Bradycardia is an unusually slow heart rate with a frequency of less than 60 beats per minute (bpm). A normal heart rate is between 60 and 100 beats per minute. However, a bradycardia as low as 50 beats per minute may be normal in athletes and other physically active people. In these individuals, regular physical exercise improves the heart\u2019s ability to pump blood efficiently with fewer heartbeats, thereby meeting the body\u2019s needs. <\/p>\n\n
As mentioned in the section on arrhythmias in general, under normal conditions, the electrical impulse for each heartbeat originates in the heart\u2019s sinus node. It is the heart\u2019s natural pacemaker, located in the upper part of the right atrium. From the sinoatrial node, the electrical impulse \u201ctravels\u201d to the atrioventricular node (AVN), which is located between the atria<\/strong><\/a>. It is then transmitted through the bundle of His (a series of modified cardiac muscle fibers located between the ventricles<\/strong><\/a>) and from there the impulse enters the muscles of the ventricles<\/strong><\/a>. This causes them to contract, producing a heartbeat. <\/p>\n\n In other cases, bradycardia may be a form of cardiac arrhythmia, an abnormality of the heart rhythm. Cardiac arrhythmia may be caused by a problem in the sinoatrial node, or it may be related to a disturbance in the conduction through the AV node and the bundle of His. Bradycardia can also occur at toxic levels of certain medications, such as digoxin, and narcotics. In addition, bradycardia is sometimes caused by the side effects of certain medications, including propranolol (Inderal), atenolol (Tenormin), metoprolol (Lopresor), sotalol, verapamil (Isoptin), and diltiazem (Tildiem). Bradycardia also occurs in some people with certain medical conditions unrelated to the heart, such as: <\/p>\n\n Bradycardia can cause dizziness, weakness, and a tendency to faint. If bradycardia is caused by a disease, there will be additional symptoms specific to that disease. For example, people whose bradycardia is due to severe hypothyroidism<\/strong> <\/a>may also experience constipation, muscle cramps, weight gain, very dry skin, thin and dry hair, sensitivity to cold, and other symptoms associated with low levels of thyroid hormones. <\/p>\n\n Your doctor will ask you about your family history of heart disease, heart arrhythmias, and fainting. They will also review your current symptoms and personal medical history, including any medications you are taking that may cause bradycardia. <\/p>\n\n During the physical examination, your doctor will check your heart rate and pulse. To further evaluate your bradycardia, you will undergo an electrocardiogram (ECG)<\/a><\/strong>. However, some forms of bradycardia come and go, and an in-office ECG may appear normal. In this case, a Holter<\/strong> <\/a>rhythm monitor. The patient is fitted with a portable ECG (Holter) monitor, usually for 24 hours. If your symptoms are infrequent, you may wear it for a longer period of time. <\/p>\n\n Depending on the results of the clinical examination, additional tests may be necessary to rule out conditions that may have caused bradycardia. For example, if you have symptoms and physical signs of hypothyroidism<\/strong><\/a>, your doctor may order blood tests to measure levels of thyroid hormones and TSH (thyroid-stimulating hormone, a hormone produced by the pituitary gland). Blood tests for cholesterol and liver enzymes may also be ordered, as these are often elevated in people with hypothyroidism<\/strong><\/a>. <\/p>\n\n The duration of bradycardia depends on its cause. For example, normal bradycardia in a well-trained athlete will last as long as the athlete maintains their usual level of physical activity. Some forms of bradycardia resulting from cardiac arrhythmias can be treated with a permanent pacemaker. <\/p>\n\n There are general guidelines for preventing all forms of bradycardia. When bradycardia occurs as a side effect of medication, the problem can be prevented by either changing the medication or reducing the dose. <\/p>\n\n In most cases, bradycardia in healthy, well-trained athletes does not require treatment. In fact, in most people, bradycardia does not require treatment unless patients have symptoms that are clearly due to a slow heart rate. Conditions that cause bradycardia and require treatment include: <\/p>\n\n Call your doctor if your heart rate is less than 60 beats per minute.BRADYCARDIA AS AN ARRHYTHMIA<\/h4>\n\n
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SYMPTOMS<\/h4>\n\n
DIAGNOSIS<\/h4>\n\n
EXPECTED DURATION<\/h4>\n\n
PREVENTION <\/h4>\n\n
TREATMENT<\/h4>\n\n
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WHEN TO CALL A DOCTOR<\/h4>\n\n
FORECAST<\/h4>\n\n