|What Are The Different Arrhythmia Types?
The different types of arrhythmias are characterized by the effect they have on the speed of your heartbeat (whether they speed it up or slow it down) as well as which part of the heart they occur in (the atria or the ventricles). If the heart does not beat properly it cannot pump blood effectively around the body. When this happens it can cause organs in the body, including the brain and lungs, to fail or be damaged. While a temporary irregularity or occasional skipped heart beat due to excess coffee or strenuous exercise will not cause any problem, the longer the arrhythmia lasts, the more dangerous it is. Some arrhythmias tend to be more dangerous than others. Arrhythmias fall into 4 main categories: premature contractions, supraventricular arrhythmias (fast heartbeats), ventricular arrhythmias and bradyarrhythmias (slow heartbeats). Another type of arrhythmia is called a heart block. This is a partial or complete interruption of electrical impulses in the heart which causes very weak pumping action by the heart. It is one of the causes of heart failure.
Premature Contractions - Skipped Heartbeats
This is the most common type of arrhythmia. It is usually quite harmless and does not require treatment. Premature contractions do not normally cause symptoms but may feel like your heart has 'skipped a beat', something like a fluttering or thump in the chest. In fact your heart has not skipped a beat but in reality the beat has come sooner than normal. Then there is a pause before the next beat which becomes more forceful. It is this forceful beat that you feel. Premature contractions are more common in kids and teenagers. They may also be caused in adults who drink too much caffeine, smoke, over-exercise or take over the counter medications containing ephedrine or ephedra (causes of arrhythmias). Periods of emotional stress may also be a cause. Very occasionally a premature beat can be caused by injury or disease to the heart. If your doctor suspects this he will order heart disease tests.
Supraventricular Arrhythmias - Fast Heartbeats
If the heart beats too fast, this is known as a tachycardia. There are a few different types of supraventricular arrhythmias including atrial fibrillation (AF), atrial flutter, paroxysmal atrial tachycardia (PAT):
Atrial Fibrillation (AF) - Quivers
This is the most common type of serious arrhythmia (up to 10 percent of Americans over 65 have it). Atrial fibrillation (also called AF or AFib) is an irregular or quivering heartbeat and is one of the causes of stroke and other heart related problems (it is also a cause of heart failure). It is also referred to as quivering heart. Some patients describe their symptoms as a 'heart flip-flop, skipped heartbeat' or 'feels like my heart is banging against my chest'. Some might only experience occasional symptoms (such as heart palpitations, a general term for any change in heartbeat) which last anywhere between a few seconds to a few days before symptoms disappear again (paroxysmal atrial fibrillation). In others AF is persistent and episodes do not stop without drugs and treatment. Some people on the other hand experience no symptoms at all and the condition is only discovered during a routine health screening. What happens during AF? Normally the heart expands and relaxes to a regular beat. With AF, the upper chambers of the heart (atria) beat irregularly (quivering) so blood is not pumped forcibly out (diagram of heart). This causes blood to gather in the atria which can turn into a blood clot. If a clot travels from the heart and gets trapped in an artery supplying the brain it can cause a stroke (brain attack).
Atrial flutter is another common type of arrhythmia in which the atria beats too fast but regularly (AF is too fast but irregularly). Rapidly fired signals in the atria cause these speedy contractions so the heart does not pump as efficiently as it needs to. Flutters often occur as the consequence of a heart attack, lung surgery or heart bypass surgery. An episode might last a few seconds or a few hours and cause palpitations, chest pain, light-headedness and shortness of breath. For others it may persist until arrhythmia treatment is prescribed. If it persists with medications it can deteriorate into AF and surgery (cardiac ablation) may be required.
Paroxysmal Atrial Tachycardia (PAT) - Sudden Fast Heartbeats
PAT is where the heart beats very fast, beginning suddenly and ending just as suddenly. People describe it as feeling like a 'pounding heartbeat' and it is often accompanied by dizziness, light-headedness, palpitations and chest pain. It is not normally dangerous and is more common in younger people who are particularly anxious, physically fatigued; drink large amounts of coffee or alcohol and who smoke heavily. Treatment is usually recommended in the form of lifestyle changes such as eliminating stimulants like caffeine and smoking.
