Key Points about sinus bradycardia
- Sinus bradycardia is a slow heart rate (typically under 60 beats per minute) caused by slow electrical signals from the sinus node.
- It can be normal in athletes or during sleep but may also signal an underlying heart condition if symptoms occur.
- Causes include heart disease, thyroid problems and medications like beta-blockers.
- Diagnosis involves an ECG, Holter monitor and blood tests.
- Treatment depends on the severity of symptoms and may include medication or a pacemaker, if necessary.
Common related conditions
Sinus bradycardia causes
Sinus bradycardia may be caused by:
- Heart conditions, like coronary artery disease, heart attacks or heart failure.
- An overactive vagus nerve, which naturally slows the heart rate.
- Hypothyroidism (underactive thyroid).
- Electrolyte imbalances, particularly if you have high potassium levels.
- Medications, like beta-blockers, calcium channel blockers or digoxin (which slow the heart rate).
Sinus bradycardia risk factors
The following factors may increase your risk for sinus bradycardia:
- Older age, as the heart’s conduction system can slow over time.
- A history of heart disease, including previous heart attacks or heart failure.
- Use of medications that affect heart rhythm, including beta-blockers and digitalis.
- Hormonal imbalances like hypothyroidism.
- Being an athlete or having high physical fitness, which naturally results in a lower heart rate.
Sinus bradycardia symptoms
Symptoms of sinus bradycardia include:
- Fatigue or general weakness.
- Dizziness or lightheadedness, especially when standing up.
- Shortness of breath or difficulty during physical activity.
- Fainting or near-fainting episodes (syncope).
- Chest discomfort in some cases, particularly with exercise or exertion.
Sinus bradycardia diagnosis
Doctors diagnose sinus bradycardia through:
- Electrocardiogram (ECG or EKG) to measure the heart rate and rhythm.
- Blood tests or blood panels to check for an electrolyte imbalance or any thyroid disorders.
- A Holter monitor to record heart activity over 24-48 hours, capturing any random episodes.
- A stress test to evaluate heart function under physical exertion.
Sinus Bradycardia Treatment
Treatment options for sinus bradycardia depend on its severity and underlying causes:
- No treatment may be needed if the condition is asymptomatic or due to physical fitness.
- Medications, such as thyroid hormone replacement for hypothyroidism, may be prescribed.
- In severe cases with symptoms, a pacemaker may be implanted to regulate the heart rate.
- Adjusting medications that may be causing the bradycardia can also be effective.
When to Seek Care
You should seek medical attention if you experience:
- Symptoms like dizziness, fainting or difficulty breathing.
- A sudden or unexplained decrease in heart rate, especially with chest pain or discomfort.
- Fatigue or weakness that interferes with daily activities or exercise.
- Any irregular heart rhythms or palpitations.