3 things that come in to my mind immediately are: consider magnesium deficiency, get your thyroid checked, and you may be too sensitive to caffeine to drink it at all.

Maybe not the best answer, but sometimes you can just have funny little arrhythmia's that are a physiological problem. Some come on randomly, others have specific triggers. I have had two heart surgeries for an atria-ventricular nodal re-entry tachycardia, and for years mine was a just a random few bursts of arrhythmia, starting at about the age of 3 until I was 17. It usually happened when I was on the couch or resting. When I was 17, it changed- I started getting them every week or so, and a really debilitating can't-breathe-pass-out-emergency-room ones about once a month. But, even when they were happening that frequently, they still didn't show up on any monitors or stress tests. The first time they caught it on a monitor was when it was induced during my first heart surgery. This was after about 20 24-hour monitors and 4 7-day monitors, as well as maybe 12+ trips to emergency, and 24+ trips to clinics. So, needless to say, it is not unusual that you don't see anything on a monitor.

Some typical triggers I was told to look for when they were first investigating (even though they ended up not applying to my tachycardia) was caffeine, exercise, alcohol, blood pressure changes, and lack of sleep. One thing I tried with my cardiologists support, was I had a week-long monitor on and just tried to do every possible trigger during that time I had the monitor on- he called this the "real life stress test", and said it was much more effective at recording irregular rhythms than any one they could perform in the office. I went to live sports events (hello blood pressure rising), went out clubbing (drinking and lack of sleep and physical activity), drank coffee w/booze (two in one!), did sprint-rows on no sleep (tired and vigorous exercise), and just generally had a fun/tiring weekend. My cardiologist said that you won't find a lot of doctors who will tell you to go ahead and do this, but if you can get something on the monitor it could settle things for you in the long run.

My advice would be to talk to your cardiologist again, and see if your doctor might want to monitor what mine called the "real life stress test". If you and/or your doctor are not down, it probably won't change anything to get a second opinion. Just be attentive, track all the occurrences in a calender. If you can notice any common events that happened around the time you got your arrhythmia's (days where you were tired, where you had some wine the night before, etc), that could be helpful if you wish to investigate further. This will also help identify any changes in frequency.

As my cardiologist said to me, so many people have these funny little arrhythmia's, and for the most part they don't mean anything- it's just a little nerve firing, and even though it feels big to us, it can be the heart equivalent of a twitch in your foot. However, if it is disrupting your life (as mine was in a big way), it is a pretty easy fix- usually just one closed heart surgery, where they either freeze or burn the nerve pathway that is causing the disruption.

I'm not sure if yours is the same thing at all, might not even be an electrical problem (though more are, as it's pretty easy to rule out structural after an ultra-sound), but my experience was I was fine living with it, until it became an obstacle. Then, I had two relatively easy heart surgeries, and so far haven't had any other problems.

If I get arrhythmias I do the following and it goes away (alternately, if I don't have them and I do the opposite, they come back):

Stop all calcium intake and take 200mg magnesium glycinate every few hours.
Stop all salt intake and eat a lot of potassium-rich foods like tubers.
Ensure that the zinc:copper ratio hasn't gotten too high.

If you eat industrial garbage food, there are tons and tons of potential triggers. Most of them involve the excitatory amino acids (glutamic and aspartic acid), but there are a lot of preservatives that are triggers for us as well.

It's good for someone to get a cardiac echo if they've never had one just in case, but no cardiologist is ever going to attempt to correct the issue for real. It's all either a shrug or a prescription.

The good news is that everything I have seen has indicated that it's not worth worrying about, especially since it is itself exacerbated by the anxiety.

Green tea and red wine both give me heart palpitations, similar to what you are describing. My brother once tried a concentrated green tea supplement and the same thing happened to him. When he returned them to the health store, the mgr said they had so many returns with the same complaint that they were no longer carrying the product.

