Types of Cardiac Arrhythmia

What are the different types of cardiac arrhythmias?

Originating in the Atria

Atrial Fibrillation (A Fib)

Atrial Fibrillation (also known as Auricular fibrillation, A Fib or AF) is the most common form of arrhythmia. A Fib is a rapid, irregular heartbeat. A Fib causes

Causes of A Fib

It is caused by quick, disorganized electrical signals sent to the atria causing them to beat quickly and abnormally. In a normal heartbeat, the electrical signals originate from the SA node. However, in the case of A Fib, the electrical signals originate in another region of the atria or in the pulmonary veins and spread throughout the atria causing them to fibrillate. The signals then move to the AV node causing the ventricles o also beat abnormally fast. Overall, this disorganized signal results in the atria and ventricles to beat out of sync causing an abnormal heart beat. Not only does this cause the atria to flood with blood, preventing all the blood from pumping into the ventricles, A Fib causes the ventricles to pump out random amounts of blood to the body.

Types of A Fib

There are three types of A Fib:

Paroxysmal A Fib: In the case of paroxysmal A Fib, the abnormal symptoms begin and end suddenly. Symptoms of this form can be mild to severe and usually last less than 24 hours.
Persistent A Fib: Persistent a Fib symptoms lasts longer than a week. This form may stop on its own or may need to be stopped with medication.
Permanent A Fib: In this form of A Fib, regular heart beat cannot be restored even with treatment. This form results gradually from frequent episodes of persistent and paroxysmal A Fib.

Symptoms of A Fib

Common symptoms of A Fib include:

A fluttering sensation in the chest
A rapid heart beat (heart palpitations)
A sensation that the heart has skipped a beat
Shortness of breath
Difficulty exercising
Chest pain
Dizziness
Fainting
Fatigue
Confusion

While an individual with A Fib may not exhibit any symptoms, it still can lead to severe complications such as stroke and heart failure.

Risk Factors of A Fib

A Fib is triggered by injury to the heart usually resulting from a heart related condition such as high blood pressure or coronary heart disease. Risk factors include

Age: The risk for A Fib increases with age, since the risk for conditions that can induce A Fib also increase with age.
High blood pressure
Coronary heart disease
Heart failure
Heart attack
Surgery
Rheumatic heart disease
Mitral valve prolapse and other structural heart defects
Pericarditis
Congenital heart defects
Sick sinus syndrome: a condition in which the electrical signals of the heart do not always fire resulting in a slow heartbeat.
Hyperthyroidism (a high level of thyroid hormone)
Obesity
Diabetes
Lung disease
Modest to excessive consumption of alcohol
Caffeine
Stress
Sleep Apnea
Metabolic syndrome (a group of risk factors for coronary heart disease, diabetes, stroke and other related conditions)
High doses of steroid therapy
Inflammatory conditions

A Fib Prevention

Living a healthy lifestyle can reduce the risk of developing A Fib and associated heart diseases. Healthy lifestyle changes include:

Heart healthy diet (daily variety of grains, fruits and vegetables with low levels of fat and cholesterol)
Quit smoking
Exercise
Maintaining a healthy weight

For individuals with risk factors for A Fib, it is recommended they:

Lower their blood pressure
Maintain healthy levels of cholesterol with diet or medications, if needed
Limit alcohol consumption
Individuals with diabetes should control blood sugar levels
Maintain a heart healthy diet

A Fib Treatment

The best treatment for A Fib depends largely on the symptoms and severity of the disease and heart disease comorbidity. Individuals with A Fib that do not show any symptoms or have any co-existing heart conditions may not need treatment. Treatments used for A Fib include:

Blood clot prevention (Blood thinning medications): The risk of stroke is high for individuals with A Fib since the blood pulling in the atria can clot together and travel to the brain. Blood clot prevention is one of the primary goals of A Fib treatment. Blood clots are prevented with blood-thinning medication such as warfarin, dabigatran, heparin and aspirin.
Rate Control (Beta and Calcium Channel Blockers): Medicine may also be prescribed to reduce the heart beat rate of the ventricles. These medications are recommended for most individuals with A Fib. While they may not bring the heart beat to a normal level, they significantly reduce the work the heart has to do. Heart rate is typically controlled with beta blockers (such as metoprolol and atenolol), calcium channel blockers (diltiazem and verapamil) and digitalis (digoxin).
Rhythm Control: For individuals in which rate control medications are not helping the condition, rhythm control medicines and procedures may be used. These treatments are often used in those that have just developed A Fib, since it is less likely to help the longer the patient has A Fib (especially for cases lasting longer than 6 months). Rhythm control treatments are also less effective in those that have a coexisting heart condition that has gotten worse or enlarged atria.

