An extrasystole is an extra heartbeat that fires earlier than expected, briefly disrupting your normal rhythm. You might feel it as a skipped beat, a flutter, or a sudden thump in your chest. Extrasystoles are extremely common, and in most people they’re completely harmless.
How Extrasystoles Work
Your heart has a built-in pacemaker, a cluster of cells in the upper right chamber that sends out a regular electrical signal to keep each beat on time. An extrasystole happens when a different group of cells somewhere else in the heart fires off its own signal before the pacemaker does. This creates an early, “extra” contraction that sneaks in ahead of the next scheduled beat.
There are two main types, based on where that rogue signal originates. Premature atrial contractions (PACs) start in the upper chambers of the heart. Premature ventricular contractions (PVCs) start in the lower pumping chambers. PVCs tend to produce a more noticeable sensation because the ventricles are responsible for pumping blood out to the body, and when they contract early, they haven’t had time to fill completely. Both types are followed by a brief pause before the next normal beat, which is often what creates that unsettling “skipped beat” feeling.
What They Feel Like
People describe extrasystoles in a variety of ways: a flip-flopping sensation, a pounding beat, a flutter, or the feeling that the heart momentarily stopped. The sensation often comes not from the early beat itself but from the stronger-than-usual beat that follows the pause, as the heart contracts with a bit more force after the brief delay. You can feel extrasystoles in your chest, throat, or neck. They can happen during physical activity or while you’re sitting still, and many people notice them more at night when lying quietly in bed and there are fewer distractions.
Common Triggers
Extrasystoles can appear without any obvious cause, but several factors make them more likely. The most frequently reported triggers include alcohol, caffeine, exercise, and lack of sleep. Emotional stress and anxiety are also well-established contributors. Smoking increases the risk, and the combination of smoking with heavy alcohol use can compound the effect.
Mineral imbalances play a significant role too. Low magnesium levels, in particular, are linked to more frequent ventricular extrasystoles. In one study, patients given intravenous magnesium saw a significant drop in the frequency of extra beats, while potassium infusions alone did not produce the same effect. Magnesium turns out to be essential for the body to properly use potassium at the cellular level, so even if your potassium intake is adequate, a magnesium shortfall can throw off the heart’s electrical stability. Dehydration, intense exercise, and diuretic medications can all deplete these minerals.
When Extrasystoles Are Harmless
The vast majority of extrasystoles are benign. Nearly everyone experiences them at some point, and many people have dozens or even hundreds per day without knowing it. If your heart is otherwise structurally normal, occasional extra beats carry no meaningful risk. They tend to come and go in clusters, sometimes appearing frequently for days or weeks and then disappearing entirely.
The key indicator doctors use is called PVC burden: the percentage of your total heartbeats in a day that are premature. Most people who undergo monitoring fall well below the threshold for concern. Only about 9% of patients getting Holter monitors (portable devices that record heart rhythm over 24 hours) show a PVC rate above 5%, and just 5% show rates above 10%.
When They Become a Concern
At higher frequencies, extrasystoles can start to weaken the heart over time. A PVC burden above 15% is considered a strong predictor for developing a form of heart muscle weakening caused by the extra beats themselves. Some research places the threshold even higher, at 24% to 26%, but a cutoff of 16% has shown 90% sensitivity and 85% specificity for identifying patients at risk. One patient in a published case series had extrasystoles making up roughly 40% of all heartbeats in a day, enough to warrant treatment even without symptoms.
Certain warning signs suggest an extrasystole could be part of a more serious rhythm problem. Fainting without any warning signs (no nausea, no lightheadedness beforehand) points more toward a dangerous arrhythmia than a simple vasovagal episode. By contrast, fainting associated with prolonged standing, hot environments, emotional stress, or the sight of blood is typically neurally mediated and less concerning. If you experience sudden loss of consciousness, chest pain, or sustained rapid heartbeat alongside your extra beats, those warrant urgent evaluation.
How Extrasystoles Are Diagnosed
A standard electrocardiogram (ECG) can catch extrasystoles if they happen during the recording, but since they often come and go unpredictably, a Holter monitor worn for 24 to 48 hours gives a much clearer picture. The monitor captures every beat over that period, allowing your doctor to calculate your PVC burden and look at the timing and pattern of the extra beats. In some cases, an event monitor worn for weeks is needed if extrasystoles are infrequent but bothersome.
If the PVC burden is elevated, an echocardiogram (an ultrasound of the heart) is typically performed to check whether the heart’s pumping function has been affected. This combination of rhythm data and imaging tells doctors whether the extrasystoles are an annoyance or a problem that needs treatment.
Lifestyle Changes That Help
For most people, reducing triggers is the most effective first step. Cutting back on alcohol and caffeine, improving sleep, managing stress, and staying well hydrated can noticeably reduce extrasystole frequency. Ensuring adequate magnesium intake through foods like nuts, seeds, leafy greens, and whole grains may also help, particularly if you take diuretics or sweat heavily through exercise. Quitting smoking, if applicable, removes another major contributor.
Medical Treatment Options
When lifestyle changes aren’t enough and symptoms are persistent or the PVC burden is high enough to risk heart muscle damage, medication is the standard next step. The two main drug classes used are beta-blockers and calcium channel blockers. Both work by slowing the heart’s electrical activity and making it less susceptible to those premature signals. There’s no clear consensus on which class works better, and the choice often depends on individual factors like resting heart rate, blood pressure, and side effect tolerance.
If medications don’t control the problem, or if a patient can’t tolerate them, catheter ablation is an option. This is a minimally invasive procedure where a thin wire is threaded through a blood vessel to the heart, and the small patch of tissue generating the rogue signals is carefully neutralized with targeted energy. In a real-world study, the procedure achieved primary success in about 76% of cases, with roughly 70% to 75% maintaining that success at three-month follow-up. Another 23% of cases were partially successful. The procedure works regardless of where in the heart the extrasystoles originate, and it’s considered safe for patients whose symptoms are disruptive or whose PVC burden puts them at risk for cardiomyopathy.
For the small number of people who need ablation, the results can be essentially curative, eliminating or dramatically reducing extra beats that medications only partially controlled.