There are three Types of Heart Diseases.

• Electrical abnormality (Heart Rhythm abnormality=Heart Arrhythmia=Heart Rhythm disorders)
• Blood supply related abnormality
• Structural abnormality

---

Electrical abnormality (Heart Rhythm abnormality=Cardiac Arrhythmias)

Abnormal heart rhythms (abnormal heart beats) are caused by problems in the electrical system of the heart which maintains normal heart beats. The heart rate may become too slow, too fast or irregular. Some arrhythmias are dangerous and cause sudden cardiac death, while others may be bothersome but not life threatening.

---

Blood supply related abnormality

High blood pressure (Hypertension)

Coronary artery disease (Block in blood supply) is responsible for Heart attack

---

Structural abnormality

• Heart muscle related problems (Cardiomyopathy)
• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathy
• Infiltrative cardiomyopathy
• Heart Valve related problems

Electrical abnormality (Heart Rhythm abnormality=Cardiac Arrhythmias)

What is Cardiac Arrhythmia?

Cardiac Arrhythmia is any heart rhythm that is "abnormal."

Type of Cardiac Arrhythmias?

There are two broad categories of Cardiac Arrhythmias

• 1. Abnormally slow heartbeats (Bradycardia)
• 2. Excessively fast heartbeats (Tachycardia)

Bradycardia is a slow heartbeat, less than 60 beats per minute, which can be normal.

Each day, a normal heart beats about 100,000 times, at a rate anywhere from 60 to 100 beats per minute. Changes in heart rate caused by physical activity are normal. At certain times, such as during sleep, heart rate will be slow and still be normal.

Abnormally slow heart rates are usually those below 60 beats a minute and can be either harmless or life threatening.

---

Sinus Node Disease (SA Node disease)

• An abnormally slow natural “pacemaker” in the heart.
• The heart has a group of cells in the upper chamber (right atrium) called the sinus node (SA Node) that generates an electrical signal, to travel through the atrium to the lower chambers (left and right ventricles) causing them to contract, making a heartbeat about once every second at rest.
• The sinus node can increase its rate of generating electricity depending on the body’s needs.
• This natural pacemaker can become dysfunctional with age and generates electricity too slowly or sometimes fail entirely, resulting in slow heart rates.

---

Heart Block (AV Node disease)

• Blockage of the electric wire connection (AV Node) that carry the electric current from the atria to the ventricles.
• The ventricles will only contract to cause a heartbeat when they receive these electrical current.
• In this case, the natural pacemaker (SA Node) is generating electricity normally, but the electricity does not reach the ventricles.
• There are three kinds of heart block: first-degree, second-degree, and third-degree. (complete heart block - CHB).
• This dysfunction AV Nodal electrical connection leads to slow heart beats.

---

Tachy-brady syndrome or Sick Sinus Syndrome (SSS)

• Sick Sinus Syndrome is a group of signs or symptoms in which the heart’s natural electrical pacemaker, the sinus node (SA Node), is not working properly.
• In SSS, the heart rate can alternate between slow (bradycardia) and fast (tachycardia).
• Treatment of SSS is usually an artificial pacemaker, along with medication.
• A pacemaker to prevent the heart from beating too slowly and taking medicines to stop the heart from beating too fast.

Two categories of Tachyarrhythmia (Based on Location of Arrhythmias Short-Circuits)

• 1. Supraventricular tachycardia (SVT) (fast heart beats that begin in upper chambers known as atria)
• 2. Ventricular tachycardia (VT) (fast heart beats that begin in lower chambers known as ventricles)

---

Supraventricular Tachycardia (SVT)

---

Atrial Fibrillation (AF)

• This is a rapid, irregular rhythm of the upper heart chambers secondary to multiple electric short-circuits
• The upper chambers beat at 300-500 beats per minute
• Even though the upper chambers are beating this rapidly, the normal electrical junction box, or AV node located between the upper and lower chambers of the heart, only allows limited electrical impulses to reach the ventricles.
• Therefore the actual pulse rate felt at a patient’s wrist is only 100-150 per minute.
• When this occurs, the upper chambers of the heart begin to fibrillate, instead of contracting normally.
• AF can lead to palpitations, fatigue, and heart failure.
• In patients with atrial fibrillation, contraction of the atrial muscle may not be very efficient. In such cases, blood clots can form inside of the atria and could even break off and travel to other parts of the body causing a brain stroke or blockage in an artery in a limb or abdomen.
• Chances of having a brain stroke are five times higher for those with AF.
• Doctor may prescribe blood thinners to reduce risk of having a brain stroke.

