What are the implications of tachycardia (abnormally high heart rate) and cardioversion (electrical or medical conversion of an abnormal heart rhythm to a normal one)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 18, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Cardioversion should be considered for high heart rates, specifically for irregular rhythms like atrial fibrillation or atrial flutter, when they cause symptoms such as dizziness, chest pain, or shortness of breath, as it can restore normal heart rhythm and improve quality of life 1.

Key Points to Consider

  • A high heart rate, or tachycardia, occurs when the heart beats faster than normal, generally above 100 beats per minute, and may require cardioversion if it's causing symptoms or is dangerous.
  • Cardioversion is a procedure that restores normal heart rhythm using either medications (chemical cardioversion) or an electrical shock (electrical cardioversion).
  • Not all fast heart rates need cardioversion—it's typically used for irregular rhythms like atrial fibrillation or atrial flutter when they cause symptoms.
  • For electrical cardioversion, sedation is given before brief electrical shocks are delivered to the chest, and the procedure takes only minutes.
  • Chemical cardioversion uses medications like amiodarone, flecainide, or propafenone to restore normal rhythm and may be attempted before electrical cardioversion in stable patients.
  • Both methods carry risks, including blood clots, which is why blood thinners may be needed before the procedure if the arrhythmia has lasted more than 48 hours.

Important Considerations

  • The decision to use cardioversion should be based on the individual patient's symptoms, medical history, and the underlying cause of the high heart rate.
  • Cardioversion works by resetting the heart's electrical system, allowing the natural pacemaker (sinoatrial node) to regain control of the heart rhythm.
  • If a sustained rapid heart rate with symptoms is experienced, medical attention should be sought promptly rather than waiting to see if it resolves.
  • The most recent guidelines, such as those from 2011, should be consulted for the latest recommendations on cardioversion and management of high heart rates 1.

From the Research

High Heart Rates and Cardioversion

  • High heart rates can be a symptom of atrial fibrillation (AF), a type of irregular heartbeat that can increase the risk of stroke and other heart-related complications 2, 3, 4, 5, 6
  • Cardioversion is a medical procedure that uses electrical shocks or medication to restore a normal heart rhythm in people with AF 2, 3, 4, 5, 6

Types of Cardioversion

  • Electrical cardioversion: uses electrical shocks to restore a normal heart rhythm 2, 4, 6
  • Pharmacological cardioversion: uses medication, such as amiodarone, to restore a normal heart rhythm 3, 4, 5, 6

Amiodarone for Cardioversion

  • Amiodarone is a medication that can be used for pharmacological cardioversion of recent-onset AF 3, 4, 5, 6
  • Studies have shown that amiodarone can be effective in restoring a normal heart rhythm in people with AF, especially when used in combination with other treatments 2, 4, 6
  • Amiodarone can also be used to prevent recurrence of AF after cardioversion 6

Efficacy and Safety of Amiodarone

  • Studies have shown that amiodarone is generally safe and effective for use in cardioversion, with a low risk of adverse effects 3, 4, 5, 6
  • However, amiodarone can have potential side effects, such as liver damage and thyroid problems, and should be used under the guidance of a healthcare professional 3, 4, 5, 6

Comparison with Other Treatments

  • Studies have compared the efficacy and safety of amiodarone with other antiarrhythmic medications, such as class IC agents, and found that amiodarone can be effective in certain situations 3, 5
  • However, the choice of treatment for AF should be individualized and based on a person's specific medical history and needs 2, 3, 4, 5, 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pre- and post-treatment with amiodarone for elective electrical cardioversion of atrial fibrillation: a systematic review and meta-analysis.

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.