Cardiac Arrhythmias: Types, Symptoms and Treatment

What is a Cardiac Arrhythmia?

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Normal heart rhythm is regulated by electrical impulses originating from the sinus node. These impulses spread to the heart chambers, enabling coordinated contraction. Normal resting heart rate is 60-100 beats per minute.

Arrhythmia is the irregularity, acceleration, or slowing of heart rhythm due to disturbances in this electrical system. Arrhythmias can range from harmless palpitations to life-threatening conditions.

The Heart’s Electrical Conduction System

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Sinus Node (SA Node)

• The heart’s natural pacemaker
• Located in the right atrium
• Initiates normal rhythm (60-100/min)

Atrioventricular Node (AV Node)

• Provides conduction from atria to ventricles
• Acts as a gateway
• Slows conduction for coordination

Bundle of His and Purkinje Fibers

• Rapid conduction to ventricles
• Enables coordinated contraction

Types of Arrhythmias

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Arrhythmias are classified by heart rate and origin:

Classification by Rate

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Tachycardia (Fast Heart Rate)

• Heart rate > 100 beats/minute
• Sinus tachycardia, SVT, VT, AF

Bradycardia (Slow Heart Rate)

• Heart rate < 60 beats/minute
• Sinus bradycardia, AV blocks, sick sinus syndrome

Classification by Origin

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Supraventricular Arrhythmias (Atrial Origin)

Atrial Fibrillation (AF)

• Most common sustained arrhythmia
• Irregular, rapid atrial contractions
• Increased stroke risk
• Palpitations, shortness of breath, fatigue

Atrial Flutter

• Regular but rapid circuit in atria
• Usually 300/min atrial rate
• Similar symptoms to AF

Supraventricular Tachycardia (SVT)

• Sudden onset and termination
• Heart rate 150-250/min
• Usually benign
• AVNRT, AVRT, atrial tachycardia

Premature Atrial Contractions (PACs)

• Early atrial beats
• Often harmless
• Sensation of palpitations

Ventricular Arrhythmias

Ventricular Tachycardia (VT)

• Rapid rhythm originating from ventricles
• Can be life-threatening
• Associated with structural heart disease
• Sustained VT requires emergency intervention

Ventricular Fibrillation (VF)

• Most dangerous arrhythmia
• Heart stops pumping
• Cause of sudden cardiac death
• Requires immediate defibrillation

Premature Ventricular Contractions (PVCs)

• Early ventricular beats
• Usually harmless
• Frequent PVCs should be evaluated

Conduction Disorders

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AV Blocks

• First Degree: PR prolongation, usually harmless
• Second Degree (Mobitz I/II): Some beats not conducted
• Third Degree (Complete block): Atrial-ventricular connection severed, requires pacemaker

Bundle Branch Blocks

• Left bundle branch block (LBBB)
• Right bundle branch block (RBBB)
• Fascicular blocks

Causes and Risk Factors

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Cardiac Causes

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• Coronary artery disease and heart attack
• Heart failure
• Heart valve diseases
• Cardiomyopathies
• Congenital heart diseases
• Myocarditis (heart muscle inflammation)
• Post-cardiac surgery

Non-Cardiac Causes

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• Electrolyte imbalances (potassium, magnesium)
• Thyroid disorders
• Medications and toxic substances
• Excessive caffeine or alcohol
• Drug use
• Stress and anxiety
• Sleep apnea
• Fever and infections

Risk Factors

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• Advanced age
• Hypertension
• Diabetes
• Obesity
• Smoking

Arrhythmia Symptoms

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Symptoms of arrhythmias vary depending on type, duration, and heart function:

Common Symptoms

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Palpitations

• Most common complaint
• Awareness of heartbeats
• Sensation of fast, irregular, or skipped beats

Dizziness and Lightheadedness

• Decreased blood flow to brain
• Especially with sudden-onset arrhythmias
• Fainting (syncope) is a serious symptom

Shortness of Breath

• Decreased cardiac output
• May worsen with exertion

Chest Pain or Discomfort

• Heart working excessively
• May indicate coronary insufficiency

Fatigue and Weakness

• Due to low cardiac output
• Exercise intolerance

Diagnostic Methods

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Arrhythmia diagnosis is made through clinical evaluation and various tests:

