Your heart is essentially a pump that functions by pushing the blood through its four chambers in a carefully controlled sequence of muscular contractions. This sequence is controlled by bundles of cells which control the electrical activity of the heart. When the sequence is disturbed, heart arrhythmias result.
Ectopic Heartbeat-When Your Heart Skips a Beat
One of the commonest and least serious heart arrhythmias is called ectopic atrial heartbeat-a small variation in an otherwise normal pulse. You may have a sensation of skipping a beat. Another extremely common ectopic heartbeat is ventricular premature complexes, or VPCs. Nearly two out of three adults have these during a 24-hour period. In most cases ectopic heartbeat is harmless unless there are other symptoms, in which case medications to control the heart rhythm may be prescribed. If you have ectopic heartbeat, try decreasing or avoiding alcohol, tobacco and caffeine.
Tachycardia-When the Heart Beats Too Fast
If you feel your heart race, you may be experiencing an attack of atrial tachycardia, which can last from minutes to as long as a day or two. Your heart rate may range from 140 to 240 beats per minute and you may have a feeling of intense anxiety. An attack of atrial tachycardia is not life-threatening, although repeated attacks may increase your risk of heart failure. Once your doctor has examined you and found no other heart problems, he or she may instruct you in techniques for treating this heart problem, such as breath-holding or mild pressure on the arteries of your neck. Medication and refraining from alcohol, tobacco and caffeine are also helpful.
Ventricular tachycardia, in which the ventricles of the heart contract too fast, occurs in the several days immediately after a heart attack.
Fibrillation-Rapid, Uncoordinated Contractions
In atrial fibrillation, the atrial chambers of the heart beat irregularly and ineffectively, so that the atria do not empty completely. As a result of decreased blood flow you may feel faint and lightheaded. Atrial fibrillation may have no apparent cause, or it may be a result of heart disease or excess thyroid hormone. Treatment consists of medication or, in some cases, an electrical stimulus called electrical cardioversion that restores normal rhythm.
Ventricular fibrillation is a medical emergency in which the contractions of the heart’s ventricles are so inefficient that the heart virtually stops pumping blood. There is immediate loss of consciousness and pulse. Death occurs within minutes unless there is emergency intervention. Ventricular fibrillation has been associated with coronary artery disease, alcohol and cocaine consumption and exercise. But often no cause is found. It is the leading cause of death in young and middle-aged men.
If your doctor suspects an arrhythmia, you should have an ECG-an electrocardiogram. If the arrhythmia is intermittent, you may be given a Holter monitor, a portable ECG machine that records your heart rate during your daily activities.
See your doctor if you experience palpitations, skipped beats, lightheadedness, chest discomfort or shortness of breath. These may be signs of arrhythmia or other heart conditions requiring immediate attention.