Other rhythm problems
Rhythm problems can arise from the atria (collecting chambers) ventricles (pumping chambers) or the junction between them
Arrhythmias that originate in the heart’s upper chambers (atria)
Atrial Flutter (AFL)
Atrial flutter is similar to AF, characterized by a rapid heartbeat. Instead of rapid disorganized signals in the atria, however, AFL is caused by a single electrical wave that circulates very rapidly in the atrium (usually the right atrium), about 300 times a minute, leading to a very fast, steady heartbeat. Treatment can be curative with an invasive treatment.
Back to the top
Sick Sinus Syndrome (SSS)
Also called “sinus node dysfunction,” SSS is not a specific disease, but a group of signs or symptoms that indicate the heart’s natural electrical pacemaker, the sinoatrial node, is not functioning properly. In SSS, the heart rate may be abnormally slow at rest (bradycardia), or it may fail to speed up with activity or in response to adrenaline (chronotropic incompetence). If symptoms develop from SSS, or if the heartbeat is extremely slow even without symptoms, a permanent pacemaker is the primary treatment.
Back to the top
Sinus Tachycardia
A harmless rhythm, sinus tachycardia is a normal increase in heart rate that happens with fever, excitement and exercise. It rarely requires treatment aside from treating the underlying problem, such as anemia, infection, or hyperthyroidism. Rarely, the sinus node can cause the heart to beat faster than it should without any underlying cause. If symptoms result, the condition is known as “inappropriate sinus tachycardia,” and some treatment options are available.
Back to the top
Supraventricular Tachycardia (SVT)
This term describes several other types of fast heart rhythms that are not typically dangerous, but can cause symptoms of palpitations, fatigue, or shortness of breath. They typically start suddenly and stop suddenly, and may last for minutes or hours, with a rapid but steady pulse during the episode. The fast rhythm is usually caused by either an irritable spot that fires rapidly (atrial tachycardia, or AT), or by an electrical “short circuit” that involves an extra electrical connection between the top and bottom chambers of the heart (atrioventricular node reentry, AVNRT, or atrioventricular reentry with an accessory pathway, AVRT). Treatment options include medications or a catheter ablation procedure.
Back to the top
Arrhythmias that originate in the heart’s lower chambers, the ventricles
Back to the top
Ventricular Tachycardia (VT)
Characterized by a very fast heart rate, VT usually is seen in the setting of other serious heart disease, and may be life-threatening. Occasionally, it occurs in people with normal hearts. If it does not stop on its own, VT usually requires prompt treatment with either medication or an electrical jolt to the heart (electrical cardioversion). Further treatment of VT may involve antiarrhythmic medications, a catheter ablation procedure, or rarely surgery. Often, people with VT and heart disease are protected by implantation of a defibrillator (ICD). Because VT may lead to ventricular fibrillation (VF - next item), it is considered a serious condition that warrants aggressive monitoring and treatment.
Back to the top
Ventricular Fibrillation (VF)
Sudden cardiac arrest (SCA), caused by ventricular fibrillation, poses the greatest threat of all arrhythmias, and accounts for half of all cardiac deaths. In VF, the heartbeat is rapid and chaotic, which prevents the lower heart chambers, or ventricles, from pumping blood to the brain or body. During VF, the blood pressure falls to zero, and the person falls unconscious. A prompt, life-saving shock (defibrillation) must be delivered to the heart to restore a normal rhythm. Sometimes, VF can happen during a heart attack (myocardial infarction), because the heart muscle is irritated by the sudden blockage of an artery. VF can also happen at other times, and be caused by previous heart damage or an inherited (genetic) heart condition. It is important to realize that VF is an electrical disorder of the heart (not the same thing as a “heart attack”) and may or may not be related to a problem with clogged arteries that supply the heart with blood.
VF is sudden and happens without any warning. , It stops all heart functioning. The lack of blood and oxygen throughout the body, and especially to the brain, is deadly within a few minutes if not treated promptly with defibrillation. Although CPR can provide temporary benefit, the only truly effective treatment for VF is defibrillation, which relies onpaddles or electrodes to "shock" the heart back to normal rhythm. Without treatment, loss of consciousness comes in seconds, and death is inevitable within minutes.
Other
Back to the top
Premature Contractions
Extra, early, or "skipped" beats are the most frequent cause of irregular heart rhythms. These early, extra beats are weak and may not be felt in the chest or in the pulse at the wrist, which is why symptoms are frequently described as “skipped” beats. Extra beats can come from either the upper chambers (premature atrial complexes, PACs), or the lower chambers (premature ventricular complexes, PVCs) of the heart.
Back to the top
Long QT Syndrome (LQTS)
Long QT Syndrome is a disorder of the electrical system in which the heart cells take longer than normal to recover electrically after each heartbeat. It can be inherited, acquired after taking certain medications, or caused by a combination of heredity and medications. People with LQTS may be susceptible to ventricular fibrillation.
Back to the top
Heart Block
When some or all of the electrical impulses from the upper chambers of the heart are not properly transmitted to the lower chambers, the condition is known as “Heart Block”.
ECG rhythm strip showing an irregular heart beat- atrial fibrillation.
Different types of heart block may require different treatments, depending on exactly which part of the conduction system is faulty. If the bottom chambers beat too slowly, symptoms such as fatigue, lightheadedness, or fainting could develop. If the type of heart block is dangerous, or if symptoms result, a permanent pacemaker is the primary treatment.