o Rhythm controlling medications include the new generations (amiodarone, sotalol, flecainide, propafenone, dofetilide, and ibutilide) and older therapies (quinidine, procainamide, and disopyramide)

o Rhythm controling procedures include

Cardioversion
Catheter ablation
Pacemaker
Maze surgery
Reducing risk factors: Another treatment option is to take actions to reduce risk factors for A Fib. These actions include:

o Taking medication to control overactive thyroid

o Lowering high blood pressure

o Managing high cholesterol

o Eating a healthy diet

o Reducing salt intake

o Quitting smoking

o Reducing stress

o Limiting alcohol, caffeine and other stimulants

Premature ventricular contractions

Premature ventricular contractions (also known as premature ventricular complexes, ventricular premature beats or ventricular extrasystoles) are extra beats of one of the ventricles. These extra heart beats are relatively common and often feel like a fluttering of the heart or like the heart has skipped a beat. This occurrence is of relatively little concern for individuals that experience it periodically and do not have a heart condition.

Symptoms of premature ventricular contractions include:

Heart fluttering
Heart pounding
Sensation that the heart has missed a beat
Increased awareness of the heart

These extra beats may occur because the ventricles are beating slightly out of order of when they should. This can occur when changes in the body cause the cells in the ventricles to become electrically unstable. Some situations include:

Taking specific medications (such as antihistamines and decongestants)
Consumption of alcohol or illegal substances
High levels of adrenaline due to caffeine, tobacco, exercise or anxiety
Heart damage from heart diseases such as coronary artery disease, congenital heart disease, high blood pressure or heart failure

Risk factors for extra heart beats include:

Substances that increase adrenaline (caffeine, tobacco, alcohol, illegal substances)
Exercise (for certain forms of the disease)
High blood pressure
Anxiety
Heart diseases (such a congenital heart disease, coronary artery disease, heart attack, heart failure, and cardiomyopathy (weakened heart muscle)

Premature ventricular contractions can be diagnosed through many ways. The most common method is using an electrocardiogram (ECG). If premature heartbeats are experienced infrequently, a portable monitoring device can be worn for a day to record electrical activity.

While in most healthy individuals premature ventricular contractions do not need to be treated, in individuals with heart problems, the condition may need to be managed. Common management strategies include lifestyle changes that reduce risk factors to reduce the frequency and severity. Medications, such as beta blockers, a medication commonly used to treat high blood pressure and heart disease, can also be used to reduce premature heartbeats. Medications for other arrhythmic conditions such as ventricular tachycardia medications amiodarone and flecainide could also help reduce this condition. In severe, refractory cases of premature heartbeat, radiofrequency catheter ablation may also be used. This is a procedure done to destroy regions of the heart responsible for the extra heartbeats.

Supraventricular Arrhythmia

Supraventricular arrhythmia or paroxysmal supraventricular tachycardia (SVT) is the sudden rapid beating of the heart for reasons other than exercise, fever and stress. There are three common types of SVT:

atrioventricular nodal reentrant tachycardia (AVNRT): The most common SVT. While seen in both males and females, it is more common in young women.
atrioventricular reciprocating tachycardia (AVRT): The second most common SVT. AVRT is mainly seen in younger individuals.
Atrial tachycardia: Atrial tachycardia is not caused by issues involving the AV node (like the other subtypes). It is commonly seen in individuals with coexisting heart disease

Other types of SVT include:

Sinus tachycardia
Inappropriate sinus tachycardia (IST)
Multifocal atrial tachycardia (MAT)
Junctional ectopic tachycardia (JET)
Nonparoxysmal junctional tachycardia (NPJT)

During SVT the heart beats between 100 and 300 times per minute (compared to 60 to 100 times per minute in a healthy individual).

SVT symptoms include:

Fluttering sensation in the chest
Rapid heartbeat
Shortness of breath
Lightheadedness
Dizziness
Sweating
A pounding sensation in the neck
Fainting (syncope)

In some individuals SVT comes and goes quickly; the induvial may not experience any symptoms at all. SVT symptoms can last a few minutes or a few days. SVT is primarily a concern in individuals that experience symptoms for long stretches of time and with a history of heart disorder.

