AHHA

Heart and cardiovascular diseases

Arrhythmia

What is an Arrhythmia?

An arrhythmia is an irregular or abnormal heartbeat. The heart can beat too fast, too slow or irregularly in arrhythmia. Arrhythmia is also called as Dysrhythmia.

To Understand Arrhythmia better need to Understand the Heart’s Electrical System

The rate and rhythm of the heart beat is controlled by the heart’s electrical system. An electrical signal spreads from top of the heart to the bottom with each heartbeat causing heart to contract and pump the blood. In the heart’s upper right atrium of the right chamber sinoatrial (SA) node, a group of cells is located and is responsible to fire off these electrical signals making heart to beat 60 to 100 times per minute. Through a special pathway the electrical signal from the SA node travels to the right and left atria causing atria to contract and pump blood into the two lower chambers, the ventricles of heart. Then the electrical signal moves down between the atria and the ventricles to a group of cells called the atrioventricular (AV) node where the signal slow down for an instant to allow the ventricles to fill with blood.

Then the electrical signal leaves the AV node and through the pathway reaches the bundle of His where the pathway divides into a right bundle branch and a left bundle branch allowing signal to go down these branches to the ventricles causing ventricles to contract and pump blood to the lungs and the rest of the body and then ventricles relax. After that again the heartbeat process starts. Hence a problem with any of this process can cause arrhythmia.

Normal Heartbeat Rate:


Age group

Normal Heart Rate

New born

100 to 160 per minute

Children (1-10)

90-120 per minute

Older children

70-100 per minute

Adults

60-100 per minute

Athletes

Less than 60

Types of Arrhythmia

The four main types of arrhythmias are:

  • Premature beats(extra beats)
  • Supraventricular arrhythmias
  • Ventricular arrhythmias
  • Bradyarrhythmias

Premature Beats(extra beats)

Premature beats is the most common type and most of time it is harmless and don’t often have any symptoms. If there is any symptoms it usually feel like fluttering in the chest or as if a skipped heartbeat. The premature beats occurred in atria is known as the premature atrial contractions, or PACs and in ventricles is known as premature ventricular contractions, or PVCs.

In many cases the premature beats don’t need any treatment as it happens naturally. But in some cases some heart disease can cause it. Also it can occur due to stress, excessive amount of caffeine, nicotine or exercise.

Supraventricular Arrhythmias

Supraventricular arrhythmias are the fast heart rates (tachycardias). It starts in the atria (upper chambers) or the AV node. Supraventricular arrhythmias include:

  • Atrial fibrillation(AF)
  • Atrial flutter
  • Paroxysmal supraventricular tachycardia (PSVT)
  • Wolff-Parkinson-White(WPW) syndrome

Atrial Fibrillation

In atrial fibrillation (AF) the atria contracts very fast and irregularly. Hence AF is the most common type of serious arrhythmia. In a common process the heart’s electrical signals begins at SA node but in AF instead of SA the electrical signals begin in other parts. Also instead of a normal pathway they electrical signal spread throughout the atria in a rapid and disorganized way causing the walls of the atria to quiver very fast instead of beating normally. Resulting, the inability in pumping blood to the ventricles in the normal way as it should have.

In normal condition SA node fires off the electrical signal making heart to beat 60 to 100 times per minute but in AF the abnormal signals can spread making heart to beat more than 300 per minute and also can travel some of it to the ventricles causing them to beat fast too.

The damage to heart’s electrical signal  are often the result of other conditions such as high blood pressure, coronary heart disease, and rheumatic heart disease which is direct cause to affect heart. As well as inflammation or overactive thyroid gland can cause AF. Also heavy alcoholism can lead to AF.

The major two complications due to AF are heart failure and stroke and the risk increases with age.

Atrial Flutter

Atrial flutter is quite similar to atrial fibrillation the only difference is the heart’s electrical signals which spread through the atria in a fast and regularinstead of fast and irregular. It is less common than AF but it has similar symptoms and complications.

