 8 hours).  When I was directed to stop taking that medication as I was in AFib I still had a large supply left..which I never disposed of.  Given I had no recognized side-effects from taking 675 mg of this medication each day, I figured I could experiment with low dose levels at almost no risk.

Well I decided (again I say) to try a little to see what it does and I took a half tablet (112.5mg) twice a day.  I think it had been two days when I noticed the drop in HR and (due to age?) didn't take the experiment into account.  I have now stopped the Propafenone and the HR is coming back up to 70s at rest.

I'm not sure how to take this experiment information to my doctor, as he will be very unhappy to learn I am "playing" with prescription drugs.  But it does appear that the propafenone must be reducing the severity of the AFib.  Given the BB and CCB remained unchanged and they collective have primary effect on the ventricle response to HB signals I conclude there is a possibility that the frequency of HB signals was reduced by the propafenone.  I think I will try the experiment again once I have reestablished a base-line HR characteristic.  If I get the same result I will at least put pressure on my cardiologist to again try medications that have some potential to convert the heart to NSR.   As discussed on other posts, my cardiologist has put me on the "treat the symptoms only" regiment and I am no longer a candidate for conversion to NSR.

[cindy707]

I think you may find your answer by logging onto ep.physoc.org and looking up Postural effects on heart rate and blood pressure.  Remember that the resting heartrate falls with age for all of us but especially with men...hope this was helpful.....

[Jerry_NJ]

Thanks, and a more "natural way" to lower HR too... fish oil rather than BB/CCB.  

I have taken fish oil in the past, but I think never in the recommended does of about 1 gram a day... it was recommended by Dr. Rosenfeld (a Fox News medical expert - on during the weekend, Saturday I think).  He is a cardiologist, and while he looks older than me, than I think I look, he seems to still be in medical practice.  

If it is the fish oil it took some time for it to build to a level that I took note of...I'd guess I've been on the fish oil about three weeks.  Right now, sitting and typing my HR monitor reads about 70, jumping around a few points due to AFib.

I'll discuss with my cardiologist on my next (six month regular) visit.

[itdood]

It's the fish oil, I'm pretty sure.  Studies have shown that fish oil lowers heart rate.

Perhaps you could lower the BB or CCB if you intend to stay on the fish oil.