Low Heart Rate (Bradycardia) Symptoms and Causes

Introduction

A low heart rate, or bradycardia, is when the heart beats fewer than 60 times per minute. While it can be normal in athletes or during sleep, in some cases, it may indicate an underlying health concern.

Symptoms of Bradycardia

Bradycardia can be asymptomatic or present with various symptoms, including:

• Fatigue – A slow heart rate may reduce oxygen supply to the body, leading to tiredness.
• Dizziness or lightheadedness – Insufficient blood flow to the brain can cause these symptoms.
• Fainting (syncope) – A very slow heart rate may momentarily affect consciousness.
• Shortness of breath – The heart may not pump enough blood to meet body demands.
• Chest pain – This may indicate a lack of oxygen to the heart muscle.
• Confusion or memory problems – Reduced blood flow can impair cognitive function.
• Exercise intolerance – Patients may feel weak or breathless with minimal effort.

Causes of Bradycardia

Several conditions can lead to a slow heart rate, including:

• Age-related changes – Natural degeneration of the heart’s electrical system in older adults.
• Heart disease – Conditions like heart attack, myocarditis, or heart failure can affect the heart’s rhythm.
• Hypothyroidism – Low levels of thyroid hormones slow metabolism, including heart rate.
• Electrolyte imbalances – Low potassium or calcium levels may affect cardiac function.
• Medications – Beta-blockers, calcium channel blockers, and digoxin can slow the heart.
• Sleep apnea – Disruptions in breathing during sleep may contribute to bradycardia.
• Neurological disorders – Issues such as autonomic dysfunction can impact heart rate control.

When to Seek Medical Help

If low heart rate symptoms are severe or interfering with daily life, it’s essential to seek medical attention. Emergency care is needed if experiencing:

• Repeated fainting episodes
• Severe dizziness or confusion
• Chest pain or difficulty breathing

A doctor may use an ECG, blood tests, and other diagnostic tools to determine the cause and recommend treatment, which may include medication adjustments, pacemaker implantation, or treating underlying conditions.

Source recommendations

1. American Heart Association Bradycardia Guidelines

1. https://cpr.heart.org/-/media/cpr-files/cpr-guidelines-files/algorithms/algorithmacls_bradycardia_200612.pdf
2. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate
3. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/algorithms
4. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000628
5. https://pubmed.ncbi.nlm.nih.gov/30412710/

2. European Society of Cardiology Guidelines on Bradyarrhythmias

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Cardiac-Pacing-and-Cardiac-Resynchronization-Therapy
2. https://academic.oup.com/eurheartj/article/42/35/3427/6358547
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines
4. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000628
5. https://academic.oup.com/eurheartj/article-abstract/42/35/3427/6358547