There are a number of causes for SVT including:

Heart failure
Thyroid disease
Heart disease
Chronic lung disease
Smoking
Excessive alcohol consumption
Excessive caffeine consumption
Use of illicit drugs (i.e. cocaine and methamphetamines)
Use of certain medications such as asthma medications and over-the-counter cold and allergy drugs
Surgery
Pregnancy
Other health conditions, particularly Wolff-Parkinson-White syndrome

Risk factors of SVT include:

Age: SVT is the most common type of arrhythmia seen in children and infants. However, there are some forms that are more common in middle-aged and elderly individuals.
Sex: Women, especially pregnant women, are more likely to experience SVT
Heart disease such as coronary artery disease, narrowed heart arteries, heart attack, abnormal heart valves, heart failure, cardiomyopathy, other heart damage, congenital heart disease and heart surgery
Thyroid problems
Consumption of over-the-counter drugs (such as cough drops and cold medicine) as well as prescription drugs
Use of nicotine and illicit drugs (particularly amphetamines and cocaine)

Management and prevention largely involves identifying and avoiding triggers of SVT episodes. Other helpful actions include:

Healthy diet
Increased physical activity
Avoiding smoking
Maintaining a healthy weight
Limiting alcohol
Reducing stress
Obtaining adequate sleep
Limiting use of over-the-counter drugs
Avoiding illicit drug use
Maintain healthy blood pressure
Maintain healthy cholesterol levels
Practice yoga, meditation and other relaxation strategies

Similar to premature ventricular contractions, SVT may be diagnosed by use of a standard or portable ECG. An echocardiogram, which uses transducers placed on the chest, instead of electrodes, that emit soundwaves to generate images of the heart that include size, structure and motion. In other cases implantable loop recorders may be placed under the skin in the chest to detect abnormal heart beats. In addition to some of these tests, physicians may also test for other conditions that have been shown to associate with SVT like other heart diseases.

Although many cases of SVT do not require treatment, in individuals with symptoms that last for a long period of time or occur more frequently, the following may be recommended:

Cardio sinus massage
Vagal maneuvers
Cardioversion
Anti-arrhythmic medication
Catheter ablation

Atrial Flutter

As the name suggests, atrial flutter is the rapid beating (240-400 beats/min) of the atria. The rapid beating may also occur with a block on AV node conduction. This is different from A Fib in that the beating is more regular and organized with atrial flutter. There are two types of atrial flutter:

Typical (classic) atrial flutter (80% of cases): the electrical signal from the right atrium travels in a counterclockwise direction around the atrium
Atypical atrial flutter: Originate in the right atrium due to surgical scars or from the left atrium, especially after ablation procedures for A Fib.

Comorbidity

Atrial flutter is typically associated with (some of these conditions overlap):

Coronary artery disease (30% of cases
High blood pressure (30% of cases)
Surgical procedure and congenital heart diseases (26% of cases).
Unrelated to other heart diseases (30% of cases)
In rare cases, atrial flutter can result from

o Rheumatic heart disease

o Pericarditis

o Cardiomyopathy

o Mitral valve prolapse

o Acute myocardial infarction

o Hypoxia

o Chronic obstructive pulmonary disease

o Pulmonary embolism

o Hyperthyroidism

o Pheochromocytoma

o Diabetes

o Electrolyte imbalance

o Alcohol consumption

o Obesity

o Digitalis toxicity

o Myotonic dystrophy in childhood

Symptoms of Atrial flutter

Rapid heart beat
Fatigue
Difficulty breathing (dyspnea)
Chest pain

Diagnosis

Atrial flutter is typically diagnosed with

Treatments

Treatments center on controlling the ventricular response and sinus rhythm. Thus, electrical cardioversion is commonly used for those with unstable blood flow. Catheter-based ablation is associated with the best outcome for atrial flutter therapy. However, prognosis depends largely on comorbidity and the nature of the disease.

Epidemiology

Atrial flutter is far less common than A Fib. However, it is much more common in men. Approximately, three of every four cases occurred in men. It is also much more common in individuals 65 years old and older.

Wolff-Parkinson-White syndrome

Wolff-Parkinson-White syndrome or WPW is a rare congenital condition in which an additional electrical pulse is sent between the atria and ventricles, resulting in a rapid heartbeat. While the condition itself is not severe, it can lead to the development of more serious heart conditions.

Causes

The additional electrical pathway is the result of a genetic mutation. It may also occur in conjunction with Ebstein’s anomaly, a congenital heart disease. The additional electrical pathway bypasses the AV node causing the ventricles to beat too soon. The pathway can alter the heartbeat in two ways:

Looped electrical impulses: the pulses travel down the normal pathway and then back up the extra pathway or vise versa. This specific response is known as AV reentrant tachycardia.
Disorganized electrical impulses: occurs when the electrical impulses don’t begin in the right atrium resulting in dispersion across the atria in a disorganized way, leading to A Fib.

