Arrhythmia

A change in your heartbeat - whether it seems to skip a beat or it starts to beat faster or slower - can be very scary. This type of change, called an arrhythmia (or dysrhythmia), is fairly common, especially as we get older.

An arrhythmia can be caused by many factors, including:

• heart disease
• stress
• caffeine, tobacco or alcohol use
• diet pills
• certain cough or cold medicines

Sometimes there is no known cause for an arrhythmia. Although the occurrence of an arrhythmia does not necessarily indicate an underlying heart condition, you should see a doctor if you experience an arrhythmia often, or if you have symptoms such as a rapid heartbeat, shortness of breath or dizziness.

Why arrhythmias occur

The heart is a pump divided into four chambers: two atria on the top and two ventricles on the bottom.

A normal heartbeat starts in the right atrium, where a group of cells called the sinus node, or natural pacemaker, sends an electrical signal. The signal then spreads through the atria and to the atrioventricular (AV) node. From there, the signal goes to the ventricles.

However, sometimes a heartbeat starts in a different part of the heart, the signal from the sinus node has an abnormal rate, or there's a "heart block" in which the signal is either partially or fully blocked before it gets to the ventricle. When this happens, a person may notice a change in the normal pattern of their heartbeat, which can result in:

• bradycardia - a very slow heart rate
• tachycardia - a very fast heart rate

Potential Causes:

• Lifestyle factors - stress, smoking, heavy alcohol use, heavy exercise, use of certain drugs (such as cocaine or amphetamines), use of certain prescription or over-the-counter medicines and too much caffeine or nicotine can lead to arrhythmia.
• Damage to the heart - a heart attack or an underlying condition that damages the heart's electrical system also can cause an arrhythmia. These conditions include high blood pressure, coronary artery disease, heart failure, overactive or underactive thyroid gland and rheumatic heart disease.
• Congenital problems - for some arrhythmias, the underlying heart defect that causes the arrhythmia is present at birth.

Types of arrhythmia

An arrhythmia is identified on the basis of where it occurs.

Ventricular arrhythmias - begin in the ventricles and are considered the most serious.

Ventricular tachycardia - the heart beats fast due to electrical signals arising from the ventricles instead of from the atria. Ventricular tachycardia can be life threatening.

Ventricular fibrillation - the heartbeat is both rapid and uncoordinated. As a result, the heart can't pump any blood and immediate medical help is essential. Untreated, ventricular fibrillation can quickly result in death.

Both ventricular tachycardia and ventricular fibrillation are very dangerous and can lead to cardiac arrest.

Ventricular arrhythmia - is premature ventricular contraction (PVC), in which the ventricles contract out of sequence with the normal heartbeat.

Atrial or supraventricular (above the ventricles) arrhythmias originate in the atria. Examples include:

• Atrial fibrillation
• Sinus arrhythmia - This is an arrhythmia in which cyclic changes in the heart rate occur during breathing
• Wolff-Parkinson-White syndrome - This is an arrhythmia in which abnormal pathways between the atria and ventricles cause very fast heart rates.

Treatment options 

If an arrhythmia is present, and it appears to be caused by heart disease, it's important to identify the underlying causes of the heart disease. The arrhythmia itself may also require treatment.

Ellis Medicine offers the following options:

• Surgical implantation of a defibrillator or an implantable cardioverter/defibrillator can monitor the heart's rhythm and use an electrical shock to bring it back to normal when necessary
• A pacemaker can send the proper electrical signals to make the heart beat normally. Pacemakers can be internal or external.
• Cardioversion or electrical cardioversion uses a machine which sends electrical energy to the heart muscle to help restore normal rhythm
• Ablation is a procedure which disconnects the pathways of the abnormal rhythm. In catheter ablation, a catheter or thin tube is inserted into a vein and guided to the heart, where it delivers energy - such as heat or cold - in order to destroy or isolate the source of the arrhythmia.
• Hybrid ablation may be an option for persistent atrial fibrillation. In hybrid ablation, electrophysiologist ablates from inside the heart and a cardiac surgeon ablates on the outside of the heart.
• Surgery can be an option for arrhythmias that don't respond to other treatments.