The heart’s electrical system controls the heart’s rhythm or beating. An arrhythmia is a condition in which the electrical activity of the heart is irregular or is faster or slower than normal. The two main types of arrhythmias are:
- Bradycardia (a slow heart rate of less than 60 beats per minute)
- Tachycardia (a rapid heart rate of more than 100 beats per minute)
Some arrhythmias originate in the atria (the two upper chambers of the heart), while others originate in the ventricles (the two lower chambers of the heart). Despite the vast number of arrhythmias and related conditions, the Arrhythmia Program physician specialists at Froedtert & the Medical College of Wisconsin have the experience and expertise patients need to alleviate their problem.
Arrhythmias Originating in the Atria
- Atrial fibrillation (AF or A-fib) occurs when uncoordinated electrical signals emitted in the atria cause the atria to quiver instead of beat normally. Atrial fibrillation increases the risk of stroke and can lead to congestive heart failure. Learn more about the specialized expertise available through our Atrial Fibrillation program.
- Atrial flutter is another, more organized form of arrhythmia that occurs when rapidly fired signals cause the muscles in the atria to contract quickly, leading to a fast, unstable heartbeat.
- Paroxysmal atrial fibrillation (PAF), a form of A-fib in which symptoms occur intermittently. Treatments may include cryoballoon ablation.
- Paroxysmal supraventricular tachycardia (PSVT) involves both the ventricles and the atria. It is not life-threatening but may cause symptoms. A series of early beats in the atria speeds up the heart rate. An electrophysiology study is often used to make an accurate diagnosis. Possible treatment options for PSVT include medications or catheter ablation.
- Sick sinus syndrome (SSS) is a group of signs or symptoms that indicate that the heart’s sinoatrial (SA), or sinus node, is not working to as it should. The sinus node contains special "pacemaker" cells that generate the electrical signals that regulate the pace and rhythm of the heartbeat.
- Wolff-Parkinson-White (WPW) syndrome is a condition in which an abnormality in the pathway between the atria and ventricles causes electrical signals to arrive at the ventricles too soon and to be transmitted back to the atria. Rapid heart rates may develop.
Arrhythmias Originating in the Ventricles
- Ventricular tachycardia (VT) is a fast heart rate that starts in the ventricles. VT may or may not be life-threatening, but is a common cause of cardiac arrest and sudden death. VT may have many causes including cardiomyopathy (heart muscle disease), coronary artery disease, valvular disease, an isolated rhythm problem or a genetic condition such as Long Q-T syndrome. Treatment is more complex and may involve treating heart failure in addition to treating the arrhythmia.
- Ventricular fibrillation (VF) occurs when disordered electrical activity causes the ventricles to contract in a rapid, unsynchronized manner. Sudden death follows unless immediate medical help is provided.
Disorders Related to Arrhythmias
- Conduction disease is a heart rhythm condition that leads to fainting, or syncope. It happens when electrical signals from the atria fail to reach the ventricles, resulting in a slow heart beat (bradycardia) and inadequate flow of blood to the brain.
- Bundle branch block is a delay or obstruction in the transmission of the heart’s electrical impulses that impairs the heart’s ability to pump efficiently.
- Syncope is a temporary loss of consciousness (fainting) usually related to temporary insufficient blood flow to the brain.
- Premature beats (contractions) briefly interrupt the heart’s normal rhythm when the heart beats happen earlier than expected. Very common, premature beats cause one to feel the heart “skipped a beat” or did a “flip-flop.” Premature beats can originate anywhere in the heart
- Cardiomyopathy is any disease of the heart muscle that inhibits the heart’s ability to pump blood effectively. In some instances, the disruption leads to arrhythmias. There may be multiple causes of cardiomyopathy, including viral infections. Genetic cardiomyopathies include Long Q-T syndrome, arrhythmogenic right ventricular dysplasia (ARVD), hypertrophic cardiomyopathy (HCM) and Brugada Syndrome. A consultation with a cardiac geneticist and testing with cardiac MRI are valuable resources for patients with genetic cardiomyopathies, resources readily available through Froedtert & the Medical College of Wisconsin’s Heart and Vascular Center.