Bradycardia is a condition characterized by a heart rate slower than the normal range of 60 to 85 beats per minute. This condition may result in symptoms such as dizziness, weakness, fatigue, and shortness of breath, especially when the heart is unable to pump sufficient oxygen-rich blood to the body. However, some individuals with bradycardia may not present with any symptoms or complications. While a heart rate of 40 to 60 beats per minute during sleep or in healthy young adults and athletes is not usually a cause for concern, severe cases of bradycardia may require an artificial pacemaker to maintain an appropriate heart rate. The heart's electrical signals usually regulate it to beat in a steady rhythm, but sometimes these signals may result in abnormal heartbeats or arrhythmias. In the case of bradycardia, the electrical impulses slow down the time between heartbeats.
Insufficient oxygen supply to the brain and other organs due to bradycardia can lead to various symptoms, including chest pain, confusion or memory problems, dizziness or light-headedness, lethargy during physical activity, fatigue, fainting or syncope, and dyspnoea.
Bradycardia, a slower-than-normal heart rate, can be caused by several factors. These include age-related damage to heart tissues, heart disease or attack, congenital heart defects, myocarditis, heart surgery complications, hypothyroidism, chemical imbalances in the blood, obstructive sleep apnea, inflammatory diseases like rheumatic fever or lupus, and medications such as sedatives, opioids, and drugs used to treat heart rhythm disorders, high blood pressure, and some mental health disorders. Additionally, bradycardia can occur if the heart's electrical signals don't travel properly from the atria to the ventricles, which is called a heart block or atrioventricular (AV) block. Heart blocks are categorized into three groups: first-degree heart block, second-degree heart block, and third-degree (complete) heart block. First-degree heart block is the mildest form, second-degree heart block results in a slower and irregular heartbeat, and third-degree heart block occurs when none of the electrical signals from the atria reaches the ventricles, causing the ventricles to beat at a very slow rate. Bradycardia can cause symptoms such as chest pain, confusion or memory problems, dizziness or light-headedness, fatigue, fainting, dyspnea, and feeling lethargic during physical activity.
In order to diagnose bradycardia, a physical examination is typically conducted by the doctor, who listens to the heartbeat using a stethoscope. The doctor may also recommend certain tests to evaluate the heart rate and check for any underlying heart problems that could be causing bradycardia. Blood tests may be performed to detect other medical conditions that can lead to a slower heartbeat, such as an infection, an electrolyte imbalance, or an underactive thyroid (hypothyroidism).
The primary test used to diagnose bradycardia is an electrocardiogram (ECG or EKG). This test measures the electrical activity of the heart and can reveal whether the heartbeat is too slow, too fast, or absent altogether. While a simple EKG can identify the rhythm causing the slow heart rate, individuals may need to wear an ambulatory monitor to track their heart rate and rhythm over a longer period. The doctor will analyze the symptoms along with the data from the monitor to determine if the heart rhythm is the cause and if the heart rate is associated with the symptoms.
The treatment approach for bradycardia depends on the underlying cause and the severity of the symptoms. In cases where individuals don't experience any symptoms, treatment may not be necessary.
If the cause of bradycardia is related to an underactive thyroid, treating the thyroid condition may resolve the slow heart rate. In cases where no clear physical cause can be identified, the doctor may consider changing medications that might be contributing to the slow heart rhythm.
If the bradycardia symptoms are severe and other treatments have not been effective, a pacemaker may be recommended. Pacemakers are devices that monitor and control heart rhythm. They activate only when needed, sending electrical signals to the heart to increase the heartbeat rate when it becomes too slow.
Possible complications of bradycardia can arise in cases where the heart rate becomes too slow, leading to a lack of oxygen supply to the brain and other vital organs. These complications may include fainting, loss of consciousness, heart failure, and even sudden cardiac arrest or sudden death. It is important to monitor and treat bradycardia appropriately to prevent such serious complications.
Bradycardia may lead to various complications, such as frequent fainting, loss of consciousness or syncope, heart failure, and in severe cases, sudden cardiac arrest or even death.
Prognosis is generally good when the rhythm is promptly identified and corrected by a healthcare provider.