Atrial Fibrillation - In atrial fibrillation, the atrium (the upper chambers of the heart) are in a state of electrical chaos, causing them to quiver — sometimes more than 600 times per minute — without contracting. The ventricles (the lower chambers of the heart) do not receive regular impulses and contract out of rhythm, and the heartbeat becomes uncontrolled and irregular. It is the most common atrial arrhythmia, and 85 percent of people who experience it are older than 65 years.
Atrial fibrillation can cause a blood clot to form, which can enter the bloodstream and result in a stroke. Underlying heart disease or hypertension increases the risk of stroke from atrial fibrillation, as does age.
Premature Atrial Contraction (PAC or premature atrial impulses) - A common and benign arrhythmia, a PAC is a heartbeat that originates away from the sinus node, which sends electrical signals through the upper chamber. It typically occurs after the sinus node has initiated one heartbeat and before the next regular sinus discharge. A PAC can cause a feeling of a skipped heartbeat. Use of caffeine, tobacco, and/or alcohol, or stress can bring on PACs or increase their frequency.
Supraventricular Tachycardia (SVT) - Characterized by a rapid heart rate that ranges between 100 and 240 beats per minute, SVT usually begins and ends suddenly. SVT occurs when an electrical impulse “re-enters” the atrial muscles. A disorder that a person may have at birth, SVT is commonly caused by a variation in the electrical system of the heart. SVT often begins in childhood or adolescence and can be triggered by exercise, alcohol, or caffeine. SVT is rarely dangerous, but can cause a drop in blood pressure, causing lightheadedness or near-fainting episodes, and, rarely, fainting episodes.
Atrial flutter - Differentiated from atrial fibrillation by its coordinated, regular pattern, atrial flutter is a coordinated rapid beating of the atria. Most who experience atrial flutter are 60 years and older and have some heart disorder, such as heart valve problems or a thickening of the heart muscle. As with atrial fibrillation, atrial flutter increases the risk of stroke.
Sick Sinus Syndrome (SSS) - Common among older people, SSS is an improper firing of electrical impulses caused by disease or scarring in the sinus node, which sends electrical signals through the upper chamber. SSS normally causes the heart rate to slow, but sometimes it alternates between abnormally slow and fast. SSS is a progressive condition, with episodes increasing in frequency and duration
Sinus Tachycardia – With Sinus Tachycardia, the sinus node emits abnormally fast electrical signals, which increases the heart rate to between 100 beats per minute to 140 beats per minute at rest, and 200 beats per minute during exercise.
Sinus Bradycardia - Associated with impaired impulse generation in the sinus node, sinus bradycardia causes the heart rate to decrease to fewer than 60 beats per minute.
Wolff-Parkinson-White syndrome (WPW) - In WPW syndrome, an extra electrical pathway between the heart’s upper and lower chambers causes a rapid heartbeat