Paroxysmal Supraventricular Tachycardia

Paroxysmal supraventricular tachycardia (PSVT) is a very fast heart rate that begins and ends suddenly and is cause due to the problem with the electrical connection between the atria and the ventricles. The electrical signals which begin in atria and travel to ventricles can again enter the atria causing extra heartbeats. It is tends to occur in young people and usually is undangerous. It can happen during heavy physical activity.

Wolff-Parkinson-White(WPW) syndrome

Wolff-Parkinson-White (WPW) syndrome is a special type of PSVT. In this type of arrhythmia the heart’s electrical signals travels from the atria to the ventricles with an extra pathway which can disrupts the timing and causing the ventricles to beat very fast.  This type of arrhythmia can be dangerously life threatening.

Ventricular Arrhythmias

Ventricular arrhythmias start in the ventricles(the lower chambers) and can very dangerous needing medical attention. It can be caused due to coronary heart disease, heart attack, a weakened heart muscles or other problem with heart. Ventricular arrhythmias include:

  • ventricular tachycardia
  • ventricular fibrillation

Ventricular Tachycardia

In ventricular tachycardia the ventricles (lower chambers of heart) beats regular but very fast. It may last for only few seconds or much longer. If it beats few seconds then often it doesn’t cause problem but if the beating last for more than a few second than it can be dangerous. This ventricular tachycardia can turn in ventricular fibrillation which is much serious arrhythmia.

Ventricular Fibrillation

In ventricular fibrillation (V-fib) due to disorganized heart’s electrical signals the ventricles quiver (fibrillate) instead of pumping normally causing ventricle to not to pump blood to the body. Without blood supply for few minutes, serious complications like sudden cardiac arrest and even death can occur. It often occurs when there is heart attack or if the heart is weak due to other condition. When V-fib occurs it’s better to give electric shock to the heart immediately to prevent death. The electric shock is called as defibrillation.

Bradyarrhythmias

If the heart rate is slower than 60-100 per minute in an adult bradyarrhythmias occur. When the heart rate is slow brain will be deprived from enough blood causing people to faint. But however for athletes who are physically fit the heart rate can be lower than 60 per minute which is normal and is not dangerous.

Bradyarrhythmias can be caused by some serious diseases or other condition such as heart attack, underactive thyroid gland, imbalance of chemicals in blood, medicines such as beta blockers, calcium channel blockers. Also due to aging bradyarrhythmias can be caused.

Causes of an Arrhythmia

Arrhythmias can be caused due to various factors:

  • Coronary artery disease
  • High blood pressure
  • Changes in the heart muscle (cardiomyopathy)
  • Valve disorders
  • Electrolyte imbalances in the blood, such as sodium or potassium
  • Injury from a heart attack
  • The healing process after heart surgery
  • Diabetes
  • Overactive thyroid gland (hyperthyroidism)
  • Smoking
  • Drinking too much alcohol or caffeine
  • Drug abuse
  • Stress
  • Medications
  • Dietary supplements and herbal treatments
  • Electrical shock

Symptoms of an Arrhythmia

Many arrhythmias can be “silent” and don’t cause any symptoms. If symptoms occur the most common may include:

  • Palpitations: A feeling of skipped heartbeats, fluttering
  • A slow heartbeat
  • An irregular heartbeat
  • Feeling a pause between heartbeats

More serious may include:

  • Anxiety
  • Pounding in the chest
  • Dizziness or feeling lightheaded
  • Shortness of breath
  • Chest pain and discomfort
  • Weakness or fatigue
  • Sweating
  • Fainting or nearly fainting

Who is at the risk of an Arrhythmia?

Arrhythmias come with aging hence it is very common in older adults. Most serious arrhythmias affect people older than 60 as they are more likely to have heart disease and other problems related to heart which can cause arrhythmias.  Also some side effects of medicines which are used to treat arrhythmias can cause arrhythmias.

