Bradycardia (Slow Heartbeat)

Bradycardia is a cardiac electrical condition where the heart beats more slowly than expected, typically when the resting heart rate falls below 60 beats per minute (bpm). While this may be normal in some individuals, especially athletes, or during sleeping hours, for others, it can signal an underlying health concern requiring a qualified electrophysiologist.

There are several types of bradycardia, including:

• Sinus bradycardia occurs when the heart’s natural pacemaker, the sinoatrial node, sends electrical signals slower than usual. This can be seen in healthy individuals and doesn’t necessarily indicate a problem.
• Sick sinus syndrome refers to sinoatrial node dysfunction, which leads to irregular rhythms that may alternate between too slow (bradycardia) and too fast (tachycardia).
• Atrioventricular (AV) block is where the electrical signals between the atria and ventricles are delayed or completely blocked. Heart blocks vary in severity, from first-degree, which involves small signal delays, to third-degree, where the signal is completely blocked, potentially leading to serious complications.

What Causes Bradycardia?

The causes of bradycardia are varied and may include age-related changes in the heart’s electrical system or heart disease, such as coronary artery disease. Certain medications, such as beta-blockers, calcium channel blockers, and digoxin, may slow the heart rate. Other causes include hypothyroidism (low thyroid function), electrolyte imbalances (particularly potassium and calcium), sleep apnea, and conditions that increase intracranial pressure, like brain injuries.

In addition, alcohol consumption can also have a significant effect. Alcohol, particularly in large quantities, can depress the heart’s electrical system, potentially worsening bradycardia. While stimulants like caffeine may temporarily increase heart rate, they can sometimes lead to a rebound effect, causing the heart rate to drop again. To avoid unnecessary fluctuations in heart rhythm, limit your intake of caffeinated beverages like coffee, tea, and energy drinks. Non-athlete individuals with symptomatic bradycardia should be cautious with strenuous exercise. Intense physical exertion can strain the heart, mainly if the patient has underlying conduction issues.

Cold weather can slow the heart rate by triggering the body’s natural response to preserve heat. Therefore, significant exposure to cold temperatures should be avoided.

Certain activities stimulating the vagus nerve can also slow the heart rate. These include straining during bowel movements, holding your breath for extended periods, or making sudden changes in posture, such as quickly standing up from a lying position. While stress is often associated with an increased heart rate, in some cases, it can trigger a vagal response, leading to episodes of bradycardia.

It’s also important to be cautious with over-the-counter (OTC) decongestants, such as those containing pseudoephedrine, which can cause irregular heart rhythms. Certain sleep aids or sedatives, including antihistamines, may also depress the heart rate.

Symptoms of Bradycardia

Symptoms of bradycardia can vary depending on its severity and cause. Some individuals may experience no symptoms, mainly if their bodies are accustomed to a slower heart rate. However, bradycardia can lead to fatigue, dizziness, lightheadedness, fainting (syncope), shortness of breath, chest pain, and cognitive issues like confusion or memory problems.

Diagnosing Bradycardia

Diagnosing bradycardia involves an electrocardiogram (ECG) to capture the heart’s electrical activity at a specific moment and identify abnormal rhythms. For intermittent or paroxysmal symptoms, a Holter monitor may be worn for 24 to 48 hours to track heart activity over time, while an event monitor might be used for longer if symptoms warrant. Blood tests can help identify underlying issues, such as thyroid dysfunction or electrolyte imbalances, and an echocardiogram may show the heart’s structure and function.

Treatment for Bradycardia

Treatment for bradycardia depends on its cause and symptoms. Sometimes, no treatment is necessary, especially if the slow heart rate doesn’t cause serious concerns. If medications are contributing to bradycardia, adjusting or discontinuing them might improve or resolve the problem. Treating underlying conditions, like hypothyroidism or correcting electrolyte balance, can help.

A pacemaker may be implanted to regulate the heart rate for persistent or symptomatic bradycardia, particularly in cases of heart block or sick sinus syndrome. This is typically the definitive treatment.

If bradycardia is accompanied by fainting, chest pain, severe shortness of breath, confusion, or sudden weakness, seek immediate medical attention. If bradycardia develops or worsens in someone with a known heart condition, consult a healthcare provider.

While a slow heartbeat can be expected in many individuals, particularly those who are physically fit, it may signal more serious health concerns in others. Early detection and appropriate management are key to ensuring optimal heart health. Contact our office to learn more.