Heart Rhythm Disorders (cont.)
Benjamin Wedro, MD, FACEP, FAAEM
Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Daniel Lee Kulick, MD, FACC, FSCAI
Dr. Kulick received his undergraduate and medical degrees from the University of Southern California, School of Medicine. He performed his residency in internal medicine at the Harbor-University of California Los Angeles Medical Center and a fellowship in the section of cardiology at the Los Angeles County-University of Southern California Medical Center. He is board certified in Internal Medicine and Cardiology.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
- How does the heart work?
- Premature atrial contractions (PACs) and premature ventricular contractions (PVCs)
- Sinus tachycardia
- Sinus bradycardia
- Abnormal heart rhythms
- Tachycardia
- Ventricular fibrillation
- Ventricular flutter
- Paroxysmal supraventricular tachycardia (PSVT)
- Wolf-Parkinson-White Syndrome
- Atrial fibrillation
- Atrial Flutter
- Bradycardia
- Heart blocks
- When should I seek medical care?
- How are heart rhythm disorders diagnosed?
- What is the treatment for heart rhythm disorders?
- Can heart rhythm disorders be prevented?
- Find a local Cardiologist in your town
Atrial Fibrillation (A Fib)
Atrial fibrillation occurs when the atrium has lost the ability to beat in a coordinated fashion. Instead of the SA node generating a single electrical signal, numerous areas of the atrium become irritated and produce electrical impulses. This causes the atrium to jiggle like a bowl of Jell-O instead of beating. The AV node sees all the electrical signals, but because there are so many, and because they are so erratic, only some of the hundreds of signals per minute are passed through to the ventricle. The ventricles then fire irregularly and often very quickly.
As in PSVT, the symptoms may include palpitations, lightheadedness, and shortness of breath. The cause of atrial fibrillation, however, may be more significant, since it may be due to aging of the conducting system of the heart and there may be associated atherosclerotic heart disease. Therefore, atrial fibrillation with rapid ventricular response associated with chest pain or evidence of pulmonary edema (pulmonary=lung +edema=fluid) may need emergent cardioversion (a procedure that uses electricity to shock the heart back into a normal rhythm) or intravenous medications to control the heart rate.
The long term significant complication of atrial fibrillation is the formation of blood clots along the inside of the heart wall. These clots may break off and travel to different organs in the body (embolize), blocking blood vessels and causing the affected organs to malfunction because of the loss of blood supply. A common complication is a clot traveling to the brain, resulting in a stroke.
The treatment of atrial fibrillation depends upon many factors including how long it has been present, what symptoms it causes, and the underlying health of the individual. There is debate as to whether it is important to convert atrial fibrillation to a regular sinus rhythm or whether it is adequate to just keep the heart rate under control.
Atrial fibrillation is a safe rhythm and not life threatening as long as the rate is controlled. Medications are used to slow the electrical impulses through the AV node, so that the ventricles do not try to capture each signal being produced. The reason to return people to a regular rhythm has to do with cardiac output. In atrial fibrillation, the atrium does not beat and pump blood to the ventricle. Instead blood flows into the ventricle by gravity alone. This lack of atrial kick can decrease the heart's efficiency and cardiac output by 10%-15 %.
Anticoagulation with warfarin (Coumadin) may be recommended for those patients with atrial fibrillation. Depending upon the underlying health of the individual and the risk of forming blood clots, aspirin may be used to prevent clot formation.
If atrial fibrillation is poorly tolerated due to symptomatic palpitations or symptoms of reduced cardiac output, or if there are concerns with lifelong Coumadin therapy, more definitive therapy may include specific medications, electrical cardioversion, or catheter based ablation (sometimes with an adjunctive pacemaker inserted). Atrial fibrillation is a common condition, with many implications, and the best plan for each patient should be discussed at length with one's physician.
Next: Atrial Flutter
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