Tachycardia is a heart rate faster than 100 beats per minute while you’re at rest. A normal resting heart rate falls between 60 and 100 beats per minute, so tachycardia means something is pushing your heart to beat faster than it should when you’re not exercising or exerting yourself. It can be a temporary response to stress or caffeine, or it can signal a problem with the heart’s electrical system that needs treatment.
Why Your Heart Speeds Up
Your heart has a built-in pacemaker, a small cluster of cells in the upper right chamber that sends electrical signals to coordinate each beat. Tachycardia happens when something disrupts those signals or forces the heart to work harder than normal. The causes range from completely harmless to serious.
The most common and least concerning form is sinus tachycardia, where the heart speeds up in response to something your body is dealing with: fear, nervousness, fever, intense exercise, dehydration, or certain drugs (including too much caffeine). In these cases, the fast heart rate is a symptom, not the core problem. Once the trigger goes away, the heart rate returns to normal.
Less common causes include anemia, heavy bleeding, an overactive thyroid, and damaged heart muscle. These conditions force the heart to compensate by beating faster, either to move oxygen more efficiently or to make up for weakened pumping ability.
Types of Tachycardia
Not all fast heart rhythms are the same. The type depends on where in the heart the abnormal electrical activity starts, and this distinction matters because it determines how dangerous the condition is and how it’s treated.
Supraventricular Tachycardia
Supraventricular tachycardia (SVT) starts in the upper chambers of the heart, called the atria. The most common subtype, paroxysmal supraventricular tachycardia, causes extra heartbeats due to a glitch in the electrical signals traveling from the upper chambers to the lower ones. Episodes tend to start and stop suddenly. SVT is usually not dangerous and often affects young, otherwise healthy people. It can be triggered by vigorous physical activity.
Ventricular Tachycardia
Ventricular tachycardia originates in the heart’s lower chambers, the ventricles, which are responsible for pumping blood out to the body. This type is more serious. A few beats of ventricular tachycardia may not cause problems, but if it lasts more than a few seconds, it can deteriorate into ventricular fibrillation, a chaotic rhythm where the heart essentially stops pumping. Ventricular arrhythmias usually require immediate medical attention.
What Tachycardia Feels Like
Some people with tachycardia feel nothing at all, especially if their heart rate is only slightly elevated. When symptoms do appear, the most recognizable one is palpitations: a fluttering, pounding, or racing sensation in your chest. You might feel like your heart is “skipping” or hammering against your ribs.
Other common symptoms include dizziness or lightheadedness, shortness of breath, and feeling unusually tired. In more severe episodes, some people experience chest pain or tightness, near-fainting, or actual fainting. The severity of symptoms depends on how fast the heart is beating, how long it stays elevated, and whether you have any underlying heart conditions.
What Happens if It Goes Untreated
Brief, occasional episodes of tachycardia, like the kind triggered by stress or caffeine, generally don’t cause lasting harm. But a heart that stays fast for extended periods has to work much harder than normal. Over time, this extra workload can weaken the heart muscle, reducing its ability to pump blood effectively. This is called tachycardia-induced cardiomyopathy, and it can progress to heart failure if the underlying rhythm problem isn’t corrected.
Certain types of tachycardia, particularly atrial fibrillation (a rapid, irregular rhythm in the upper chambers), also increase the risk of blood clots forming inside the heart. If a clot breaks loose and travels to the brain, it causes a stroke. People with persistent atrial fibrillation often need blood-thinning medication to reduce that risk.
How It’s Diagnosed
An electrocardiogram (ECG) is the primary tool for diagnosing tachycardia and identifying its type. The test records the heart’s electrical activity through sensors placed on the skin and produces a tracing that shows the pattern and timing of each heartbeat. Doctors look at the shape and width of the electrical waves to figure out where the abnormal signals are coming from. About 80% of fast rhythms with a wide, stretched-out pattern on the ECG originate in the ventricles, while the remaining 20% start in the upper chambers but travel through an unusual pathway.
If your episodes are infrequent, a standard ECG in the office might not catch them. In that case, you may wear a portable heart monitor for 24 hours to several weeks to record your rhythm during daily life. The goal is to capture an episode as it happens so the type can be identified precisely.
Simple Techniques That Can Slow Your Heart
For SVT episodes, a set of physical techniques called vagal maneuvers can sometimes reset the heart’s rhythm on the spot. These work by stimulating the vagus nerve, which runs from the brain to the abdomen and helps regulate heart rate. Effective maneuvers include coughing forcefully, bearing down as if you’re having a bowel movement, or placing an ice pack on your face. These actions trigger a reflex that slows electrical conduction through the heart.
Another technique, carotid sinus massage, involves pressing on a specific spot on the neck near the carotid artery. This should only be done by an experienced healthcare professional, never on your own, because incorrect pressure can cause complications.
Medications for Ongoing Management
When tachycardia recurs or needs long-term control, medications are typically the first step. The most commonly used drugs work by slowing the electrical signals in the heart or reducing the heart’s sensitivity to stress hormones. One class blocks calcium from entering heart and artery cells. Since calcium makes those cells contract more forcefully, blocking it allows blood vessels to relax and can slow the heart rate. Another class blocks the effects of adrenaline on the heart, which lowers both heart rate and blood pressure.
The choice of medication depends on the type of tachycardia, your overall health, and how well you tolerate the drug. Some people stay on medication indefinitely, while others use it as a bridge until a more permanent fix is in place.
Catheter Ablation
For tachycardias caused by a specific electrical “short circuit” in the heart, catheter ablation offers a potential cure. During the procedure, a thin tube is threaded through a blood vessel (usually in the groin) into the heart. The tip delivers energy, either radiofrequency heat or extreme cold, to destroy the tiny patch of tissue responsible for the abnormal signals.
Success rates vary by type. For SVT, catheter ablation works 90% to 95% of the time, making it one of the most reliable procedures in cardiology. For atrial fibrillation, atrial tachycardia, and ventricular tachycardia, the success rate drops to 60% to 80%, and some people need a second procedure. Risks include blood clots, damage to blood vessels or heart valves, infection, bleeding, stroke, and in rare cases the need for a permanent pacemaker. Most people recover within a few days and return to normal activity within a week.
Lifestyle Changes That Help
For sinus tachycardia and milder forms of SVT, lifestyle adjustments can significantly reduce how often episodes occur. Cutting back on caffeine is one of the most straightforward changes. Staying well hydrated matters too, since even mild dehydration forces the heart to beat faster to maintain blood pressure. Managing stress through regular exercise, adequate sleep, and relaxation techniques can lower your baseline heart rate over time. If you use stimulant medications or recreational drugs, those are worth discussing with a doctor, as they’re common but often overlooked triggers.
Tracking your episodes, including what you were doing, eating, or drinking beforehand, can help you and your doctor identify your personal triggers and decide whether further treatment is needed.