Same thing happens to me and has been happening for years. It started in the fifth grade has continued until now (I'm 23). Been to every specialist and everyone is stumped. Happens when my blood pressure changes suddenly (standup or sit down too fast, sudden body position change). Would really love to hear from anyone else who's combated this.

I had a very similar problem, when I felt irregular heart beats when I laid down at night, and then a friend suggested I start supplementing magnesium because it stopped the same problem for him, and I did, and I no longer have any heart palpitations or irregular heart beats. Maybe give it a try?

Do you do any kind of steady state "cardio" exercise for prolonged ( 1/2 hr or greater) sessions?

I experienced arrhythmias for all 35 years that I did jogging/distance running. I thought I was fit because I could run a 42 minute 10k @ 57 YOA. I wasn't. I was training my heart to function in a very narrow range.

Once I quit that "cardio" silliness and went to high intensity weight & interval training the arrhythmia vanished never to return. it's been 8 years.

YMMV

These episodes can be scary. If you're concerned, you can ask your doctor to have you wear a Holter monitor for a day or two -- it will capture what's going on when it happens as usually during the short ECG its rare for it to happen "on cue". We never did figure out what my strange racing heart episodes were several years ago, but at least I was reassured it wasn't anything wrong with my heart. No abnormal rhythms or missed beats or anything. It was a big "phew"!

I have this as well. It appears after I eat certain foods and eventually started happening when I lay down. Annoying as f***.

I eventually came to the theory, after much googling and trying a variety of things, that it was actually a form of heartburn (maybe even a hiatal hernia). The vagus nerve is close enough to the esophagus/hiatus that it can be aggravated by stomach acid and thus trigger the heart to race/pound. Google vagus nerve and pounding heart and whatnot and you'll find people talking about this.

It sounds peculiar, I suppose, to conclude that pounding heart = "heartburn", especially if you don't get heartburn, but the things that trigger the pounding heart are the same that trigger heartburn in others. And, in fact, when the problem was at it's worst I eventually started having burning, acid burps.

Self-medicating as if it was due to an irritated esophagus ("inner fillet" aloe juice, paying attention to my posture while eating, digestive enzymes and HCL to help my system digest food better, etc...I do not recommend the CW approach of using antacids :P) had a profound effect. I've pretty much solved it except for the occasional rare heart pounding with coffee. Even that I can solve within seconds by sitting taller so I don't scrunch my stomach up into my diaphragm.

Did the holter monitor, came back with 20,000 irregular beats per day. Playing the best squash of my life but am worried its like Russian roulette! ECG says I have had an infarct. Nothing showing on CT scan. Low potassium. Reduced coffee to one cup a day.still here, life goes on at 40.

Oddly enough this same thing is now happening to me. Only when I lay down.

I've been strict paleo for over 5 months now and this along with the occasional lightheadedness are the only issues I've had. Outside of those two things I've exceeded my expectations on this diet. The heart thing just started happening in the last couple of weeks. If I was going to check my thyroid what specific test should I target? It seems like a lot of paleo issues tie back to the thyroid. Why is that?

Due to all of the reading I've seen on thyroid function I've recently increased my carb intake (more fruit and higher carb veggies). This has caused the weight to drop more quickly and has also increased my performance in the gym.

A neat trick I learned from a bio major in college: For those random little tachycardias/arrhythmias, giving a few short, strong coughs usually resets the nerve/processes that occasionally misfires and causes them.

I get it whenever i eat fat. When i try to go keto I get it bad... my main macro is starch now and i dont get it at all

I get this occasionally and make myself an electrolyte drink, which helps me immensely. I just mix sea salt with spring water, lemon juice and a dash of honey. I also try to eat potassium-rich foods and will have one can of coconut water that day. The last time this happened was after I moved all weekend (so lots of physical exertion, stress, etc) plus I fell off the paleo bandwagon and had some GF sandwiches and pizza (kitchen out of commission) which pissed off my intestines. My arrythmia was so bad that day I couldn't get out of bed. That was the first time it really impeded me, kinda freaked me out!