Arrhythmia: Symptoms, Risk Factors, Diagnosis, Complications, Treatment & Prevention

Last Updated on December 20, 2022 by Shabnam Sengupta

According to World Health Organization, cardiovascular diseases are one of the leading causes of death in the world. Every year, about 17.9 million people die due to such diseases. Cardiovascular diseases constitute of a number of heart and blood vessels disorders including coronary heart disease, cerebrovascular disease and rheumatic heart disease. The term “arrhythmia” literally means “out of rhythm”. A healthy heart beats with a certain rhythm of 60 to 100, regular beats per minute. An electric signal originating at a single site in the heart and spreading across the heart regulates these beats. This causes the heart to contract and pump blood producing the heartbeat. These electric signals are regular and occur a certain number of times in a minute which determines the heart rate.

The site of origin of these electrical signals is in the upper chambers (atria) of the heart. From there, they spread to the lower chambers (ventricles) resulting in a rhythmic contraction of the upper chambers followed by the lower chambers. This results in the receipt of blood into the upper chambers, the flow of blood from the upper to the lower chambers and the subsequent pumping of blood out of the lower chambers to the body.

Any condition which disturbs these electric signals will result in the heart beating out of rhythm called arrhythmia. There are numerous causes and types of arrhythmia. Arrhythmias can be regular, irregular, fast or slow. Some types of arrhythmias do not cause symptoms. Some people may not even notice it, while for some others, more severe arrhythmias can be fatal.

Classification of Arrhythmia

Based on the site of disturbance, arrhythmias can be of the following types:

1. Arrhythmias that begin above the lower chambers of the heart. These are supraventricular (above the ventricles) arrhythmias.
   1. Premature atrial contractions: These are beats that occur prematurely, before the upper chambers are filled with blood.
   2. Atrial tachycardia: An increase in electrical signals in the atria resulting in a higher heart rate.
   3. Atrial flutter: This is an arrhythmia of the upper chambers of the heart where the heart rate rises well above the normal rate but remains regular in most cases.
   4. Atrial fibrillation: Another arrhythmia of the upper chambers of the heart where the heart rate rises well above the normal rate and is irregular.
2. Arrhythmias that begin in the lower chambers of the heart
   1. Premature ventricular contractions: These are beats that occur in addition to or separate from the usual heartbeat.
   2. Ventricular tachycardia: An increase in heartbeat above the normal originating in the lower chambers of the heart.
   3. Ventricular fibrillation: An irregular arrhythmia with a very high heart rate in the lower chambers of the heart which results in a failure of the heart’s pumping mechanism and can be fatal.
3. Others:
   1. Heart block: A break or delay in the electrical signal that results in an irregular or decreased number of heartbeats. This break can occur anywhere in the path of the electrical signal.
   2. Sick sinus syndrome: In this, there is a decrease in heart rate due to abnormalities in the site where the electric signal originates.

Symptoms

Not all arrhythmias cause symptoms. When they do, they can be:

1. Palpitations are the most common symptom described as a racing heart
2. Sweating
3. Anxiety
4. Chest discomfort 
5. A flutter in the chest
6. Breathing difficulty
7. Lightheadedness and fainting
8. Weakness

Risk Factors of Arrhythmia

There are some risk factors for arrhythmias:

1. Age: The risk of arrhythmias increases with age with the increase in heart disease.
2. Hypertension: A high blood pressure and a resulting increase in the risk of heart disease can predispose to arrhythmias
3. People with a history of heart attacks are at a greater risk of developing arrhythmias.
4. Drugs: Drugs that can disturb the electrical signal in the heart can increase the risk of arrhythmias.
5. Genetic predisposition: The risk of arrhythmias can run in families
6. Congenital heart diseases: Children with congenital heart diseases are prone to arrhythmias
7. Endocrine disorders such as those affecting the thyroid can cause a higher or slower heart rhythm and irregular heartbeats.
8. Recreational drug abuse is associated with an increased risk of arrhythmias
9. Recently, covid-19 infections have been found to be a risk factor for heart disease and arrhythmias.

Diagnosis

The presence of arrhythmias can be diagnosed based on symptoms and a physical examination.

Tests performed for the assessment of the nature of the arrhythmia are:

1. Electrocardiogram (ECG) – Measures the electrical activity of the heart
2. Holter monitor – Also called continuous ambulatory electrocardiographic, monitor is a wearable ECG recorder used to monitor heart rate and rhythm for long durations
3. Echo – An echo is an imaging technique used to get a view of the heart’s structure and movement. 
4. Treadmill test – This test monitors the heart while performing physical exercise. 
5. Tilt table test
6. Cardiac catheterisation
7. Electrophysiological testing

Complications of Arrhythmia

Arrhythmias can result in the formation of blood clots within the heart which can break off and be pumped out of the heart into the body to form an embolus. This can cause a stroke.

Some arrhythmias can be fatal if not treated immediately.

Treatment

Treatment for arrhythmias depends very much on the cause, nature and severity of the arrhythmia.

Arrhythmias can be treated with drugs or other non-surgical and surgical methods.

Drugs

The most common drugs used in the treatment of arrhythmias are:

1. Beta-blockers
2. Calcium channel blockers
3. Sodium and potassium channel blockers
4. Adenosine
5. Atropine

Other therapies

Non-surgical

• Vagal manoeuvres: These are manoeuvres which stimulate the vagus nerve. The vagus nerve reduces the heart rate. These manoeuvres are useful in some supra ventricular arrhythmias.
• Cardioversion: In cardioversion, low energy shocks are delivered to the heart to restore the normal heart rate and rhythm. 
• Defibrillation: A technique that delivers high energy shocks to restore normal heart rhythm used in severe arrhythmias that can be fatal.

Surgical

1. Implantable cardioverter-defibrillator (ICD): This is a device that is surgically implanted under the skin in the chest and connected to the heart by wires. It tracks the heart rhythm and delivers electric shocks to the heart when it detects an arrhythmia. 
2. Pacemaker: This is another device that is implanted in the chest and connected to the heart. As the name suggests, the pacemaker maintains the heart rate by delivering low-energy electrical signals if the heart rate is slow.
3. Catheter ablation: A catheter is passed through the veins to the heart and is used to scar some tissue in the heart to obstruct aberrant electric signals and slow down the heart.

Prevention of Arrhythmia

1. As coronary heart disease and heart attacks can be one of the causes of arrhythmias, lifestyle changes and adequate management of hypertension and diabetes can be one of the preventive measures.
2. Avoiding recreational drugs, smoking, excessive alcohol consumption or excessive caffeine consumption.
3. Early diagnosis and treatment of thyroid disorders.
4. Only taking medicines associated with a risk of arrhythmias as and when prescribed by the doctor.

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