Introduction An arrhythmia is a disorder of the heartbeat that affects the rate or rhythm. An arrhythmia occurs when electrical impulses, which regulate heartbeats, is not functioning properly. This causes the heart to beat too fast (tachycardia), too slow (bradycardia), too early (premature contraction), irregular, or too erratically rapid (fibrillation).
Heart arrhythmias are very common and many are harmless. Nearly everyone will experience an abnormal heart rhythm at one time or another. It may feel like your heart is skipping, pounding, racing or fluttering. But some arrhythmias are problematic or serious. Some arrhythmia effect quality of life and some of them are life threatening or even fatal. Heart arrhythmia treatment can often control or eliminate the fast or irregular heartbeats. You may be able to reduce your arrhythmia risk by adopting a heart-healthy lifestyle. To understand arrhythmias, it helps to understand the heart's internal electrical system. The heart's electrical system controls the rate and rhythm of the heartbeat. With each heartbeat, an electrical signal spreads from the top of the heart to the bottom. As the signal travels, it causes the heart muscle to contract and pump blood. Each electrical signal begins in a group of cells called the sinus node or sinoatrial (SA) node.
The SA node is located in the wall of heart's upper right chamber, the right atrium. In a healthy adult heart at rest, the SA node fires off regular electrical signal at rate about 60 to 100 times a minute. From the SA node, the electrical signal travels through special pathways in the right and left atria (upper chambers). This causes the atria to contract and pump blood into the heart's two lower chambers, the ventricles. The electrical signal then moves down to a group of cells called the atrioventricular (AV) node, located between the atria and the ventricles. Here, the signal slows down just a little, allowing the ventricles time to finish filling with blood. The electrical signal then leaves the AV node and travels along a pathway called the bundle of His. This pathway divides into a right bundle branch and a left bundle branch. The signal goes down these branches to the ventricles, causing them to contract and pump blood to the lungs and the rest of the body. The ventricles then relax, and the heartbeat process starts all over again in the SA node. A new cycle begins. A problem with any part of this process can cause an arrhythmia. There are many types of arrhythmia. Most arrhythmias are harmless, but some are not. Even serious arrhythmias often can be successfully treated. Most people who have arrhythmias are able to live normal, healthy lives.
Supraventricular arrhythmia (arrhythmia originating from atria – upper chambers)
Premature atrial contractions (PACs).
Paroxysmal supraventricular tachycardia (PSVT).
Associate with accessory pathway
Associate with AV node only
Sinus node dysfunction
Ventricular arrhythmia (arrhythmia originating from ventricle – lower chambers)
Premature ventricular contractions (PVCs).
Ventricular tachycardia (V-tach).
Arrhythmia associate with specific condition
Long QT Syndrome
Arrhythmogenic right ventricular dysplasia (ARVD)
Premature atrial contractions. These are early extra beats that originate in the atria (upper chambers of the heart). They are harmless and do not require treatment.
Atrial fibrillation. Atrial fibrillation is a very common irregular and fast heart rhythm that causes the atria, the upper chambers of the heart, to become quivering. The ventricles, the lower chambers will usually beat fast unless there are controlled by medication. Atrial fibrillation can be terminated with direct current cardioversion. Radiofrequency ablation technique is more effective than medication.
Atrial flutter. This is an arrhythmia caused by one or more rapid circuits in the atrium. Atrial flutter is usually more organized and regular than atrial fibrillation. It often converts to atrial fibrillation.
Paroxysmal supraventricular tachycardia (PSVT). A rapid heart rate, usually with a regular rhythm, originating from above the ventricles. PSVT begins and ends suddenly. There are two main types: accessory path tachycardia and AV nodal reentrant tachycardia (see below).
Accessory pathway tachycardia. A rapid heart rate due to an extra abnormal pathway or connection between the atria and the ventricles. The impulses travel through the extra pathways as well as through the usual route in a circle causing the heart to beat fast.
AV nodal reentrant tachycardia. A rapid heart rate due to more than one pathway through the AV node. In many cases, like the accessory pathway tachycardia, it can be terminated using a simple maneuvers, such as breathing in and bearing down, and others performed by a trained medical professional. Some drugs can also stop this heart rhythm. As with other tachycardia, it can be treated effectively with radiofrequency ablation technique.
Premature ventricular contractions (PVCs). These are among the most common arrhythmias and occur in people with and without heart disease. This is the skipped heartbeat we all occasionally experience. In some people, it can be related to stress, too much caffeine or nicotine. But sometimes, PVCs can be caused by heart disease or electrolyte imbalance. People who have a lot of PVCs, and/or symptoms associated with them, should be evaluated by a heart doctor. However, in most people, PVCs are usually harmless and rarely need treatment.
Ventricular tachycardia (V-tach). A rapid heart rhythm originating from the lower chambers (ventricles) of the heart. The rapid rate prevents the heart from filling adequately with blood; therefore, less blood is able to pump through the body. This can be a serious arrhythmia, especially in people with heart disease, and may be associated with more symptoms. A heart doctor should evaluate this arrhythmia.
