Flecainide and Diltiazem

I've been taking Flecainide for almost 5 years now, 50mg twice daily, and it's kept me in NSR perfectly the whole time. My new EP wants me to consider adding Diltiazem to this now, due to the potential "rare" side effect of my heart going into a 1:1 conduction rate, which is a very bad thing to happen. Diltiazem brings this risk down substantially.
Are most on this forum that are taking Flecainide also taking either Diltiazem or Metrpolol to offset this risk? My new EP acknowledges my risk is low because 1) I'm on low dose 2) no issues with Flec for almost 5 years now.
Thoughts anyone?

Yeah, most EPs who prescribe flecainide will prescribe a rate control drug to go with it. The 1:1 conduction issue is very rare, but it's also potentially lethal, so I think it would be foolish not to take the precaution.

...I understand, and yet, I cannot find even 1 case study where someone actually died from the 1:1 conduction as a result of taking Flecainide? I know there are cases of the 1:1 happening, and it's certainly a tough situation to say the least, emergency room etc. But not even 1 actual death listed anywhere? Taking Diltiazem has some risks in itself, and can certainly affect our standard of living. I just want to make sure I'm not piling pills onto pills for the wrong reasons. I also wonder why my previous EP did not think I needed a nodal blocker with my low dose of Flec?

I was made aware of the potential 1.1 crisis that can occur when I first started taking them.

I've taken 50 mg flecainide with 12.5 metoporol for several years, first regularly to control my afib and post ablation occasionally for annoying pacs. (I'm extremely symptomatic, a walking EKG.)

At one point, they attempted to switch me to diliazem, I don't even remember why. First doze I broke out in a red rash on my cheeks, stopped it and went back to metoporol.

Sandy

Not being able to find case studies doesn't mean much. If you search google scholar for terms like "flecainide atrial conduction tachycardia" (without quotes) you'll find numerous articles describing the problem. Most of them are old articles, dating to when flecainide was a new drug, but they're still relevant. It's a real threat and it really happens, just not very often. It's dangerous enough that I wouldn't avoid a drug with minor side effects like beta blockers or diltiazem just because the odds were very low. It's a pretty rare EP who prescribes flecainide without a rate control drug.

I’m a case study of one on this forum with getting v-tach while on Flecainide. ICU said I was lucky I didn’t die. You can even get 1:1 even while taking a BB. Flecainide is a black label drug.

Each and every time I left my cardiologist’s exam room after a biannual visit, my doctor would start to turn the doorknob to exit, he would stopped and turned around and say Flecainide will kill me.

The drug does work well but it comes with a rare mortality risk for some. I was so desperate to be in NSR that I ignored the risks thinking it wouldn’t happen to me.

I have been on Flecainide for over 45 years off (probably a record of someone being on a drug like this for so long) and on mostly on since diagnosed at 30 with AFI B - now 75. ( I have had two ablations over the years) Tried many a BB did not do well. Could it kill me? Maybe.

My heart rate is generally in the 60's. At this stage of my life, I am not concerned about this rare occurrence. Neither have the many EP's or Cardiologists seem to be concerned that I am not on a rate drug. I am likely an outlier.

Also, my spouse is on Flecainide recently for flutter, his heart rate is in the 50's even with the flutter, so no BB for him. In fact, he is very limited on any rate control drug due to having an athlete's heart. (he will be having a conversion soon)

Every case is different.

Very interesting... yes my previous EP, who gave me my last ablation, and who eventually put me on the Flec never even mentioned a BB. My resting heart rate is 60bpm now, and my afib is vagal, and I've been on the lowest dosage of Flec alone successfully for almost 5 years now... all lowering my chances of the 1:1. My current EP said he "understood the philosophy and did not disagree" with my decision not to take the Diltiazem, but he just wanted me to understand that the 1:1 is very serious, although unlikely to happen. I appreciate that from him.

I understand Casey, and appreciate your thoughts and do not disagree with you at all! It's a tough decision, and I'm not 100% sure I won't start taking it.

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Sdweller
My resting heart rate is 60bpm now, and my afib is vagal,

How does one determine that their afib is vagal?

"Vagal AF" and "adrenergic AF" refer to two different types of atrial fibrillation (AFib) primarily triggered by the dominance of either the parasympathetic nervous system (vagal) or the sympathetic nervous system (adrenergic) respectively, meaning that AFib episodes in a "vagal AF" patient are more likely to occur during rest or after eating, while "adrenergic AF" episodes are often linked to stress or physical exertion.

Thank you for the reply Sdweller.

Perhaps I also fall into the Vagal AF category. At night while asleep. They have said I have Bradycardia also, although my number of "low heart rate" notifications, below 40, have pretty much stopped. Could it be better because I stopped drinking wine which perhaps slowed my heart rate further, still at night I'm high 40's mid 50's. Have a little bit of artery plaque but otherwise all my cholesterol numbers are great and recently an increased Left Atrium during an echocardiogram but they did not include the measurements in the report. Trying to read everything I can before my next EP appointment whom I have not seen in a little over 2 years although I have seen the regular cardiologist and my PCP.

Those traits are mine also... borderline bradycardia at night, andmost afib happens at night in bed. Large meals also can trigger afib for me, as the vagus nerve is active in digestion. BTW red wine of all alcohols are known trigger for afib, as the preservatives in them can cause arrhythmias. It was not easy, but I stopped my red wine consumption long ago. (OK...MAYBE 1 glass on a special occasion as early as possible!)

I have paroxysmal AFIB since that started in 2012. I've never had an ablation. I've been taking 100MG of Flecainide and 60MG of Diltiazem 2 times a day since Jan 20 2021. I haven't had an AFIB episode since then.

Mt Garmin swim watch tells me that when I was doing my 1 mile swim in the pool 3 times a week in 2018-2020, I used to be able to get my heart up to an average of 140 BPM. But that was prior to my 6 week covid bout that started in Nov or 2020. Now after 4 years of the medication, my average heart rate since restarting my swim 4 months ago is only 94 BPM and I've been consistently fatigued during the day and take 2-3 hour naps after lunch. Is the medication causing this and what can I do to alleviate my fatigue? I ran it by my cardiologist and he said to address my sleep apnea first before considering adjusting my dosage.

Anyone else having this issue?

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joeponcakia
Is the medication causing this and what can I do to alleviate my fatigue?

It very likely is the meds, particularly the diltiazem because its entire purpose is to lower your heart rate. It or a beta blocker are often prescribed with flecainide to protect against a rare but dangerous side effect known as 1:1 conduction. I don't know of anything you can about it other than changing the meds or dosages.

But I will say that your doc is right in saying the sleep apnea needs to be a priority. Sleep apnea is a huge contributor to afib.

Undiagnosed OSA was my problem, and it culminated in a diagnosis of paroxysmal AF, which you have. My very last diagnostic as a polysomnography, and that's where my cardiologist and I learned what had apparently caused my recent development of AF. I had to get my OSA treated first, and only when my heart began to slide quickly toward persistent AF did my cardiologist refer me to an EP. Two ablations later, I am now 24 months free of AF.