When Your Heart Is Normal but It Still Pounds

"I had the ECG, I had the echo, all normal. And every night it pounds."

People say this. And they usually add one line. "Am I just being sensitive?"

I tell them no. And then I explain why the tests came back clean.

The heart beats on its own

This part has to come first.

The heart has a place that makes its own beat. The sinoatrial node. Take it out of the body and set it on a dish and it beats for a while by itself. It doesn't beat because a nerve tells it to.

So what do the autonomic nerves do? They hold its speed.

The vagus nerve applies a brake. While that brake is on, the heart runs slower than its own tempo. Tense up and the brake lets go and the accelerator goes down.

Here is an interesting number. Left alone, the sinoatrial node beats about 100 times a minute. Our pulse is around 70. That difference is the brake. Every waking moment, the vagus nerve is holding the heart back.

What tests see and what they don't

The ECG looks at whether the electrical signal is going round properly. The echo looks at whether the valves and muscle are sound.

Both look at the heart as an organ. But pounding is a story about the hand holding it. The organ is fine; the hand holding it is unsteady. (What "your tests are normal" actually means)

So "normal tests and a pounding heart" is not a contradiction. They are looking at different things.

And there is one more thing

At the same pulse, some people feel it and some don't.

There is a separate sense for noticing the heart beating. When that sense is heightened, the beat feels large even when the pulse isn't especially fast. So a 24-hour monitor comes back with unremarkable numbers while the person spent the night feeling it.

Both are true. The numbers are right, and what you felt is right.

The face it comes in

• Worse when tense or tired, and especially when you lie down at night
• Pounding along with cold hands and feet
• Shallow sleep, waking often

There is a reason for the night. Lying down, the noise around you drops and the sounds inside come up loud. And night is when the brake should be on deepest — and for some people it doesn't set.

I look at the brake, not the heart

I don't try to calm the heart. The heart is fine.

I look at why the brake won't set. Sleep, or years of tension, or digestion. Mend that and the brake comes back on its own. (Not being able to sleep and not being able to fall asleep are different)

That said, if you haven't had your heart checked, that comes first. The order matters.

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If you've been told you're just being sensitive, you can set that aside.

This is a story about the hand holding the heart, not the heart — and that hand regains its grip.

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References

• At rest the vagus nerve holds the heart back, and that restraint amounts to roughly 30 beats per minute — The Journal of Physiology, 2014
• Among people fitted with a 24-hour ECG for palpitations, about 84% of recordings came back normal — Annals of Noninvasive Electrocardiology, 2008
• What an ECG records is the electrical activity of the heart — Asan Medical Center

Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)