What is Sinus Bradycardia?

Introduction

Sinus bradycardia is a condition where the heart beats slower than normal, typically defined as a heart rate of fewer than 60 beats per minute (bpm) in adults. This condition originates from the sinus node, which is the heart's natural pacemaker.

Causes

Sinus bradycardia can occur in healthy individuals, especially athletes, but it can also be associated with medical conditions, including: - Increased vagal tone (common in athletes or during sleep) - Medication effects (such as beta-blockers or calcium channel blockers) - Electrolyte imbalances (like high potassium levels) - Hypothyroidism - Heart diseases (such as sick sinus syndrome or myocardial infarction)

Symptoms

Many people with sinus bradycardia do not have symptoms, but when symptoms occur, they may include: - Fatigue - Dizziness or lightheadedness - Shortness of breath - Fainting (syncope) - Chest pain (in severe cases)

Diagnosis

A healthcare provider typically diagnoses sinus bradycardia through: - Electrocardiogram (ECG) – To check the heart's electrical activity. - Holter monitoring – To record the heart rate over 24 to 48 hours. - Blood tests – To check for metabolic conditions or medication effects.

Treatment

Treatment depends on the underlying cause: - No treatment needed – If sinus bradycardia occurs in a healthy person without symptoms. - Medication adjustments – If the cause is medication-related. - Treating underlying conditions – Such as managing hypothyroidism or electrolyte imbalances. - Pacemaker implantation – In severe cases where the heart rate is too slow to maintain adequate blood circulation.

Conclusion

Sinus bradycardia can be normal or indicate a medical condition. If you have symptoms, it is essential to seek medical attention for proper evaluation and treatment.

Source recommendations

1. American Heart Association Guidelines on Bradycardia

1. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate
2. https://cpr.heart.org/-/media/cpr-files/cpr-guidelines-files/algorithms/algorithmacls_bradycardia_200612.pdf
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000628
4. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/algorithms
5. https://pubmed.ncbi.nlm.nih.gov/30586772/

2. European Society of Cardiology Guidelines on Management of Bradycardia

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Cardiac-Pacing-and-Cardiac-Resynchronization-Therapy
2. https://academic.oup.com/eurheartj/article/39/21/1883/4939241
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines
4. https://academic.oup.com/eurheartj/article/42/36/3599/6358045
5. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000628