Heart arrhythmias

What is an arrhythmia?

Heart rhythm problems (arrhythmias) occur when the electrical impulses in your heart that coordinate your heartbeats don’t function properly, causing your heart to beat too fast, too slow or irregularly.

What may I feel if I have one of these rhythm disturbances?

Arrhythmias often cause symptoms, including palpitations. The term “palpitations” is a descriptive word used to describe the sensation of an abnormal pattern of heart beats. Common patterns include feelings of skipped or extra beats, fluttering, thumping, flip-flops and a racing heartbeat. However, not all palpitations are due to arrhythmias – sometimes palpitations are felt even when the heartbeat is normal, such as during a stressful or anxious occasion like public speaking. Many people who experience palpitations even on a very frequent basis, may have minimal or no heart rhythm disturbance.

How do I know if I have an arrhythmia?

When people complain of palpitations, the first step is to try to diagnose whether a significant arrhythmia is occurring. Your doctor will assess this by going through your symptoms in detail. These may include:

  • fluttering in your chest
  • racing heartbeat
  • chest pain
  • shortness of breath
  • lightheadedness
  • dizziness
  • fainting

Your doctor will also examine you and your heart and its rhythm. Often, further tests are needed to make a diagnosis. These tests also help determine whether there are any other problems with the heart (for example – a leaking valve). Different arrhythmias require differing treatments, and your doctor will be able to recommend the most appropriate therapy for your particular situation.

What causes arrhythmias?

Conditions that may lead to arrhythmias include -:
Problems that affect the structure or function of the heart. These include an abnormal heart valve or weakened heart muscle from a virus or other disease (cardiomyopathy)
An inadequate blood supply to the heart that can occur when the coronary arteries are narrowed or blocked
Scarring of the heart muscle that can develop with various diseases and after a heart attack
Environmental factors such as stimulant drugs, alcohol, intercurrent illness and sleep deprivation
Some non-cardiac health problems such as an overactive thyroid gland and severe lung disease

Are there different types of arrhythmia?

Arrhythmias are classified by where they originate (atria or ventricles) and by the speed of heart rate they cause. Tachycardia refers to a fast heartbeat — a heart rate greater than 100 beats a minute. Bradycardia refers to a slow heartbeat — less than 40-50 beats a minute. Not all tachycardias or bradycardias indicate arrhythmia though. For example, during exercise, it is normal to develop a tachycardia, while the heart often slows down to 30-40 beats a minute during sleep.

Some of the more common arrhythmias are listed below :

  • Ectopic (extra) beats. These are very common and can originate from the atria or ventricles. They usually cause symptoms of skipped or extra beats. They tend to last for moments at a time, but can recur many times over hours to days. They can also come in bursts or “storms”, lasting weeks at a time. Ectopic beats are generally harmless and are just a nuisance. They are occasionally treated, especially if they are causing troublesome symptoms or are extremely frequent (>10,000 per day).
  • Atrial fibrillation. Irregular and rapid contractions of the atria that cause an irregular heartbeat that is often too rapid. It is the most common “significant” arrhythmia. It can last for minutes to weeks, with many people remaining in atrial fibrillation permanently. There are multiple different causes and the condition generally requires some form of treatment. The most serious risk associated with atrial fibrillation is stroke. For those people at risk, blood-thinning medications (anticoagulants such as warfarin) are used long-term for stroke prevention.
  • Atrial flutter. Similar to atrial fibrillation, but the atria tend to contract in a rapid and regular (rather than irregular) pattern. Similar causes, risks and treatments as atrial fibrillation.
  • SVT. Supraventricular tachycardia is characterised by rapid, regular contractions originating from the atria. Often occurs in young people. Generally causes unpleasant symptoms including palpitations, shortness of breath and even fainting. Can be caused by specific heart conditions such as Wolff-Parkinson-White syndrome. Usually require treatment with drugs or with a procedure known as ablation (see below).
  • Ventricular tachycardia. An arrhythmia that arises from the ventricle and is often very rapid. It is usually occurs with a structural heart problem such as scarring following a heart attack. It is one of the most serious rhythm disturbances and is associated with significant risks including sudden death. Almost always requires treatment that may include a combination of drugs, implantation of a special pacemaker-like device called an implantable defibrillator and ablation.

How are arrhythmias diagnosed?