Paroxysmal supraventricular tachycardia(PSVT), including Wolff-Parkinson-White syndrome, is more common in young people and children.

Major Risk Factors

People with heart disease or condition which weaken the heart tend to have arrhythmias. Conditions such as:

  • Heart attack
  • Heart failure or cardiomyopathy
  • Heart tissue that is too thick or stiff or that hasn’t formed normally
  • Leaking or narrowed heart valves, which make the heart work too hard and can lead to heart failure
  • Congenital heart defects
  • High blood pressure
  • Infections that damage the heart muscle or the sac around the heart
  • Diabetes, which increases the risk of high blood pressure and coronary heart disease
  • Sleep apnea, which can stress the heart because the heart doesn’t get enough oxygen
  • An overactive or underactive thyroid gland
  • Heart surgery
  • Drugs like cocaine
  • Imbalances of chemicals in the blood, such as sodium or potassium

Diagnosis of an Arrhythmia

Some arrhythmias can be hard to diagnose as some types cause symptoms every once in a while hence, doctors diagnose arrhythmias based on medical and family histories, a physical exam, and the results from tests and procedures.

Medical and Family Histories

The doctor may ask series of question regarding the symptoms of arrhythmia also may ask if patience is suffering from other health problems which can lead to heart disease or heart related disease itself.  Also may ask if the patience smoke or use alcohol or drugs, has stress and etc.

Further the doctor may ask regarding the background of patience’s family if any of the sibling or parents had a history of heart related disease or hypertension, had sudden cardiac arrest, history of arrhythmia or other heath issues.

Physical Examination

The doctor may listen to the heartbeat to find out the rhythm and rate.  Also listen to find if there is any murmur sound during heartbeat. Check for pulse and swellings. Also look for signs of other diseases.

Tests and Procedures

Some of the tests and procedures will be prescribed.

Laboratory Test

  • Blood test

Imaging Tests

  • Electrocardiogram (ECG or EKG)
  • Echocardiogram(ECHO)
  • Stress Test
  • Tilt table test
  • Holter monitor
  • Chest X-ray

Invasive Testing

  • Cardiac catheterization
  • Electrophysiology study (EPS)

Treatments of an Arrhythmia

Treatment of arrhythmia depends upon the seriousness and its symptoms. The treatment includes:

Lifestyle Changes

There are some lifestyle factors which can cause arrhythmias. Hence the first step is to change the habits which could help to reduce the risk of arrhythmias, some of them are:

  • Quitting smoking or tobacco using 
  • Reduce alcoholism
  • Reduce consumption of caffeine in excessive amount

Medicines

A combination of medicines will be prescribed which may include:

  • Antiarrhythmics
  • Beta blockers
  • Calcium channel blockers
  • Digoxin
  • Aspirin
  • Warfarin
  • Dabigatran
  • Heparin

These medicines can help in:

  • To restore a normal heart rhythm
  • To slow down fast beating heart to slow
  • To change an abnormal heart rhythm to a normal, steady rhythm
  • To lower blood pressure;
  • To reduce the risk of blood clots forming

Medical Procedures

  • Electrical cardioversion or defibrillation
  • Catheter ablation
  • Permanent pacemakers
  • Implantablecardioverterdefibrillator

SurgicalProcedure

  • Maze procedure
  • Ventricular aneurysm surgery
  • Coronary artery bypass grafting

Other Treatments

Vagal maneuvers: It is a simple exercise or technique which can sometime help to halt or slow down a fast heartbeat. It is used to treat an arrhythmia that begins above the lower half of the heart (supraventricular tachycardia, or SVT). The vagus nerve is been affected by the maneuvers which help to control the heart rate.  Doctor’s advice to practice this maneuver is very crucial, as it is not applicable for everyone. Some of the vugal maneuvers may include:

  • Holding the breath and straining
  • Gagging
  • Immersing the face in the ice-cold water
  • Coughing
  • By the help of fingers, pressing down the eyelids gently

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