Dr Kerwin answers some frequently asked questions

What is an arrhythmia?

An arrhythmia is an irregular heart beat, which may be experienced as a very fast beat or very slow beat or a skipped beat.

Is an arrhythmia a sign that a person has heart disease?

No. Many people who experience arrhythmias don’t have underlying heart disease.

What causes arrhythmias?

Often, it’s hard to pinpoint a clear cause of an arrhythmia. Heart disease may lead to arrhythmias. Other factors that may provoke them include: stress, caffeine, smoking, alcohol, diet pills, and cough and cold medicines.

Is an arrhythmia a serious medical condition?

In the vast majority of cases, the arrhythmia is nothing to worry about. These arrhythmias do not require the person to undergo examinations or treatments for the condition. In some people, the arrhythmia is linked to heart disease. In these cases, it is the heart disease, and not the arrhythmia, that poses the greatest risk to the patient. In the few cases where people present with serious symptoms, the arrhythmia itself is considered dangerous and requires medical to restore a normal heart rhythm. For example, some people have a very slow heartbeat, which is called bradycardia. This makes them feel lightheaded or weak. If the bradycardia is not treated, the heart may stop beating and the person may die.

Are arrhythmias common?

Arrhythmias are fairly common in middle-aged people. As you get older, you’re more likely to experience an arrhythmia.

What are the symptoms of an arrhythmia?

Symptoms may include fast heart beats, fluttering sensation in the chest, skipped heart beat, dizziness, shortness of breath, and even chest pain.

Sinus arrhythmia, which is a change in heart rate that can happen normally when you take a breath, is quite common. In most cases, however, this is completely harmless. There is no need to be anxious or to panic if you feel occasional heart flutters or heart racing. If these experiences occur frequently, you should see your doctor.

What are the different types of arrhythmias?

There are many types of arrhythmias. They are identified by where they occur in the heart, in the atria or ventricles, and by the type of heart rhythm they provoke.
When they originate in the atria, they are called atrial or supraventricular arrhythmias. Ventricular arrhythmias begin in the ventricles. Ventricular arrhythmias caused by heart disease are usually the most serious.

How does the doctor find out if I have an arrhythmia?

Sometimes the doctor can detect an arrhythmia by listening to the heart with a stethoscope. However, an electrocardiogram (ECG or EKG) is the most precise method for diagnosing an arrhythmia. The patient lies down, and disks are placed on the chest and connected by wires to an ECG machine. Electrical signals in the heart cause a pen to draw lines across a strip of graph paper. The doctor studies these lines to check for any changes in the normal rhythm. Though the patient experiences symptoms at other times, it is possible that during the ECG the arrhythmia does not occur. In such cases, other tests can be performed to find out whether an arrhythmia is causing the symptoms. Generally, the doctor will take a medical history and do a complete physical examination. Then one or more tests may be used to check for an arrhythmia and to decide whether it is caused by heart disease. These include: a stress test; Holter monitor; trans-telephonic monitoring; and an EP study.

What is a stress test?

A stress test is the common term for an exercise ECG, in which disks are attached to the patient's arms and legs as well as to the chest. While connected to the ECG machine, the patient exercises on a treadmill machine or stationary bicycle. This test reveals if exercising causes (or worsens) the arrhythmia and if there is evidence of inadequate blood flow to the heart (a condition known as ischemia). 

How does a Holter monitor work?

A Holter monitor performs a 24-hour ECG test. During the day, the patient wears a small, portable tape recorder that connects to the disks on his or her chest. Over time, this test reveals changes in rhythm or evidence of ischemia that was not detected during a resting or exercise ECG.

What is trans-telephonic monitoring?

The patient wears the tape recorder and disks over a period that can range from a few days to several weeks. When an arrhythmia occurs, the patient phones a monitoring station where the record is made. If the patient doesn’t have access to a phone when the arrhythmia occurs, he or she can activate the monitor's memory function. Later, the patient can transmit the recorded information from the memory to the monitoring station by phone. Trans-telephonic monitoring may be used to detect arrhythmias that occur only once every few days or weeks.

Electrophysiology (EP) study

An EP study involves the use of cardiac catheters, which are very thin, flexible tubes placed in a vein of an arm or leg and guided to the right atrium and ventricle. This procedure allows the doctor to determine the precise origin or location in the heart of an arrhythmia and how it responds to treatment.

How are arrhythmias treated?

Many arrhythmias require no treatment. Serious arrhythmias may be treated in several ways depending on the underlying causes of the arrhythmia. In some cases, heart disease is treated to control the arrhythmia. Or, the arrhythmia itself may be treated using one or more of the treatments described below:

There are various medications that can help restore normal heart rhythm and prevent further episodes of arrhythmia. However, they may not work as effectively as patients would like. Antiarrhythmic medications may also cause unwanted side effects, such as lethargy, and must be taken indefinitely – together, these two factors may add up to an unacceptable burden on otherwise healthy patients.

To quickly restore a heart to its normal rhythm, the doctor may apply an electrical shock to the chest wall. Called cardioversion, this treatment is most often used in emergency situations. After cardioversion, drugs are usually prescribed to prevent the arrhythmia from recurring.

Automatic implantable defibrillators 
An implantable cardioverter defibrillator (ICD) is a small electronic device placed inside the body where it monitors heart rhythm. When the ICD detects a potentially dangerous arrhythmia, it sends shocks to the heart to restore a normal heart rhythm. This is an effective way of dealing of dangerous arrhythmias such as ventricular tachycardia. Surgery is required to place the ICD inside the body. While an ICD is a form of treatment for tachycardias, it does not address the underlying problem that causes the arrhythmia.

Catheter ablation
Catheter ablation is a non-surgical minimally invasive procedure that involves ablating (destroying) parts of an abnormal conduction pathway in the heart that is causing an arrhythmia. During the procedure, an electrophysiologist threads a catheter, which is a long, flexible wire, through a vein into the heart. The tip of the ablation catheter then delivers energy to the tissue in the target location, which disables it. This interrupts electrical conduction along the abnormal pathway and effectively puts an end to the arrhythmia.