Symptoms

Common symptoms

Sensation of a rapid heartbeat, fluttering, or pounding in the chest (a few seconds to hours)
Dizziness
Lightheadedness
Shortness of breath
Fainting
Fatigue
Anxiety

Infants may have additional symptoms such as

Ashen color
Restlessness
Rapid breathing
Poor eating

Severe symptoms (10 to 30% of cases)

Development of A Fib resulting in A Fib symptoms

o Chest pain

o Chest tightness

o Difficulty breathing

o Fainting

Diagnosis

WPW can be diagnosed using

ECG (standard or portable)
Electricophysiological testing

Treatment

If an individual with WPW does not experience any symptoms, they may not need treatment. As is the case with most heart arrhythmia conditions, the type of treatment used depends on the severity and frequency of the condition. Potential treatments include:

Vagal maneuvers
Anti-arrhythmic medication
Cardioversion
Radiofrequency catheter ablation

Ventricular Arrhythmia (Originating in the Ventricles)

Ventricular Tachycardia

Ventricular tachycardia is a rapid heart rate (170 beats per minute) originating from the ventricles. This results in a decrease in blood pressure which prevents a sufficient amount of oxygen from reaching all the tissue in the body.

Symptoms

Dizziness
Lightheadedness
Sensation of a rapid heartbeat, pounding or heart flutter
Shortness of breath
Chest pain

In severe cases, ventricular tachycardia can lead to:

Fainting
Loss of consciousness
Cardiac arrest
Death

Comorbidity

Ventricular tachycardia typically occurs with another heart condition such as:

Coronary heart disease
High blood pressure
Cardiomyopathy
Heart valve disease
Following a heart attack
Following heart surgery

Risk factors

Risk factors for ventricular tachycardia include:

Specific medications
Electrolyte imbalance
Excessive consumption of caffeine
Excessive alcohol intake
Use of illicit drugs
Exercise
Genetic predisposition

Diagnosis

Ventricular tachycardia is typically diagnosed using a standard or portable ECG, or an electrophysiology test.

Common treatments include

Radiofrequency catheter ablation
Implantation of an implantable cardioverter defibrillator
Medications that slow down heart rate

Ventricular Fibrillation (V-Fib)

Similar to A Fib, ventricular fibrillation occurs when the heart displays erratic heart beat due to disorganized, rapid electrical impulses. However, in the vase of ventricular fibrillation, the ventricles quiver, resulting in inadequate pumping of blood to the lungs and body.

Ventricular fibrillation needs to be treated immediately. The condition usually causes blood pressure to drop rapidly, causing the individual to collapse almost immediately. It is one of the primary causes of sudden cardiac death.

Causes

V-Fib usually results from alterations in electrical signals sent through the heart after a heart attack or scars that form on the heart following a heart attack. Ventricular tachycardia may also contribute to the development of V-Fib.

Treatment

Cardiopulmonary resuscitation (CPR)
Defibrillation
Treatments for coronary artery disease

o Coronary angioplasty and stent placement

o Coronary bypass surgery

Risk factors for V-Fib

Previous v-fib episode
Previous heart attack
Congenital heart disease
Cardiomyopathy
Injury to the heart
Use of illicit drugs
Electrolyte imbalance

Prevention

To prevent sudden cardiac death, individuals with ventricular fibrillation are treated with medications and implanted devices such as pace makers to achieve and maintain normal heart rate.

Early signs of V-Fib include

Chest pain
Sensation of rapid heart beat
Dizziness
Nausea
Shortness of breath
Loss of consciousness

Diagnosis

V-Fib is only diagnosed during a medical emergency through monitoring heart beat or a pulse check in which no pulse can be detected. Causes of ventricular fibrillation can be determined using

ECG
Blood tests
Chest X-rays
Echocardiogram
CT scan
MRI
Coronary catheterization

Premature Ventricular Complexes (PVC)

Premature ventricular complexes (also known as PVC, ventricular premature beats, or ventricular extrasystoles) are additional of one of the ventricles. These additional beats result in the sensation of the heart skipping a beat due to a disrupted heartbeat. This condition usually does not need to be treated in healthy individuals not experiencing symptoms. However, if they occur frequenctly it could lead to the development of other arrhythmias or cardiomyopathy.

Symptoms:

Sensation of the heart skipping a beat
Fluttering, pounding, or jumping sensation in the chest
Heightened awareness of heartbeat

Causes and Risk Factors

Medications (including decongestants and antihistamines)
Alcohol use
Illicit drug use
High levels of adrenaline (resulting from caffeine, tobacco use, exercise or anxiety)
Injury to the heart

PVC is usually diagnoses through ECG. Treatments include leading a heart healthy lifestyle, use of beta blockers, or radiofrequency catheter ablation.