Bradycardia is a heart condition characterized by a slower-than-normal heart rate. In healthy adults, the heart typically beats between 60 and 100 times per minute at rest. When the heart rate drops below 60 bpm, bradycardia may be present. While in some cases this slower rhythm is normal—such as in athletes or during sleep—in other situations it may signal a health problem requiring medical evaluation.
In this article, we will explain what bradycardia is, its most common symptoms, main causes, diagnostic methods, and available treatment options. We will also address myths and curiosities about the condition, as well as recent scientific advances in this field.
What Is Bradycardia?
Bradycardia is a type of cardiac arrhythmia, meaning an alteration in the normal rhythm of the heart. The heart works like a pump that sends oxygenated blood throughout the body, and its rhythm is controlled by electrical impulses originating in the sinoatrial node (the heart’s natural pacemaker). When these impulses are slow, irregular, or blocked, the heart beats more slowly, which characterizes bradycardia.
It is important to note that bradycardia is not always dangerous. In some people—especially young individuals and well-trained athletes—a resting heart rate below 60 bpm can be normal and even beneficial. The problem arises when the heart cannot pump enough blood to meet the body’s needs.
Symptoms of Bradycardia
Bradycardia often causes no symptoms and may be discovered only during routine exams. When symptoms occur, they are usually related to reduced blood flow and oxygen delivery in the body. The main signs include:
Dizziness or lightheadedness
Excessive fatigue
General weakness
Shortness of breath (dyspnea)
Mental confusion or difficulty concentrating
Chest pain
Fainting or near-fainting (syncope)
In severe cases, bradycardia may lead to serious complications such as heart failure, complex arrhythmias, or even cardiac arrest.
Causes of Bradycardia
Bradycardia can arise from a wide range of factors, from benign to heart or systemic diseases. The main causes include:
Physiological
High-performance athletes
Deep sleep
Cardiac
Sick sinus syndrome (damage to the heart’s natural pacemaker)
Atrioventricular blocks (problems in electrical conduction between atria and ventricles)
Prior heart attack or structural heart changes
Systemic
Hypothyroidism
Sleep apnea
Electrolyte imbalances (such as excess potassium)
Medications
Beta-blockers
Digoxin
Antiarrhythmics
Other Factors
Natural aging of the cardiac conduction system
Infections affecting the heart (such as myocarditis)
Diagnosis of Bradycardia
Diagnosis begins with a clinical evaluation and patient history, followed by complementary tests. The most common include:
Electrocardiogram (ECG): identifies heart rate and possible electrical abnormalities
24-hour Holter monitor: continuously records heart activity over an entire day
Exercise stress test: evaluates heart response during physical activity
Blood tests: check for secondary causes such as hormonal or metabolic issues
In some cases, imaging exams like echocardiograms may be requested to investigate structural heart abnormalities.
Treatment of Bradycardia
Treatment depends on the underlying cause and severity of the condition. In cases where bradycardia causes no symptoms or risks, no treatment may be necessary. However, when the heart cannot adequately supply the body, some measures may be required:
Medication adjustment: discontinuing or changing drugs that may be causing bradycardia
Treatment of associated conditions: correction of hypothyroidism, sleep apnea, electrolyte disturbances, etc.
Pacemaker implantation: in severe cases, when the heart cannot maintain an adequate rhythm, implantation of a device that regulates the heartbeat is indicated
Prognosis
With proper treatment, most patients with bradycardia can lead a normal, active life. Pacemakers, for instance, are highly effective and significantly improve quality of life. Regular medical follow-up is essential to prevent complications.
Curiosities, Myths, and Scientific Advances About Bradycardia
❌ Myth: “All bradycardia is dangerous.”
In reality, in athletes or young healthy individuals, bradycardia may simply reflect good physical conditioning.💡 Curiosity: The resting heart rate of some marathon runners may be around 40 bpm without causing any harm.
🧪 Scientific Advances: Modern pacemakers are becoming smaller and more sophisticated. Some models are now implanted via catheter, without invasive surgery, and adapt automatically to the patient’s activity level.
These advances allow for less invasive treatment and a more comfortable life for patients who depend on the device.
Conclusion
Bradycardia is a condition that deserves attention but is not always a serious problem. Accurate diagnosis is crucial to distinguish when it represents a normal variation and when it requires medical intervention. Advances in treatment—especially pacemaker technology—are providing increasing safety and quality of life for patients.