---

Atrial Flutter (AFL), Atrial Tachycardia (AT)

• This is an rapid, regular rhythm of the upper heart chambers secondary to single electric short-circuit.
• The upper chambers beat at 200-300 beats per minute.
• Even though the upper chambers are beating this rapidly, the normal electrical junction box, or AV node located between the upper and lower chambers of the heart, only allows limited electrical impulses to reach the ventricles.
• Therefore the actual pulse rate felt at a patient’s wrist is only 100-150 per minute.
• In patients with atrial flutter, contraction of the atrial muscle may not be very efficient. In such cases, blood clots can form inside of the atria and could even break off and travel to other parts of the body causing a brain stroke or blockage in an artery in a limb or abdomen.
• Doctor may prescribe blood thinners to reduce risk of having a brain stroke.

---

Ventricular Arrhythmias (VAs)

---

Syncope = Fainting / Fall / Blackouts / Giddiness / Dizziness / Chakkar / Feeling of Imbalance

Patients presenting with a history of blackouts, faints or collapse need careful evaluation to assess the precise nature of the problem.

Analysis of Syncope is essential so as to assess both the risk of a serious underlying disorder and also the risk of recurrence.

---

Etiology of Syncope

• 1. Neurally mediated syncope (NMS) - also called Reflex syncope/Vasovagal syncope
• 2. Orthostatic hypotension (postural hypotension) - syncope occurs after standing up
• 3. Cardiac arrhythmias: Bradyarrhythmias, Tachyarrhythmias (serious problems)
• 4. Other causes

---

Complications of Syncope

• 1. Recurrent syncope has serious effects on quality of life.
• 2. Morbidity is particularly high in the elderly and includes loss of confidence, reduced mobility, depression, fear of falling and bone fractures.
• 3. Physical injury: soft tissue and bone injuries may occur due to fall.

---

Assessment and Investigations (Risk stratification)

• 1. Blood pressure (Orthostatic)
• 2. ECG (Detail analysis)
• 3. Echocardiogram
• 4. Treadmill test (TMT)
• 5. Holter monitoring
• 6. Head-Up Tilt Table (HUTT) testing
• 7. External loop recording (ELR)
• 8. Implantable loop recorder (ILR)
• 9. EP study
• 10. Cardiac MRI
• 11. Coronary angiography (CAG)

Sudden cardiac death (SCD) is a sudden, unexpected death caused by a change in heart rhythm (Sudden Cardiac Arrest).

What is Sudden Cardiac Arrest and How is it different from a heart attack?

Sudden cardiac arrest is not a heart attack but can occur during a heart attack.

Heart attack occurs when there is a blockage in blood supply to the heart. If the oxygen in the blood cannot reach the heart muscle, the heart becomes damaged.

Sudden Cardiac Arrest occurs when the electrical system of the heart suddenly becomes very irregular and abnormal. The heart beats dangerously fast due to electric short-circuits. Sudden Cardiac Arrest due to electric short-circuits (ventricular fibrillation), leads to severe fall in blood pressure and person will lose consciousness. Death follows unless emergency treatment is given immediately.

Emergency treatment of Sudden Cardiac Arrest includes cardiopulmonary resuscitation (CPR) and defibrillation.

• 1. Cardiopulmonary resuscitation (CPR):It is a manual technique using repetitive chest compression and breathing into the person's airways that keeps enough oxygen and blood flowing to the brain.
• 2. Defibrillation: It is a technique where normal heart rhythm is restored with an electric shock to the chest. Emergency team use portable defibrillators and public access defibrillators (AEDs, automated external defibrillators) to deliver an electric shock to the patient.

