When Are Palpitations Concerning?
Why a racing, pounding, or irregular heartbeat can mean very different things
That feeling your heart just did something weird
Patients describe palpitations in all kinds of ways.
“My heart is racing.”
“It feels like it skipped.”
“It’s pounding.”
“It feels irregular.”
“It feels like a fish flopping in my chest.”
And honestly, all of those descriptions are useful. Because palpitations in the ER are not one thing. They are a sensation. Your heart may be beating too fast, too hard, too irregularly, or just differently enough to make you stop and notice it. Sometimes that feeling is harmless. Sometimes it is not.
That is why it gets taken seriously.
What palpitations actually are
Palpitations are your awareness of your heartbeat. Normally, your heart does its job quietly in the background. You are not supposed to feel every beat. When you do, something has changed. That change might be speed, rhythm, or force.
Some people feel a racing heartbeat. Some feel an irregular heartbeat. Some feel a strong pounding beat. Some have palpitations that come and go, especially at night or at rest when everything else is quiet and suddenly your heart decides to become the main character.
This is why heart palpitations causes are so broad. The heart may be reacting to stress, dehydration, blood loss, thyroid problems, anxiety, low oxygen, electrolyte abnormalities, or a true arrhythmia, which is just the medical term for an abnormal heart rhythm.
What the ER looks for first
The first questions matter a lot.
Did it start suddenly or gradually?
How long did it last?
Was it regular or irregular?
Did it happen at rest or with exertion?
Was there palpitations with dizziness, chest pain, shortness of breath, or fainting?
Those details help narrow the list quickly. A patient with palpitations with chest pain and shortness of breath gets viewed differently than someone who had a few seconds of fluttering after three cold brews and no sleep. Past history matters too. If you have thyroid disease, anemia, heart valve problems, prior arrhythmias, or stimulant use, that changes the concern level immediately.
In the ER, palpitations are less about “did you feel it?” and more about what pattern does this fit?
The EKG is the snapshot everyone wants
One of the first tests ordered is usually an EKG for palpitations. An EKG is a quick tracing of your heart’s electrical activity. It can show whether your heart is beating too fast, too slow, irregularly, or with signs of strain or ischemia, meaning not enough blood flow to the heart muscle.
But here is the catch: an EKG is a snapshot. If your palpitations happened two hours ago and stopped before you arrived, the EKG may look completely normal. That does not mean you imagined it. It just means the heart behaved itself during the photo.
That is why timing matters. If the rhythm is happening while you are on the monitor, great. If not, doctors may still use your symptoms, labs, repeat tracings, and sometimes outpatient heart monitors to connect the dots.
Some causes are common and not dangerous. Others absolutely matter.
A lot of palpitations turn out to be from things that are real but not dangerous.
Palpitations and anxiety are common. So are caffeine, dehydration, alcohol, poor sleep, stress, and isolated extra beats like PVCs or PACs, which are basically little early heartbeats that can feel dramatic but are often benign. Sinus tachycardia is another one. That just means your heart is beating fast for a reason, like dehydration, fever, pain, or blood loss. But some rhythms matter much more.
Atrial fibrillation symptoms often include a fast, irregular heartbeat and can increase stroke risk. That is why AFib in the emergency room gets taken seriously. SVT in the emergency room, or supraventricular tachycardia, is another rhythm where the heart suddenly takes off at a very fast rate and can feel frightening. There are also more dangerous ventricular rhythms, which are less common but much higher stakes.
Then there are the non-rhythm causes that can still stress the heart: palpitations and thyroid problems, anemia from blood loss, low potassium or magnesium, pulmonary embolism, and other metabolic problems. That is the whole challenge with palpitations.
Sometimes it is a stressed heart.
Sometimes it is a misfiring heart.
Sometimes it is both. And the ER’s job is to figure out which one you are dealing with.
THE BOTTOM LINE
• Palpitations can feel like a racing, pounding, skipping, or irregular heartbeat, and the sensation alone does not always tell you the cause
• Many causes are benign, including anxiety, dehydration, caffeine, and isolated extra beats, but serious rhythms like AFib and SVT must also be ruled out
• In the ER, the most important clues are the pattern, the associated symptoms, and what the heart rhythm is doing when it gets captured
Ask the ER Doctor
-
Palpitations are more concerning when they are associated with chest pain, shortness of breath, dizziness, fainting, or a sustained fast or irregular rhythm. Those patterns raise more concern for an arrhythmia or another serious underlying cause.
-
Yes. Anxiety can absolutely cause palpitations, including a racing or pounding heartbeat. The important part is making sure the pattern fits anxiety and not a separate heart rhythm problem.
-
AFib, or atrial fibrillation, is an irregular heart rhythm that can cause palpitations, fatigue, shortness of breath, or dizziness. It can be dangerous because it may increase stroke risk and sometimes causes the heart to beat too fast for too long.
-
An EKG records the heart’s electrical rhythm at that moment. It can show arrhythmias, fast heart rates, irregular rhythms, and signs of strain, but it may miss palpitations that already stopped before the tracing was done.
By Dr. Karim Ali, Emergency Physician