What is Arrhythmia?
Arrhythmia is an abnormal rhythm of the heart. The contraction of the heart muscle creates your heartbeat. That contraction is triggered by an electrical signal in the upper chambers, or atria, of the heart. The atria contract, pumping blood into the lower chambers, or ventricles; then the ventricles pump blood/oxygen into the body and lungs. Electricity flowing through the heart causes the contractions; every electric impulse causes your heart to beat.
A problem anywhere along the electric pathway of the heart can cause an arrhythmia, or heart rhythm disturbance. It can cause your heart to beat too slowly – fewer than 60 beats/minute, known as bradycardia – or it can cause your heart to beat too fast – more than 100 beats/minute, known as tachycardia – or it can cause your heart to beat irregularly or chaotically.
Arrhythmias can happen in people with healthy hearts, but having some other sort of heart disease can raise your likelihood of having arrhythmia.
What are the types of Arrhythmia?
There are two main categories of arrhythmias: those that begin in the atria and those that begin in the ventricles.
Supraventricular arrhythmias (begin in the atria, or upper chambers)
- Atrial fibrillation [A-fib] – A-fib is a common arrhythmia, affecting over two million Americans. With A-fib, the heartbeat is irregular and fast, but is not life-threatening. A-fib can, however, lead to other rhythm disturbances, chronic fatigue or heart failure, and the risk of stroke is five times higher in people with A-fib.
- Atrial flutter – Like A-fib, atrial flutter is characterized by a rapid heartbeat. But unlike A-fib, rather than being caused by many disorganized signals, atrial flutter is caused by a single electrical wave circulating extremely quickly through the heart, leading to a very fast, steady heartbeat.
- Sick Sinus Syndrome [SSS] – SSS is a group of symptoms indicating the heart’s natural electrical “trigger” – the sinoatrial node, where the electrical signal begins – is not working properly. With SSS, the heartbeat can switch back and forth between too slow and too fast.
- Sinus tachycardia – Sinus tachycardia is a normal, harmless elevation in heart rate due to excitement, exercise or fever. It rarely requires treatment.
Ventricular arrhythmias (begin in the ventricles, or lower chambers) - Ventricular tachycardia [VT] – VT involves an extremely fast heart rate, typically within the context of other serious heart disease, though it occasionally happens in people with healthy hearts. VT typically requires prompt treatment and aggressive monitoring, as it can lead to ventricular fibrillation (see next item).
- Ventricular fibrillation [VF] – VF happens suddenly and without warning, and it stops all heart function. VT causes sudden cardiac death, also known as cardiac arrest, which accounts for half of all cardiac deaths. With VF, the heartbeat is rapid and chaotic, causing the ventricles to spasm, so they can no longer pump the blood/oxygen the body requires. Sometimes, a heart attack can lead to VF. The only effective treatment for VF is defibrillation, and it must happen quickly in order to save the patient’s life.
- Long QT Syndrome – Long QT Syndrome, an electrical system disorder, can be caused by genetics, medications or a combination of both. People with Long QT Syndrome are at a higher risk of ventricular arrhythmias.
Other arrhythmias - Premature contractions – These early, extra or “skipped” heartbeats are the most frequent cause of irregular rhythms. They can happen in the upper chambers [premature atrial contractions/PACs] or the lower chambers [premature ventricular contractions/PVCs] of the heart.
- Heart block – Heart block happens when the electrical signals created in the upper chambers don’t reach the lower chambers, causing the heart to beat too slowly.
- Syncope – Fainting, almost fainting, or feeling dizzy or lightheaded, can be caused by serious heart rhythm disorders and should be evaluated thoroughly.
What causes Arrhythmia?
Many conditions, activities and substances can potentially cause or lead to arrhythmia, including:
- genetics – being born with a heart abnormality
- heart disease
- changes in the heart muscle, or cardiomyopathy
- valve disorders
- injury or scarring due to heart attack
- healing process following heart surgery
- high blood pressure
- diabetes
- obesity
- hyperthyroidism
- electrolyte imbalances in the blood (such as sodium or potassium)
- obstructive sleep apnea
- stress
- excessive caffeine or alcohol intake
- smoking
- drug abuse
- dietary supplements
- over-the-counter medications (such as cough/cold remedies)
- prescription drugs, including some medications commonly prescribed for arrhythmias, heart disease and high blood pressure
- environmental/workplace exposures (such as industrial-plant pollution, automobile emissions, cigarette smoke, propane gas or paint thinners)
What are signs/symptoms of Arrhythmia?
Some arrhythmias are “silent,” causing no symptoms, while other cause bothersome symptoms that may be brief, long-lasting, or sudden and intense. Symptoms associated with arrhythmia can include:
- palpitations, or skipping a beat
- fluttering feeling in chest or neck
- racing heart sensation
- fatigue
- weakness
- dizziness or lightheadedness
- fainting or almost fainting
- shortness of breath
- chest pain
- suddenly rapid, chaotic heartbeat