ECG (Electrocardiography)

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• First-line diagnostic method
• Records heart’s electrical activity
• Determines arrhythmia type
• 12-lead standard ECG

Holter Monitoring

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• 24-48 hour continuous ECG recording
• Detection of intermittent arrhythmias
• Correlation with symptoms
• Monitoring during daily activities

Event Recorders

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• Long-term monitoring (1-4 weeks)
• Patient-activated during symptoms
• Capturing rare arrhythmias

Implantable Loop Recorder (ILR)

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• Small device placed under skin
• 2-3 years continuous monitoring
• Investigation of unexplained syncope
• AF screening after cryptogenic stroke

Electrophysiology Study (EPS)

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• Invasive diagnostic method
• Intracardiac recordings via catheter
• Determining arrhythmia mechanism
• Mapping for ablation therapy

Other Tests

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Echocardiography

• Evaluating structural heart diseases
• Left ventricular function
• Valve diseases

Exercise Stress Test

• Exercise-induced arrhythmias
• Coronary artery disease evaluation

Blood Tests

• Electrolyte levels
• Thyroid function
• Cardiac markers

Treatment Methods

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Arrhythmia treatment is planned according to arrhythmia type, severity, and underlying cause:

Lifestyle Modifications

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• Caffeine and alcohol restriction
• Smoking cessation
• Stress management
• Regular sleep
• Healthy diet
• Avoiding triggers

Medication Therapy

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Antiarrhythmic Drugs

Class I (Sodium Channel Blockers)

• Propafenone, flecainide
• Used in SVT and AF

Class II (Beta Blockers)

• Metoprolol, bisoprolol
• Heart rate control
• First choice for most arrhythmia types

Class III (Potassium Channel Blockers)

• Amiodarone, sotalol, dronedarone
• Broad-spectrum antiarrhythmic effect
• AF rhythm control

Class IV (Calcium Channel Blockers)

• Diltiazem, verapamil
• Rate control in SVT and AF

Rate Control vs Rhythm Control

• Two main strategies in AF
• Selection based on individual patient characteristics
• Rate control generally easier

Anticoagulant Therapy

• Stroke prevention in AF
• Based on CHA₂DS₂-VASc score
• Warfarin or NOACs

Catheter Ablation

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• Destruction of arrhythmia source with radiofrequency or cryotherapy
• High success in SVT (95%+)
• AF ablation (pulmonary vein isolation)
• VT ablation

Indications

• Drug-resistant arrhythmias
• Drug side effects
• Patient preference
• Young patients without structural heart disease

Device Therapies

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Pacemaker

• For bradycardia treatment
• In AV block and sick sinus syndrome
• Single or dual chamber systems

ICD (Implantable Cardioverter Defibrillator)

• For ventricular arrhythmias
• Prevention of sudden cardiac death
• Detects and terminates VT/VF
• Primary or secondary prevention

CRT (Cardiac Resynchronization Therapy)

• Heart failure + left bundle branch block
• Provides synchronized contraction
• As CRT-P or CRT-D

Electrical Cardioversion

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• Correcting rhythm with electrical shock
• Used in AF and flutter
• Performed under anesthesia
• Planned or emergency

When to See a Doctor

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Consult a cardiologist if you experience:

• Recurrent palpitation episodes
• Fainting or near-fainting
• Palpitations with shortness of breath or chest pain
• If you feel an irregular pulse
• If there’s a family history of sudden death
• Known heart disease with new arrhythmias

Arrhythmia Prevention

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You can reduce arrhythmia risk by controlling risk factors:

• Keep your blood pressure under control
• Treat your heart conditions
• Maintain a healthy weight
• Exercise regularly
• Practice stress management
• Limit alcohol and caffeine consumption
• Avoid smoking

Frequently Asked Questions (FAQ)

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Schedule an Appointment

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If you’re experiencing arrhythmia symptoms or have arrhythmia risk factors, you can schedule an appointment for comprehensive cardiac evaluation.