Arrhythmias Must Reads
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- Weighing the Benefits and Risks of Alcohol
- Anatomy and Function of the Heart's Electrical System
- Keep Your Heart Muscle Strong
An arrhythmia (also referred to as dysrhythmia) is an abnormal rhythm of the heart that can cause the heart to pump less effectively.
Arrhythmias can cause problems by not allowing the ventricles (lower chambers) to fill with an adequate amount of blood because the electrical signal is causing the heart to pump too quickly. Arrhythmias also can prevent a sufficient amount of blood from being pumped out to the body because the electrical signal is causing the heart to pump too slowly or too irregularly.
When the heart doesn't pump blood effectively, the body's organs can't work properly and may shut down or be damaged.
The heart is, in the simplest terms, a pump made up of muscle tissue. Like all pumps, the heart requires a source of energy in order to function. The heart's pumping action comes from a built-in electrical conduction system.
In order for you to have a healthy, regular heartbeat--about 60 to 100 beats a minute--the heart's four chambers must work in harmony with one another. A heartbeat is produced when an electrical signal travels through these chambers. Any dysfunction in this signal can make the heart beat too quickly, too slowly, or at an uneven rate, causing an arrhythmia.
There are several types of arrhythmia:
Bradycardia: A too-slow heart rate of less than 60 beats per minute (BPM)
Tachycardia: A too-fast heart rate of more than 100 BPM
Fibrillation: The heart quivers but doesn't produce the coordinated pumping action needed to force blood through the heart and out into the body
Premature contraction: An early beat that disrupts the heart's rhythm
The cause is often unclear, but it could be related to factors such as heart disease, stress, caffeine, tobacco, alcohol, or cough and cold medicines that contain decongestants.
Tests and Procedures
There are several ways to diagnose arrhythmias. The standard tool is an electrocardiogram (ECG), which measures the electrical activity of the heart. Some variations include:
Resting ECG: Small, sticky patches called electrodes are attached to the patient's body and connected to the ECG machine by wires. The machine records the heart's electrical activity for a minute or so.
Signal-average ECG: The heart's electrical activity is recorded in the same manner as a resting ECG but for 15 to 20 minutes.
Exercise ECG, or stress test: The patient uses a treadmill or stationary bike while the ECG is recorded.
Holter monitor: This ECG recording is done over a period of 24 or more hours. Electrodes are attached to the patient's chest and connected to a small portable ECG recorder. During the procedure, the patient goes about his or her usual daily activities (except for showering, swimming, or anything that would cause an excessive amount of sweating, which could cause the electrodes to become loose). There are two types of Holter monitoring: continuous recording, in which the ECG is recorded continuously during the entire testing period, and event monitoring, in which the patient starts the ECG recording when symptoms are felt.
Another diagnostic option is electrophysiologic studies, in which a small, hollow tube called a catheter is inserted through the groin or neck into the heart. This allows the doctor to find the site of the arrhythmia's origin.
Arrhythmias may not cause any problems, so treatment isn't always needed. When necessary, your doctor chooses a treatment based on the type of arrhythmia, the severity of symptoms, and the presence of other conditions such as diabetes or heart failure.