What is tachycardia?
Tachycardia refers to a heart rate that is faster than normal. A normal resting heart rate for adults ranges from 60 to 100 beats per minute. Tachycardia is generally defined as a resting heart rate above 100 beats per minute. During exercise or as a normal response to physiological stress, it is common for the heart rate to exceed 100 beats per minute. However, when the resting heart rate is persistently above 100 bpm, this typically indicates tachycardia.
Causes of tachycardia
There are many potential causes of tachycardia, including:
- Physiological stress or exercise
- Low blood pressure
- Thyroid disorders
- Drugs and stimulants, such as caffeine
- Heart disease, such as valve disorders
- Arrhythmias or abnormal heart rhythms
In many cases, the cause is benign. However, sometimes tachycardia can indicate an underlying heart condition or arrhythmia that requires treatment.
When is tachycardia concerning?
Most episodes of tachycardia are not dangerous. Brief increases in heart rate during exercise or stress are normal and harmless.
However, prolonged tachycardia may potentially lead to complications if left untreated. Tachycardia is typically considered concerning when:
- The resting heart rate is persistently over 100 bpm
- It occurs without an apparent trigger such as exercise or stress
- It lasts longer than a few seconds or minutes
- It is accompanied by chest pain, dizziness, shortness of breath, or fainting
Some specific types of tachycardia that often require treatment include:
- Supraventricular tachycardia (SVT) – Episodes of a rapid heart rate, often over 150 bpm, originating from above the ventricles.
- Ventricular tachycardia – A rapid heart rhythm originating from the lower chambers of the heart.
- Atrial fibrillation – An irregular and often rapid heart rate caused by chaotic electrical signals in the atria.
When to see a doctor
It is recommended to see a doctor promptly if you experience any of the following:
- Resting heart rate consistently over 100 bpm
- Racing or fluttering sensations in the chest
- Tachycardia that starts and stops suddenly
- Lightheadedness, dizziness or fainting
- Shortness of breath or chest pain
- Palpitations or sensation of a skipped beat
Prompt medical evaluation is advised to determine the cause of tachycardia and assess the need for treatment. Leaving certain types of arrhythmias untreated raises the risk of complications like stroke or heart failure.
How tachycardia is diagnosed
To diagnose tachycardia, doctors typically review symptoms and perform a physical exam. Diagnostic tests may include:
- Electrocardiogram (ECG) – Records electrical signals of the heart to detect abnormal rhythms.
- Holter monitor – A portable device worn to record heart rhythm continuously for 24-48 hours.
- Event recorder – A small portable device used to record sporadic episodes of abnormal heart rhythms as they occur over weeks or months.
- Echocardiogram – An ultrasound of the heart used to evaluate the structure and function of the heart.
- Blood tests – To check for electrolyte imbalances, anemia, thyroid problems or cardiac enzymes indicating heart injury.
These tests help identify the type of tachycardia and guide appropriate treatment.
Treatments for tachycardia
Treatment depends on the underlying cause and type of tachycardia. Options may include:
- Treating underlying conditions – Correcting causes like anemia, dehydration, fever or hyperthyroidism.
- Medications – Drugs like beta-blockers, calcium channel blockers, or antiarrhythmic meds to control heart rate and rhythm.
- Electrical cardioversion – Applying a controlled electric shock to reset the heart rhythm back to normal.
- Ablation procedures – Using catheters to destroy small areas of heart tissue causing abnormal electrical signals.
- Implantable devices – Inserting a permanent pacemaker or defibrillator for serious arrhythmias.
- Surgery – In rare cases, invasive surgery may be done to remove or correct a problematic section of heart tissue.
Lifestyle changes like avoiding caffeine, alcohol, smoking, and stress reduction techniques may also help manage tachycardia episodes.
When is tachycardia an emergency?
Most cases of tachycardia are not emergencies. However, some types require prompt medical treatment:
- Ventricular tachycardia – A rapid heart rhythm originating in the ventricles puts a person at risk of sudden cardiac arrest.
- Supraventricular tachycardia with hemodynamic compromise – An extremely rapid heart rate that causes low blood pressure, chest pain, shortness of breath or loss of consciousness.
- Newly onset atrial fibrillation with rapid ventricular response – AFib with a dangerously fast and irregular heart rhythm requires urgent treatment to prevent complications.
These types of tachycardia are considered medical emergencies. Call 911 or emergency medical services if tachycardia is accompanied by:
- Chest pain
- Difficulty breathing
- Dizziness or fainting
- Rapid, racing heartbeat
Prompt emergency care is essential to stabilize the heart rhythm and prevent serious consequences.
Preventing tachycardia episodes
For people prone to tachycardia, some tips to help prevent episodes include:
- Avoiding triggers like caffeine, nicotine, recreational drugs, decongestants, and certain medications that can accelerate heart rate
- Staying well hydrated and maintaining optimal electrolyte balance
- Using prescribed medications to manage arrhythmias or control heart rate
- Practicing stress management and relaxation techniques
- Getting adequate sleep and rest
- Engaging in regular moderate exercise while avoiding overexertion
- Following up regularly with a cardiologist
Wearable heart rate monitoring devices can also help alert patients to increases in heart rate.
Brief episodes of tachycardia are common and often harmless. However, persistent or recurring tachycardia, episodes lasting more than a few minutes, or tachycardia with other symptoms often warrants medical evaluation. The risk of complications rises the longer tachycardia goes untreated. With proper diagnosis and management, most types of tachycardia can be successfully controlled and prevented from causing serious harm.