Tachycardia (Fast Heart Rate)

What counts as a fast heart rate

A normal adult resting heart rate is 60 to 100 beats per minute. Children's rates are higher, and a newborn's normal rate can be up to about 160. Fit athletes may rest at 40 to 60. During exercise, a maximum of roughly 220 minus your age is expected and is not tachycardia in the medical sense.

To check: find your pulse at the wrist or neck, count beats for 30 seconds, and double it. Note whether it is regular or irregular.

Types of tachycardia

Sinus tachycardia

This is the most common type. It is the heart's appropriate response to a need for more blood flow. Causes include exercise, stress and anxiety, fever, pain, dehydration, blood loss, anemia, an overactive thyroid, pregnancy, low oxygen, blood clots in the lung, sepsis, caffeine, alcohol withdrawal, nicotine, stimulant drugs and medicines such as asthma inhalers and decongestants. Inappropriate sinus tachycardia and POTS are conditions in which the rate is high without a clear trigger, or rises excessively on standing.

Supraventricular tachycardia

SVT causes sudden episodes of a racing, regular heartbeat, often with pounding in the neck, lightheadedness and anxiety. It is most common in young adults and women. Episodes can stop on their own or with vagal maneuvers.

Atrial fibrillation and flutter

Atrial fibrillation is the most common sustained arrhythmia, increasing with age, high blood pressure, heart disease, obesity, sleep apnea and alcohol use. It can be fast and irregular, or slow and silent.

Ventricular tachycardia, including paroxysmal VT

Paroxysmal ventricular tachycardia means episodes of VT that start and stop by themselves. Short runs (under 30 seconds) are called non-sustained VT. VT usually occurs in people with heart disease: scarring from a previous heart attack, cardiomyopathy or heart failure. It can also occur in inherited conditions such as long QT syndrome, Brugada syndrome and CPVT, and occasionally in structurally normal hearts. Symptoms range from palpitations to dizziness, fainting and cardiac arrest. See paroxysmal ventricular tachycardia.

Symptoms that may come with tachycardia

• heart palpitations: racing, pounding or fluttering
• lightheadedness or dizziness
• shortness of breath
• chest discomfort
• fatigue or reduced exercise ability
• fainting

Some people, especially older adults with atrial fibrillation, have no symptoms.

How doctors find the cause

• ECG: the key test. It identifies the rhythm, especially if recorded during an episode.
• Heart monitors: Holter, patch or event monitors, or an implantable loop recorder, to capture intermittent episodes.
• Blood tests: blood count, thyroid function, electrolytes, kidney function, and sometimes D-dimer, troponin or markers of infection.
• Echocardiogram: checks heart structure and function.
• Exercise test or tilt-table test in selected cases.
• Electrophysiology study: maps the electrical pathways, often combined with ablation.

Treatment

Treatment depends on the type and cause.

• Sinus tachycardia: treat the cause, such as fluids for dehydration, fever control, iron for anemia, thyroid treatment, or reducing caffeine and alcohol.
• SVT: vagal maneuvers, adenosine in hospital, beta-blockers or calcium channel blockers, and catheter ablation, which cures most cases.
• Atrial fibrillation and flutter: rate control, rhythm control (medicines, cardioversion, ablation) and anticoagulation to prevent stroke when indicated.
• Ventricular tachycardia: emergency electrical cardioversion if unstable, antiarrhythmic medicines, ablation and an implantable cardioverter-defibrillator (ICD) for people at risk of sudden death.

Frequently asked questions

When is a fast heart rate dangerous?

A fast heart rate is dangerous when it comes with chest pain, fainting, severe breathlessness or confusion, when it stays above about 150 at rest, or when it is ventricular tachycardia in someone with heart disease. Call 911 or your local emergency number in these situations.

What is paroxysmal ventricular tachycardia?

It is ventricular tachycardia that comes and goes in episodes. It starts in the heart's lower chambers and usually occurs in people with heart muscle damage or inherited rhythm disorders. It can cause palpitations, dizziness or fainting and needs specialist cardiology care.

Can anxiety cause tachycardia?

Yes. Anxiety and panic release adrenaline, which causes sinus tachycardia, a fast but normal rhythm. It usually builds and settles gradually. If episodes start and stop suddenly or happen without stress, an ECG and heart monitor can rule out an arrhythmia.

What is a normal resting heart rate?

For adults, 60 to 100 beats per minute at rest is normal. Many healthy, active adults are in the 50s or 60s. A resting rate consistently over 100 without an obvious cause, such as fever or caffeine, should be checked by a doctor.