Supraventricular Tachycardia (SVT) and Beta Blockers

Introduction

Supraventricular tachycardia (SVT) is a rapid heart rhythm originating above the ventricles. It can cause symptoms like palpitations, dizziness, shortness of breath, and chest discomfort. Effective management depends on the type of SVT and the patient's overall health.

Role of Beta Blockers

Beta blockers are a class of medications that slow the heart rate and reduce its workload by blocking the effects of adrenaline on beta receptors. They are frequently used in the treatment of SVT, particularly for:

• Rate control: Slowing down the heart rate in certain types of SVT, such as atrial tachycardia.
• Preventing recurrences: Reducing the risk of future episodes of SVT.
• Symptom relief: Helping control symptoms like palpitations and anxiety associated with SVT.

When Are Beta Blockers Used?

Beta blockers are primarily used in:

1. AV Nodal Reentry Tachycardia (AVNRT) – Beta blockers help slow conduction through the AV node, preventing reentry circuits.
2. Atrial Tachycardia – They help control heart rate and reduce the frequency of episodes.
3. Post-Conversion Maintenance – After aborting an episode of SVT (e.g., with adenosine or cardioversion), beta blockers may prevent recurrence.

Commonly Used Beta Blockers for SVT

• Metoprolol (Selective beta-1 blocker, commonly used)
• Atenolol (Long-acting beta-1 blocker)
• Propranolol (Non-selective beta blocker, useful in stress-induced SVT)
• Esmolol (Short-acting, used in acute settings)

Considerations and Precautions

• Beta blockers should be avoided in patients with severe asthma or COPD, as they can worsen bronchospasms.
• Can cause bradycardia (slow heart rate) and low blood pressure.
• Patients with heart failure should receive beta blockers cautiously.
• Sudden withdrawal can lead to rebound tachycardia or hypertension – dose tapering is recommended.

Alternative Treatments

If beta blockers are not tolerated or ineffective, other treatment options include: - Calcium Channel Blockers (e.g., diltiazem, verapamil) - Antiarrhythmics (e.g., flecainide, amiodarone) - Catheter Ablation (definitive treatment for recurrent SVT)

Conclusion

Beta blockers are an effective treatment for managing SVT, particularly for rate control and symptom reduction. However, they require individualized selection based on the patient’s condition and comorbidities. Consultation with a cardiologist is essential to determine the most appropriate therapy.

Source recommendations

1. American College of Cardiology/American Heart Association Guidelines on Supraventricular Tachycardia

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
2. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2015/09/23/09/13/2015-ACC-AHA-HRS-Guideline-for-the-Management-of-Adult-Patients-With-SVT
3. https://www.ahajournals.org/doi/10.1161/cir.0000000000000311
4. https://www.acc.org/Guidelines
5. https://pubmed.ncbi.nlm.nih.gov/26399662/

2. European Society of Cardiology Guidelines on Supraventricular Tachycardia

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
2. https://academic.oup.com/eurheartj/article/41/5/655/5556821
3. https://pubmed.ncbi.nlm.nih.gov/31504425/
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2019/09/10/12/36/2019-ESC-Guidelines-for-Supraventricular-Tachycardia
5. https://www.ahajournals.org/doi/10.1161/cir.0000000000000311