---

What are the causes of Sudden Cardiac Arrest?

Most sudden cardiac deaths are caused by heart rhythm abnormality. The most common life-threatening heart rhythm abnormality is ventricular fibrillation, which is an erratic, disorganized firing of impulses from the ventricles due to electric short-circuits.

---

What are the risk factors of Sudden Cardiac Arrest?

• 1. Previous heart attack with a large area of damaged heart muscles.
• 2. Prior episode of sudden cardiac arrest
• 3. Family history of sudden cardiac arrest or SCD
• 4. Genetic problem related abnormal heart rhythm (long or short QT syndrome, Brugada syndrome, ARVC, CPVT, WPW syndrome)
• 5. History of syncope (fainting episodes of unknown cause)
• 6. Heart failure (Weaker heart's pumping, LVEF less than 35%)
• 7. Hypertrophic Cardiomyopathy (thickened heart muscle of the ventricles)
• 8. Dilated Cardiomyopathy (Enlarged heart)
• 9. Complete Heart block
• 10. Drug abuse (Cocaine and others)

---

Assessment and Investigations in case of Sudden Cardiac Arrest?

• 1. ECG (Detail analysis)
• 2. Echocardiogram
• 3. Treadmill test (TMT)
• 4. Holter monitoring
• 5. External loop recording (ELR)
• 6. Implantable loop recorder (ILR)
• 7. EP study
• 8. Cardiac MRI
• 9. Coronary angiography (CAG)
• 10. Genetic analysis
• 11. Family screening

---

Can Sudden Cardiac Arrest be prevented?

If you have any of the risk factors for sudden cardiac death, it is important to consult cardiac electrophysiologist and speak about possible steps to reduce your risk.

• 1. Assessment and investigations (as mentioned above)
• 2. Lifestyle modification
• 3. Medications
• 4. Heart failure management
• 5. Implantable cardioverter defibrillator (ICD)
• 6. Interventional Procedures or Surgery like angioplasty, EP study & catheter ablation
• 7. Educating Family Members

---

Can Sudden Cardiac Arrest be treated?

Yes, sudden cardiac arrest can be treated, but emergency action must take place immediately.

• There are several types of inherited Heart Rhythm Abnormality. The most common types include:

• Long QT syndrome (LQTS)
• Short QT syndrome (SQTS)
• Brugada syndrome (BrS)
• Catecholaminergic polymorphic ventricular tachycardia (CPVT)
• Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D)
• Early repolarization syndrome (ERS)
• Idiopathic ventricular fibrillation (IVF)
• Inheritable cardiomyopathies

• Genetic Heart Rhythm disorders need a multi-subspecialty approach to management of patients and their family members who have a confirmed diagnosis or who are seeking an opinion regarding a possible diagnosis of a genetic arrhythmia disorder.
• Cardiac Electrophysiologist specialized in inherited arrhythmia disorders should evaluate such cases.

---

Long QT Syndrome (LQTS)

• Long QT Syndrome is a genetic disorder of the electrical system of heart.
• People with LQTS are at risk for VF, the most dangerous heart rhythm that causes sudden death.
• Heart rhythm abnormality can occur suddenly, leading to fainting or sometimes cardiac arrest and sudden death.
• Most hereditary forms of the LQTS occur in people who inherit only a single genetic variant from one of their parents.
• Jervell and Lange-Nielsen syndrome (JLN syndrome) usually occurs at a younger age, and the symptoms are more severe.
• JLN syndrome children are usually born deaf and have LQTS because they inherit two genetic changes, one from each parent.

---

Short QT Syndrome (SQTS)

• Short QT Syndrome is a genetic disorder of the electrical system of heart.
• People with SQTS are at risk for VF, the most dangerous heart rhythm that causes sudden death.
• Heart rhythm abnormality can occur suddenly, leading to fainting or sometimes cardiac arrest and sudden death.
• Short QT syndrome usually affects young, healthy people with no structural heart disease.
• It may occur as an isolated case, or it may be present in families.