Ventricular Fibrillation (VF)
Highly lethal, ventricular fibrillation (VF or v-fib for short) occurs when disorganized electrical signals cause the ventricles in the heart to quiver rather than pump. As there is no pumping action, after a few minutes the heart ceases to function and the person dies of sudden cardiac arrest. This condition needs to be treated within a few minutes with an electric shock to the heart (automated external defibrillator, AED) to have any hope of saving the person's life. If a doctor suspects you may be of risk of VF he might ask you to wear a Holter monitor or event monitor to record your heart activity for a period of time (arrhythmia diagnosis). If the risk is confirmed medications can help control some rhythm disturbances although an implantable cardioverter defibrillator (ICD) may be recommended if you are particularly high risk.
Ventricular Tachycardia (VT)
Like PAT, ventricular tachycardia can be characterized by attacks of rapid heartbeat, dizziness and sometimes chest pain or fainting. Patients often describe feeling a dread that 'something bad is about to happen'. VT is however more dangerous than PAT in that it can degenerate into ventricular fibrillation (VF) within minutes and can be fatal. As a result it is considered a medical emergency and the goal of treatment is to stop the rapid heartbeat (sometimes with defibrillation) and then to prevent it from occurring again.
Bradycardia or 'Brady' is an arrhythmia where the heart beats slower than normal. A slow heart rate is strictly defined as 60 beats per minute (bpm). Medical problems do not however usually occur until heart rates fall below 40 bpm. Some people may have normally slow heart rates which are not considered dangerous; athletes in particular commonly have a bpm below 60. But in other people a slow heart rate may be due to a serious underlying condition. Certain drugs, particularly in the elderly, can cause bradycardia. Medications or temporary pacemakers can be used to temporarily speed up the heart beats again but often a permanent pacemaker is the only long-term solution. Call your doctor if you have the following symptoms of bradycardia:
1. Shortness of breath (associated with little activity)
3. Light headedness
4. Fainting or nearly fainting
5. Pulse less than 50
See also, other symptoms of arrhythmia.
What Is A Heart Block?
This is where the electrical signal between one part of the heart (atria) and the other part (ventricles) is not working properly. It usually occurs in people with scarring on the heart due to coronary heart disease or valvular heart disease (hereditary). Prior heart surgery may also cause scarring and certain medications such as some calcium-channel blockers and beta blockers drugs can worsen it. There are several degrees of heart block:
First-Degree Heart Block: This is where the PR interval (the amount of time it takes for an impulse to travel from the atria to the ventricle) is slower than 0.2 seconds. If the heart rate and rhythm is normal, there may still be nothing wrong with your heart, in fact many perfectly healthy athletes have first degree heart block. If you are taking certain medications such beta blockers or digitalis, this may be causing the problem.
Second-Degree Heart Block: Occurs when not all the electrical signals reach the ventricles from the atria. This results in dropped beats. You may experience no symptoms or have some dizziness. The condition is not considered serious.
Third-Degree or Complete Heart Block: No signals are passing from one side of the heart to the other. On an ECG test (electrocardiogram) the relationship between the P wave and the QRS wave is completely abnormal. Someone with third degree heart block can develop heart failure or sudden cardiac death so it is treated as a medical emergency. A temporary pacemaker may be used to keep the person alive until surgery can be scheduled.
What Is Long Q-T Syndrome?
Long Q-T syndrome (LQTS) is a rare and usually hereditary disorder which can occur in otherwise healthy people. It usually affects kids and teenagers. It means the heart is not recharging as well as it should at the end of a heartbeat. The main symptom is fainting or blacking out, usually during physical activity or when experiencing intense emotions (pain, panic, anger or fright). Studies show that people with LQTS usually have at least one episode of fainting by the age of 10. It can lead to an abnormally rapid heartbeat (a type of ventricular tachycardia called torsade des pointes) that causes the heart to pump less effectively. If the brain does not receive enough oxygen it causes a fainting spell. It the heart cannot return to a normal rhythm it may degenerate into a fatal ventricular fibrillation. Treatment for LQTS usually involves taking beta blockers although an ICD may be necessary to prevent ventricular fibrillation. People with LQTS may benefit from having a home defibrillator. It should also be noted that deafness can occur with one type of inherited LQTS.
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