Tachycardia is a heart rate faster than 100 beats per minute (bpm) at rest. A normal resting heart rate for adults falls between 60 and 100 bpm, so tachycardia begins where that upper boundary ends. Some episodes are brief and harmless, like your heart racing after climbing stairs or drinking coffee. Others signal an underlying heart problem that needs treatment.
Worth noting: the 100 bpm cutoff has been used for decades, but some cardiologists argue it’s too generous. A paper in the American Heart Association journal Hypertension suggested that a resting heart rate above 85 bpm in men may already carry increased cardiovascular risk, even if it doesn’t technically qualify as tachycardia.
How It Feels During an Episode
The hallmark sensation is palpitations: a racing, pounding, or fluttering feeling in your chest. Some people describe it as their heart “flopping.” Beyond that, common symptoms include lightheadedness, shortness of breath, chest pain, and in more serious episodes, fainting. Many people also notice a visibly rapid pulse in their neck or wrist.
Not everyone with tachycardia feels symptoms. Some people only discover it during a routine checkup or when wearing a heart monitor for an unrelated reason. The severity of symptoms generally depends on how fast the heart is beating, how long the episode lasts, and whether you have other heart conditions.
Types Based on Where It Starts
Tachycardia is grouped by where in the heart the abnormal electrical signals originate. This distinction matters because it determines how serious the condition is and how it’s treated.
Sinus Tachycardia
This is the most straightforward type. Your heart’s natural pacemaker (the sinus node) simply fires faster than usual. Exercise, fever, anxiety, dehydration, and stimulants like caffeine can all cause it. Sinus tachycardia is usually a normal response to something happening in your body, not a problem with the heart itself. It resolves when the trigger goes away.
Supraventricular Tachycardia
Supraventricular tachycardia (SVT) involves abnormal electrical circuits in the upper chambers of the heart. The most common form accounts for over 60% of cases seen in electrophysiology labs: it happens when electrical signals loop between two pathways near the center of the heart, one conducting fast and one conducting slow, creating a short circuit that drives the heart rate up rapidly. Other forms involve extra electrical connections between the upper and lower chambers that shouldn’t be there, left over from fetal development. SVT episodes often start and stop suddenly, which is a useful clue when describing them to a doctor.
Ventricular Tachycardia
This type originates in the lower chambers, which are responsible for pumping blood to your lungs and body. Ventricular tachycardia is the most dangerous form because it can interfere with the heart’s ability to pump effectively. In some cases, it can deteriorate into a life-threatening rhythm. It’s more common in people who have existing heart disease or structural heart problems.
Common Causes and Triggers
Tachycardia has a long list of potential causes, ranging from completely benign to medically significant. On the everyday side: caffeine, alcohol, stress, lack of sleep, dehydration, and physical exertion all raise heart rate. So do fever and pain. These triggers produce sinus tachycardia that resolves on its own.
Medical causes include thyroid problems (an overactive thyroid is a classic culprit), anemia, low blood pressure, infections, and heart conditions like valve disease or prior heart attack damage. Certain medications, particularly decongestants and some asthma drugs, can also push heart rate up. Recreational stimulants like cocaine and amphetamines are well-known triggers for dangerous tachycardia episodes.
How Tachycardia Is Diagnosed
The starting point is a standard 12-lead electrocardiogram (ECG), which records your heart’s electrical activity for about 10 seconds. If you’re having an episode during the test, the ECG can usually identify the type of tachycardia right away. The challenge is that many people have episodes that come and go, so a brief ECG in the office may look completely normal.
When that happens, the next step is ambulatory monitoring. A Holter monitor, which you wear for 24 to 48 hours, continuously records your heart rhythm while you go about daily life. This remains the gold standard for catching intermittent episodes. For less frequent episodes, longer-term options include adhesive patch monitors worn for up to two weeks or even small implantable loop recorders that sit under the skin and monitor for months.
Your doctor will also typically check bloodwork, including thyroid function and a basic metabolic panel, and may order an echocardiogram (an ultrasound of the heart) to look for structural problems. If the type of tachycardia is still unclear after these tests, an electrophysiology study, where thin wires are threaded into the heart to map its electrical pathways directly, can provide a definitive diagnosis.
Treatment Options
Treatment depends entirely on the type and severity. Sinus tachycardia from an identifiable trigger, like too much caffeine or an overactive thyroid, is treated by addressing the underlying cause. No heart-specific treatment is needed.
For SVT, many episodes can be stopped in the moment with vagal maneuvers: techniques that stimulate the vagus nerve and slow the heart. Bearing down as if having a bowel movement, splashing ice-cold water on your face, or coughing forcefully can sometimes break an episode within seconds. Medications that slow electrical conduction through the heart are used for people who have frequent episodes or whose symptoms don’t respond to vagal maneuvers.
Catheter ablation is often the most effective long-term solution for SVT and certain types of ventricular tachycardia. During the procedure, a thin tube is guided through a blood vessel into the heart, and targeted energy is used to destroy the tiny area of tissue responsible for the abnormal electrical signals. Ablation can often cure the arrhythmia completely, eliminating both symptoms and the need for ongoing medication. It’s a well-established procedure with high success rates for SVT in particular.
Ventricular tachycardia in people with heart disease may require more aggressive management, including an implantable defibrillator that can detect and correct dangerous rhythms automatically.
Long-Term Risks of Untreated Tachycardia
Occasional brief episodes of SVT in an otherwise healthy heart are generally not dangerous, though they can be disruptive and anxiety-provoking. The stakes are higher when tachycardia is frequent, prolonged, or occurs alongside other cardiovascular problems.
A persistently elevated heart rate forces the heart to work harder with less time to fill between beats. Over time, this reduces the heart’s ability to pump efficiently and can lead to heart failure. It also decreases blood flow through the coronary arteries, promoting the buildup of arterial plaque and increasing the risk of heart attack. Research has linked chronically elevated heart rate to higher risk of coronary heart disease, stroke, and sudden cardiac death, particularly in people who also have high blood pressure. The combination of hypertension and elevated heart rate appears especially harmful, accelerating damage to blood vessel walls and making existing plaques more likely to rupture.
Tachycardia in Children
Heart rate norms are higher in children than in adults, so the thresholds for tachycardia are different. In infants, SVT is typically suspected when the heart rate exceeds 200 bpm. In older children and teenagers, the threshold is around 160 bpm. Infants with SVT may not be able to communicate symptoms, so parents might notice poor feeding, unusual fussiness, or pale skin instead. SVT is the most common abnormal fast rhythm in children, and it responds well to treatment, including ablation in older kids.
Lifestyle Factors That Help
Regular physical activity is one of the most effective ways to improve your heart’s overall rhythm stability. Exercise strengthens the heart muscle and lowers resting heart rate over time by reducing the nervous system’s “fight or flight” activation. A diet built around whole grains, fruits, vegetables, and legumes rather than refined carbohydrates also supports healthier heart function.
If you experience recurrent episodes, tracking your triggers can be genuinely useful. Keep a simple log of what you were doing, eating, or drinking before an episode. Common patterns that emerge include alcohol consumption (even moderate amounts in some people), poor sleep, and high stress periods. Reducing or eliminating these triggers won’t cure a structural electrical problem, but it can dramatically reduce how often episodes occur.