Tachycardia
A faster-than-normal heart rate
Quick Facts
- Type: Cardiovascular symptom
- Definition: Resting heart rate over 100 bpm (adults)
- Common causes: Exercise, stress, fever, arrhythmia, thyroid
- Urgent if: Chest pain, fainting, or severe breathlessness
Overview
Tachycardia is the medical term for a heart rate that is faster than normal, generally more than 100 beats per minute at rest in adults. A fast heart rate is a normal and healthy response to exercise, excitement, fear, or fever, when the body needs more blood flow. Tachycardia is a concern when it happens at rest without a clear reason, or when it comes with symptoms such as chest pain, dizziness, or breathlessness.
Some forms of tachycardia start in the upper chambers of the heart and others in the lower chambers, and they range from harmless to serious. People may feel their heart racing or pounding (palpitations), while others have no sensation at all. Because tachycardia can be a sign of a heart rhythm disorder or another condition, a fast resting heart rate that recurs or causes symptoms should be evaluated.
Not all fast heartbeats are the same. Some begin and end gradually, as the heart simply responds to exercise, stress, or fever, while others switch on and off abruptly, which is more typical of certain rhythm disorders. The rhythm may feel regular or irregular, and episodes can last seconds or much longer. Paying attention to how an episode starts, how it feels, and how it ends gives useful clues that help a doctor tell a normal response from one that needs treatment.
Common Causes
Tachycardia can result from normal triggers or from underlying conditions:
- Physical and emotional factors: Exercise, stress, anxiety, pain, fever, and dehydration normally speed the heart.
- Stimulants: Caffeine, nicotine, alcohol, energy drinks, and some medications.
- Heart rhythm disorders: Such as atrial fibrillation and other forms of arrhythmia, where electrical signals fire too quickly.
- Overactive thyroid: Hyperthyroidism commonly raises the resting heart rate.
- Anemia or blood loss: The heart beats faster to deliver enough oxygen.
- Infection, low blood sugar, or heart disease: Each can drive a fast heart rate.
Electrolyte imbalances and some medications can also contribute.
Associated Symptoms
Tachycardia may occur alone or with symptoms that signal the cause and urgency:
- Palpitations, a racing, fluttering, or pounding feeling in the chest
- Chest pain or tightness
- Shortness of breath
- Dizziness, lightheadedness, or fainting
- Sweating, weakness, or anxiety
- Fatigue
A fast heart rate together with chest pain, severe breathlessness, fainting, or confusion is a warning combination that needs urgent medical evaluation, as it may reflect a dangerous rhythm or another serious problem.
Diagnosis & Evaluation
A doctor will measure your heart rate and rhythm, check blood pressure, and ask about triggers and symptoms. Tests may include:
- Electrocardiogram (ECG): Records the heart's electrical activity to identify the type of tachycardia.
- Holter or event monitor: A wearable device that records the heartbeat over time to catch intermittent episodes.
- Blood tests: To check thyroid function, anemia, electrolytes, and infection.
- Echocardiogram: An ultrasound to assess the heart's structure and function.
These tests distinguish a normal response from an arrhythmia or another condition that needs treatment.
Treatment & Management
Treatment depends on the cause and type of tachycardia and the symptoms it causes:
- Reducing triggers: Cutting back on caffeine, alcohol, and nicotine, managing stress, treating fever, and staying hydrated.
- Treating underlying conditions: Such as correcting anemia, managing an overactive thyroid, or treating infection.
- Medications: Drugs that slow the heart rate or control rhythm for certain arrhythmias.
- Procedures: Cardioversion or catheter ablation for persistent or dangerous rhythm disorders, performed by a specialist.
- Vagal maneuvers: Techniques a doctor may teach to slow certain fast rhythms.
Do not stop heart or thyroid medicines on your own, and seek medical advice for any new or recurrent fast heartbeat.
When to See a Doctor
See a doctor if you have repeated episodes of a racing heart at rest, a fast heartbeat that keeps recurring, or one that comes with dizziness or breathlessness even if it passes on its own.
Call emergency services right away if tachycardia occurs with chest pain or pressure, severe shortness of breath, fainting or near-fainting, or confusion, or if a very fast heartbeat does not slow down. These can signal a serious heart rhythm problem or another emergency that needs immediate treatment.
Frequently Asked Questions
What is tachycardia?
Tachycardia is a heart rate faster than normal, generally over 100 beats per minute at rest in adults. It is normal during exercise or stress but can be a concern at rest, especially with chest pain, dizziness, or breathlessness.
What causes tachycardia at rest?
Common causes include caffeine, stress, anxiety, dehydration, fever, and lack of sleep, as well as arrhythmias, an overactive thyroid, anemia, and infection. Recurrent resting tachycardia deserves a medical check, often with an ECG.
Is tachycardia dangerous?
Often it is harmless and settles on its own. It can be dangerous when it is very fast, sustained, or paired with chest pain, fainting, or severe breathlessness, which require emergency care to rule out a serious rhythm problem.
How is tachycardia treated?
Treatment depends on the cause. It may include reducing stimulants, treating an underlying condition such as a thyroid problem, medications to control the rhythm, or procedures like ablation for persistent arrhythmias.
When should I get emergency help for a fast heartbeat?
Call for emergency help if a fast heartbeat comes with chest pain, severe shortness of breath, fainting, or confusion, or if a very rapid pulse does not slow down. These may indicate a dangerous heart rhythm.
References
- American Heart Association. Tachycardia: Fast Heart Rate.
- Mayo Clinic. Tachycardia — Symptoms and causes.
- National Heart, Lung, and Blood Institute (NHLBI). Arrhythmias.
- MedlinePlus, U.S. National Library of Medicine. Rapid heartbeat.