Heart palpitations are a sensation you feel; an arrhythmia is an actual change in your heart’s rhythm. That distinction matters because you can have palpitations without any arrhythmia, and you can have an arrhythmia without ever feeling it. In about 31% of people who report palpitations, the cause turns out to be psychological (stress, anxiety, or depression) rather than a rhythm problem at all.
Palpitations Are a Symptom, Not a Diagnosis
Palpitations are simply your awareness of your own heartbeat in a way that feels abnormal. People describe them as fluttering, racing, pounding, or a sensation that the heart “skipped a beat.” They are subjective: what you notice depends on your body, your attention, and your emotional state. Sedentary or anxious people tend to notice heartbeat irregularities more readily, while active, relaxed people often don’t register the same cardiac events at all.
The physical sensation comes from abnormal movement of the heart inside the chest. When your heart has an extra beat (called a premature beat), the next normal beat is often stronger than usual. That forceful contraction is what you actually feel, sometimes instead of the extra beat itself, sometimes in addition to it. This is why a single skipped beat can produce a noticeable “thump” that seems out of proportion to what happened.
Arrhythmia Is a Measurable Rhythm Problem
An arrhythmia is any abnormal heart rhythm or beat, confirmed by an electrical recording of the heart. It’s an objective finding: either the electrical signals in your heart are firing in an irregular pattern or they aren’t. Common types include:
- Atrial fibrillation (AFib): chaotic electrical signals in the upper chambers cause an irregular and often rapid heartbeat. This accounts for roughly 16% of palpitation cases.
- Supraventricular tachycardia (SVT): a sudden, rapid heartbeat originating above the lower chambers that starts and stops abruptly. Found in about 10% of palpitation cases.
- Premature ventricular contractions (PVCs): extra beats originating in the lower chambers that feel like a skipped beat. These are extremely common and usually harmless.
- Ventricular tachycardia: a fast rhythm from the lower chambers that can be dangerous. This is the least common cause, found in about 2% of palpitation cases.
The critical point is that most people who have arrhythmias don’t actually feel them. Some people walk around with complex rhythm disturbances and never report a single palpitation. Others feel every minor extra beat their heart produces. Your perception is not a reliable indicator of what’s happening electrically.
What Causes Palpitations When There’s No Arrhythmia
Because palpitations are a sensation, many things besides heart rhythm problems can trigger them. The most common non-cardiac causes include strong emotional responses like stress, anxiety, or panic attacks. Stimulants are another frequent trigger: caffeine, nicotine, cocaine, amphetamines, and even cold medications containing pseudoephedrine can all make you feel your heart racing or pounding.
Hormonal shifts play a role too. Changes associated with menstruation, pregnancy, or menopause can bring on palpitations. An overactive or underactive thyroid gland affects heart rate and can produce a persistent awareness of your heartbeat. Fever, strenuous exercise, and depression round out the list. In all of these cases, the heart may be beating faster or harder than normal, but the underlying rhythm itself is not disordered.
How Doctors Tell the Difference
The standard tool for distinguishing a benign palpitation from an arrhythmia is an electrocardiogram (ECG), a recording of your heart’s electrical activity through sensors on your skin. A 12-lead ECG is the reference standard for determining whether palpitations have an arrhythmic cause. The challenge is that your heart needs to be doing something abnormal at the moment the recording is happening.
If your palpitations come and go, a single ECG in a doctor’s office may look perfectly normal. That’s where longer monitoring comes in, and the choice of device depends on how often you have symptoms:
- Holter monitor (24 to 48 hours): best for daily or near-daily symptoms. It catches rhythm problems with good specificity, but its sensitivity is low, only around 10 to 15%, because it may miss events that don’t happen during the recording window.
- Event monitor (weeks to a month): better for symptoms that occur weekly or monthly. You activate it when you feel palpitations. Sensitivity improves to about 50 to 60%.
- Loop monitor, external or implantable (weeks to 36 months): the most sensitive option, with diagnostic yields of 70 to 90%. An implantable version can stay in place for up to three years, catching even the rarest episodes.
An echocardiogram (an ultrasound of the heart) is added when there’s suspicion of structural heart disease, such as thickened heart muscle, valve problems, or signs of prior heart damage. Not everyone with palpitations needs one.
When Palpitations Signal Something Serious
Most palpitations are harmless. But certain accompanying symptoms suggest the underlying cause could be a dangerous arrhythmia. A sudden collapse or loss of consciousness warrants an immediate trip to the emergency department. Palpitations paired with dizziness or lightheadedness are another red flag, as is chest pain.
Context matters too. Palpitations that occur only during intense physical activity, that come with shortness of breath, or that run in a family with a history of sudden cardiac death deserve a thorough workup. People with known structural heart disease are at higher risk of having their palpitations caused by a clinically significant arrhythmia rather than a benign trigger.
The Overlap, and Why It Confuses People
The reason this distinction is so confusing is that palpitations and arrhythmias overlap without matching up neatly. You can have palpitations caused by an arrhythmia, palpitations caused by caffeine with a perfectly normal rhythm, or a silent arrhythmia you never feel. The two concepts sit on different axes: one is what you experience, the other is what your heart is electrically doing.
Roughly 28% of people who report palpitations turn out to have a significant arrhythmia (AFib, SVT, or ventricular tachycardia). Another 6% have a medication or substance as the culprit. And for nearly a third, the cause is psychiatric or stress-related, with no rhythm abnormality at all. That breakdown is why doctors don’t treat palpitations themselves. They investigate what’s behind them, because the symptom alone tells you very little about whether your heart is in trouble.