---

Brugada Syndrome (BrS)

• Brugada syndrome is a genetic disorder of the heart rhythm.
• Brugada syndrome can cause fainting due to ventricular fibrillation and sudden cardiac arrest.
• Brugada syndrome is most common in people of Asian origin.
• It is more likely found in males.
• It most commonly affects healthy people of 30–50 years age.
• Most cases are inherited from a parent who has Brugada syndrome.

---

Catecholaminergic polymorphic ventricular tachycardia (CPVT)

• CPVT is a disorder of the calcium channels in the heart muscle.
• CPVT results in problems with electrical signalling and irregular heartbeats, especially during exercise.
• CPVT can cause fainting due to polymorphic VT/VF and even sudden cardiac arrest during exercise.

---

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D)

• Arrhythmogenic right ventricular cardiomyopathy is a genetic disorder of heart rhythm.
• In ARVC, the heart muscle is gradually replaced by fat tissue.
• ARVC may lead to episodes of rapid Heart Rhythm abnormality like VT and VF.
• ARVC can cause sudden cardiac arrest and death due to ventricular arrhythmias.

---

Hypertrophic cardiomyopathy (HCM)

• Hypertrophic cardiomyopathy is the most common inherited heart disorder.
• HCM affects approximately 1 in every 500 people.
• It occurs when the left ventricle of the heart is thicker than normal.
• This reduces the heart’s ability to pump blood.
• HCM can cause sudden cardiac arrest and death due to ventricular arrhythmias.

---

Dilated cardiomyopathy (DCM)

• Dilated cardiomyopathy is seen in approximately 1 in 2,500 people.
• Dilated cardiomyopathy leads to an enlarged left ventricle and reduced pumping function.
• The enlargement is a result of a weakened heart muscle.
• Studies have shown that 20-35% of primary dilated cardiomyopathy is linked to genetics.
• DCM can cause sudden cardiac arrest and death due to ventricular arrhythmias.

Introduction

• Atrial Fibrillation (AF) is the most common sustained heart rhythm abnormality (Irregular Heart Rhythm).
• AF is caused by chaotic electrical signals due to multiple short circuits in the upper chambers of heart (Atria)
• AF makes the upper chambers of the heart fibrillate, instead of fully contracting.
• In AF, the atria may beat as often as 300-500 times a minute.
• Due to pooling of blood in atria during AF, there is an increased chance of blood clot formation.
• If a blood clot dislodges from the atria, it can cause a brain stroke.
• AF can lead to heart failure and to other conditions that cause patients to feel tired, dizzy, and short of breath.
• AFib is a progressive condition, meaning that if it is not treated, it can worsen. When this occurs, episodes tend to become more frequent and last longer.
• It is important to see a doctor if you have symptoms of AF, because it becomes harder to treat once episodes become more persistent.

---

Risk Factors for AFib

• Age (elderly, more than 65 years)
• Hypertension
• Diabetes
• Coronary artery disease (Heart attack due to block in blood supply to heart muscles)
• Heart valve abnormality
• Heart failure
• Genetic causes
• Untreated atrial flutter
• Prior open-heart surgery
• Obstructive Sleep apnea syndrome (OSAS)
• Thyroid disease
• Chronic lung disease
• Excessive alcohol intake
• Serious illness or infection

---

Symptoms of AF

• Feeling tired or fatigue
• Faster and irregular heartbeats (Palpitations)
• Shortness of breath
• Trouble with everyday exercises or activities
• Dizziness, light-headedness, or fainting

---

Diagnosis of AF

• ECG
• Holter monitoring
• Loop recorder
• Sleep study (Polysomnography)

---

Treatment of AF

• (1) Medical Management
• Brain stroke prevention (Optimal anti-coagulation by blood thinner medicines)
• Heart rate control
• Heart rhythm control
• Treatment of risk factors
• CPAP therapy for OSAS
• (2) DC Cardioversion
• (3) 3D Mapping & RF catheter ablation (PV Isolation)