Heart Rhythm Disorders
(Abnormal Heart Rhythms)

Heart Disease (Coronary Artery Disease) Slideshow

Medical Author: Benjamin C. Wedro, MD, FAAEM
Medical Editors: Daniel Kulick, MD, FACC, FSCAI, and Melissa Conrad Stöppler, MD

• 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?
• Patient Discussions: Heart Rhythm Disorders: What Type of Disorder

Featured heart rhythm disorders patient discussions on disorder you have "I have PSVT. The palpitations are uncomfortable and somewhat frightening even though I know they aren't life threatening. Sometimes, I also feel very cold and I can't seem to get warm. All the palpitations are made worse if I drink a caffeinated drink like tea or Diet Coke so I try to avoid them. " "I have had irregular heartbeats from time to time since I was young. I am now 30, and recently, I had an episode of irregular heartbeats for more than 14 hours. My pulse rate was 180 beats, and the doctor said I have ventricular tachycardia. He suggested I have an ablation done." "I have been diagnosed with atrial fibrillation as a consequence of stenosis of the mitral valve following aortic valve replacement surgery in September of 2000. " Read All Comments on Heart Rhythm Disorders » Top Searched Heart Rhythm Disorders Terms: types, antibiotics, paroxysmal supraventricular tachycardia (PSVT), what is an abnormal heart rhythm, palpitations, ecg, atrial fibrillation, ventricular tachycardia, supraventricular tachycardia, ventricular fibrillation, atrial flutter, sinus bradycardia, sinus tachycardia Patient Discussions are not a substitute for professional medical advice, or treatment. See the disclaimer at the bottom of the comments page.

How does the heart work?

The heart is a two stage electric pump whose job it is to circulate blood through the body. The pump is dependent on the electric current that the cells of the heart generate to have a coordinated squeeze so that the pump can pump.

The heart has four chambers, the right and left atria (singular= atrium) and the right and left ventricles. The right side of the heart pumps blood to the lungs while the left side pumps it to the rest of the body.

Blood from the body is collected in the right atrium and is pushed into the right ventricle with a small beat of the upper chamber of the heart. The right ventricle pumps the blood to the lungs to pick up oxygen, and the oxygenated blood from the lungs returns to the left atrium, where the small atrial beat pushes it to the left ventricle. The left ventricle is much thicker than the right because it needs to be strong enough to send blood to the entire body.

There are special cells in the right atrium called the sino-atrial node (SA node) that generate the first electrical impulse, allowing the heart to beat in a coordinated way. The SA node is considered the "natural pacemaker" of the heart. This pacemaker function begins the electrical impulse which follows pathways in the atrial walls, almost like wiring, to a junction box between the atrium and ventricle called the atrio-ventricular node (AV node). This electric signal causes muscle cells in both atria to contract all at once. At the AV node, the electric signal waits for a very short time, usually one to two tenths of a second, to allow blood to leave the atria and fill up the ventricles. The signal then passes through electric bundles in the ventricle walls to allow these chambers to contract, again in a coordinated way, and pump blood to the body.

The SA node generates an electric beat about 60-80 times a minute, and each should result in a heart beat. That beat can be felt as an external pulse. After a heart beat, the muscle cells of the heart need a split second to get ready to beat again, and the electrical system allows a pause for this to happen.

The heart and its electrical activity depend upon a relatively narrow normal state for it to work. Fortunately, the body tends to protect the heart as best as it can. Still, rhythm disturbances are frequent. Some disturbances are normal physiologic responses, but some are potentially life threatening.

Every cell in the heart can act as a pacemaker. The SA node has an intrinsic heart beat generation rate of 60-80. The AV node has a rate of about 40, and the ventricles themselves can generate beats at a rate of about 20 and may kick in if the cells of the upper chamber fail or if the electrical signals to the ventricle are blocked.

Heart Rhythm Disorders: What Type of Disorder

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