An irregular heartbeat is called an arrhythmia. The term covers any problem with the rate or rhythm of your heartbeat, whether your heart beats too fast, too slow, or in an unpredictable pattern. A normal resting heart rate for adults falls between 60 and 100 beats per minute, and arrhythmias happen when the electrical signals that control your heartbeat go off course.
Types of Arrhythmias
Arrhythmia is the umbrella term, but several specific types fall underneath it, each with its own name depending on what the heart is doing.
Tachycardia refers to a resting heart rate faster than 100 beats per minute. Your heart’s electrical signals fire too rapidly, which can feel like a racing or pounding sensation in your chest.
Bradycardia is the opposite: a resting heart rate slower than 60 beats per minute. One important exception here is that well-trained athletes often have resting rates closer to 40 beats per minute, which is normal for them.
Atrial fibrillation (AFib) is the most common type of arrhythmia. During AFib, the upper chambers of the heart quiver chaotically rather than contracting in a steady rhythm, producing rates that can exceed 400 beats per minute. Those beats aren’t pumping blood effectively, which is why AFib raises the risk of blood clots and stroke.
Premature contractions are what most people experience as a “skipped beat.” Your heart doesn’t actually skip. Instead, an extra beat fires early, followed by a pause that makes the next normal beat feel unusually forceful. Premature beats starting in the upper chambers are called premature atrial contractions (PACs), while those starting in the lower chambers are premature ventricular contractions (PVCs). These are extremely common, occur in children and teenagers, and typically resolve on their own without treatment.
What Arrhythmias Feel Like
Many arrhythmias produce no noticeable symptoms at all. When they do, the sensations vary widely depending on the type. Common experiences include a fluttering, pounding, or racing feeling in the chest, a heartbeat that feels unusually slow, lightheadedness or dizziness, unusual fatigue, sweating, and anxiety that seems to come out of nowhere.
More serious warning signs include chest pain, shortness of breath, and fainting. These warrant emergency medical attention because they can signal a dangerous rhythm disturbance affecting blood flow to the brain or body.
Common Causes and Triggers
Some arrhythmias stem from underlying health conditions: high blood pressure, heart disease, scarring from a previous heart attack, electrolyte imbalances (particularly low potassium or magnesium), sleep apnea, or thyroid problems. Genetic factors also play a role in certain rhythm disorders.
Temporary arrhythmias often have lifestyle triggers. Caffeine, alcohol, and stress are the most common culprits. There’s even a phenomenon called “holiday heart syndrome,” where a combination of heavy drinking (typically five or more alcoholic beverages), large salty meals, and holiday stress pushes an otherwise healthy heart into an irregular rhythm. The threshold varies from person to person, and these episodes usually resolve once the trigger is removed.
How Arrhythmias Are Diagnosed
The primary tool is an electrocardiogram (ECG or EKG), a quick test that records the electrical activity of the heart and shows whether it’s beating too fast, too slow, or irregularly. The challenge is that many arrhythmias come and go, so a single ECG may not catch them.
For intermittent symptoms, doctors use portable monitors. A Holter monitor is a wearable ECG device worn for a day or more that records your heart’s activity during normal daily life. An event recorder serves the same purpose but can be worn for up to 30 days, waiting to capture an episode. For truly rare episodes, an implantable loop recorder can be placed under the skin in the chest area to continuously monitor your heart’s electrical signals over months.
Other diagnostic tools include stress tests, where your heart is monitored while you exercise on a treadmill or stationary bike, and tilt table tests for people who’ve experienced fainting spells. In some cases, a more invasive procedure called an electrophysiology (EP) study maps the exact location of faulty electrical signals inside the heart using thin, flexible tubes guided through a blood vessel.
Treatment Options
Treatment depends entirely on the type of arrhythmia, how severe it is, and what’s causing it. Many arrhythmias, particularly occasional premature beats, need no treatment at all.
When the underlying cause is something like an electrolyte deficiency, high blood pressure, or thyroid disease, treating that condition often resolves the rhythm problem. Supplements to restore potassium or magnesium levels can be enough in some cases.
For fast heart rhythms, several categories of medication can slow or regulate electrical signals in the heart. These include beta blockers, calcium channel blockers, and other drugs that target specific electrical pathways. Each comes with its own set of potential side effects, from fatigue and digestive issues to low blood pressure, so the choice depends on your particular situation.
For slow heart rhythms, a pacemaker (a small device implanted under the skin that sends electrical pulses to keep your heart beating at a normal rate) is the standard approach. For people at high risk of life-threatening fast rhythms, an implantable cardioverter-defibrillator (ICD) can detect dangerous patterns and deliver a corrective shock automatically.
Catheter ablation is a procedure that destroys the tiny area of heart tissue responsible for sending abnormal electrical signals. It’s commonly used when medication isn’t effective or when the source of the arrhythmia can be precisely located. Cardioversion, which uses external electric shocks to reset the heart’s rhythm, is another option for restoring a normal pattern.
For certain episodes of fast heart rate, simple physical techniques called vagal maneuvers can help. These include holding your breath and bearing down (the Valsalva maneuver), coughing, or placing an ice-cold towel on your face. These actions stimulate a nerve that naturally slows the heart rate and can sometimes stop an episode without any medical intervention.