Ventricular fibrillation. An erratic, disorganized firing of impulses from the ventricles. The ventricles quiver and are unable to contract or pump blood to the body. This is a fatal arrhythmia and a medical emergency that must be treated with cardiopulmonary resuscitation (CPR) and defibrillation as soon as possible.
Long QT syndrome. The QT interval is the area on the electrocardiogram that represents the time it takes for the heart muscle to contract and then recover, or for the electrical impulse to fire impulses and then recharge. When the QT interval is longer than normal, it increases the risk for "torsade de pointes," a life-threatening form of ventricular tachycardia. Long QT syndrome is an inherited condition that can cause sudden death in young people. It can be treated with antiarrhythmic drugs, pacemaker, electrical cardioversion, defibrillation, implanted cardioverter /defibrillator, or ablation therapy. This condition is not common.
Brugada syndrome. The Brugada syndrome is a genetic disease that is the major cause of sudden cardiac death in young men without known underlying cardiac disease in south east asia such as Thailand and Laos. It has characteristic abnormal electrocardiographic (ECG) ST elevation in early precordial leads. It is named by the Spanish cardiologists Pedro Brugada and Josep Brugada.
Brady-arrhythmias. These are slow heart rhythms, which may arise from disease in the heart's electrical conduction system. Examples include sinus node dysfunction, (Atrioventricular) heart block and medicine side effect.
Sinus node dysfunction. A slow heart rhythm due to an abnormal (SA) sinus node. Significant sinus node dysfunction that causes symptoms is treated with a pacemaker.
Heart block (Atrioventricular). A delay or complete block of the electrical impulse as it travels from the sinus node to the ventricles. The level of the block or delay may occur in the AV node or HIS-Purkinje system. The heart may beat slowly. If serious, heart block is treated with a pacemaker.
What are the symptoms of arrhythmias? An arrhythmia can be silent and not cause any symptoms. A doctor can detect an irregular heartbeat during a physical exam by taking your pulse or through an electrocardiogram (ECG). When symptoms of an arrhythmia occur, they may include:
Palpitations (a feeling of skipped heart beats, fluttering or "flip-flops," or feeling that your heart is "running away").
How are arrhythmias treated? Treatment depends on the type and seriousness of your arrhythmia. Some people with arrhythmias require no treatment. For others, treatments can include medication, making lifestyle changes, and undergoing specific procedures.
Antiarrhythmic drugs. These drugs are used to suppress the arrhythmia, or to control heart rate
Anticoagulant or antiplatelet therapy. These drugs reduce the risk of blood clots and stroke. These include warfarin (a "blood thinner"), aspirin, Plavix (Clopidogrel). There are newer medicine such as Pradaxa (dabigatran), Xarelto (Rivaroxaban), Apixaban (Eliquis) which were approved recently for prevent stroke in patient with atrial fibrillation.
If the arrhythmia occurs more often with certain activities, it should be avoided.
For the smoker, smoking should be discontinued.
Limit alcohol consumption.
Limit or stop using caffeine. Some people are sensitive to caffeine and may notice more symptoms when using caffeine products (such as tea, coffee, soft drinks, and some over-the-counter medications).
Stay away from stimulants used in cough and cold medications. Some such medications contain ingredients that promote irregular heart rhythms. Read the label and ask your doctor or pharmacist what medication would be best for you.
What Is Electrical Cardioversion? If drugs are not able to control a persistent irregular heart rhythm (such as atrial fibrillation), cardioversion may be required. Electrical cardioversion is effective in other form of tachycardias. After administration of a short-acting anesthesia, a direct current electrical shock is delivered to your chest wall allows the normal rhythm to restart.
What is a pacemaker? A pacemaker is a device that sends small electrical impulses to the heart muscle to maintain a suitable heart rate. Pacemakers primarily prevent the heart from beating too slowly. The pacemaker has a pulse generator (which houses the battery and a tiny computer) and leads (wires) that send impulses from the pulse generator to the heart muscle. Newer pacemakers have many sophisticated features that are designed to help manage arrhythmias and optimize heart rate-related function as much as possible.
What is an implantable cardioverter-defibrillator (ICD)? An ICD is a sophisticated device used primarily to treat ventricular tachycardia and ventricular fibrillation, two life-threatening arrhythmia. The ICD constantly monitors the heart rhythm. When it detects a very fast, abnormal heart rhythm, it delivers energy to the heart muscle to cause the heart to beat in a normal rhythm again. What Is Catheter Ablation? During an ablation, high-frequency electrical energy is delivered through a catheter to a small area of tissue inside the heart that causes the abnormal heart rhythm. This energy "disconnects" the pathway of the abnormal rhythm. Ablation is used to treat most PSVTs, atrial flutter, atrial fibrillation, and some atrial and ventricular tachycardia. Ablation may be combined with other procedures to achieve optimal treatment. Bangkok Heart Hospital has highly specialized atrial fibrillation ablation service, head by international renown, Dr. Koonlawee Nademanee.
What Is Heart Surgery for arrhythmia? Heart surgery may be needed to treat the arrhythmia such as the Maze procedure to correct atrial fibrillation. During this procedure, a series (or "maze") of incisions are made in the right and left atria to confine the electrical impulses to defined pathways. Some people may require a pacemaker after this procedure. Heart surgery can treat some conditions that cause the arrhythmia.