Tests will need to be performed to confirm a diagnosis and look for any possible underlying causes.
These may include:

  • Electrocardiogram (ECG): An ECG can positively confirm the diagnosis if the rhythm disturbance is actually occurring at the time of the recording. This test may not be helpful if the arrhythmia is intermittent.
  • 24-hour heart (Holter) monitor: This portable ECG device can be worn for a day to record your heart’s activity as you go about your routine. This may pick up intermittent arrhythmias.
  • Event monitor: This monitor is similar in concept to a Holter monitor, but can be applied for up to 1 week at a time. It therefore increases the chance of capturing an intermittent rhythm problem on and ECG recording.
  • Echocardiogram: An ultrasound test that looks specifically at the heart, its muscle, chambers and valves. It is an accurate test to determine whether there is any underlying heart problem. However, it does not show if there are any blockages or narrowings in the coronary arteries.
  • Stress test: This may be performed to bring on a rhythm disturbance if there is a particular association with exercise. It may also be used as a screening test for the presence of coronary artery disease.
  • Electrophysiology study: In this test, thin, flexible tubes (catheters) tipped with electrodes are threaded through your blood vessels to a variety of spots within your heart. The source and spread of the heart’s electrical impulses is mapped. The heart can also be stimulated to try to bring on an arrhythmia. If needed, ablation can be performed during the same procedure to treat the arrhythmia.
  • Thyroid function tests: A simple blood test to measure the activity of the thyroid gland.

What is the treatment for arrhythmias?

Treatment very much depends on the cause. If your doctor has diagnosed simple ectopic beats without any other heart problem, no treatment may be needed. Lifestyle changes, such as reducing caffeine intake, may all that is required.

For more serious arrhythmias, treatment approaches may include:

  • Mild anti-arrhythmic drugs. A number of drugs can be used that have a mild action and relatively few side effects. However, they also tend not to be as effective as some of the stronger anti-arrhythmics. These include digoxin (Lanoxin), beta blockers such as metoprolol (Betaloc, Metohexal), and atenolol (Tenormin, Tensig, Noten), calcium channel blockers such as verapamil (Isoptin, Veracaps) and diltiazem (Cardizem).
  • Stronger anti-arrhythmic drugs. More powerful anti-arrhythmic medications are sometimes used such as sotalol (Sotacor), amiodarone (Cordarone X, Aratac) and flecainide (Tambocor). Although often very effective, the main drawback of these agents is the increased risk of side effects. These drugs are usually reserved for the more serious arrhythmias, and your doctor will go into much more detail about their risks and benefits.
  • Ablation. This is a specialised invasive procedure where special tubes (catheters) are placed in your heart via a large vein in your groin. The catheters locate the trigger for the arrhythmia. A small area on the inside of the heart is then burnt by the application of radiofrequency energy to that area. Several different types of arrhythmias can be treated with ablation including SVT, atrial fibrillation, atrial flutter and ventricular tachycardia. Again, your doctor will discuss with you in much more detail whether you may be a candidate for this type of treatment.
  • Pacemaker. A pacemaker is a small device that is able to regulate and prevent slow heartbeats (bradycardia). It is implanted under the skin just below your collar bone. Pacemakers are used in people whose heart rate is too slow or at risk of slow heart rates in the future. They are also sometimes be used in conjunction with medicines to avoid the heart-slowing effect of many anti-arrhythmic drugs.
  • Implantable cardioverter defibrillator (ICD). This is another type of implanted device that can both act as a pacemaker and deliver an internal electric shock if the heart develops one of the life-threatening rapid arrhythmias such as ventricular tachycardia. It is a bit bigger than a pacemaker, but is still small enough to go under the collar bone. Your doctor will advise you if you are suitable candidate for one of these devices.
  • Heart surgery. A number of arrhythmias can be cured by open heart surgery but this is rarely needed now because of advances in catheter ablation techniques. Arrhythmia surgery is most commonly performed these days in conjunction with other heart surgery, such as treating atrial fibrillation at the time of a valve replacement operation.

Is there anything I can do with my diet and lifestyle that can help?

Your doctor may advise that in addition to other treatments, you may need to make lifestyle changes that will keep your heart as healthy as possible. These may include cutting back on caffeine and alcohol, increasing physical activity and quitting smoking. You might also be asked to find ways to reduce the amount of stress in your life.