Electric/Conduction Disorders

Electrical/Conduction Disorders of the Heart

The heart's electrical system controls the rate and rhythm of heartbeats. Electrical or conduction disorders, also known as arrhythmias, occur when there is a disruption in the heart's normal electrical pathways. These disorders can cause irregular heart rhythms, leading to symptoms such as palpitations, dizziness, fainting, and in severe cases, sudden cardiac arrest.

The heart has a natural pacemaker called the sinoatrial (SA) node, located in the right atrium. It generates electrical signals that travel through the heart:

SA Node (Sinoatrial Node):

Initiates the heartbeat and sets the heart rate.

AV Node (Atrioventricular Node):

Delays the signal slightly to allow the atria to contract before the ventricles.

Bundle of His & Purkinje Fibers:

Conduct the signal to the ventricles, ensuring coordinated contraction.

1. Bradyarrhythmias (Slow Heart Rate):

Sick Sinus Syndrome (SSS): A malfunction of the SA node leading to slow heartbeats or pauses.
Heart Block: A delay or complete blockage of signals traveling from the atria to the ventricles.

2. Tachyarrhythmias (Fast Heart Rate):

Atrial Fibrillation (AFib): Irregular and often rapid heartbeat originating in the atria.
Supraventricular Tachycardia (SVT): Fast heart rhythms originating above the ventricles.
Ventricular Tachycardia (VT): A fast and potentially dangerous rhythm originating from the ventricles.
Ventricular Fibrillation (VFib): A life-threatening arrhythmia that prevents the heart from effectively pumping blood.

3. Conduction Delays and Blocks

First-Degree AV Block: A mild delay in the electrical signal between the atria and ventricles.
Second-Degree AV Block: Partial blocking of signals.
Third-Degree AV Block (Complete Heart Block): Full blockage of electrical signals; requires a pacemaker.

Causes of Electrical/Conduction Disorders

Heart disease (coronary artery disease, heart attack)

High blood pressure

Electrolyte imbalances (such as low potassium or magnesium)

Congenital heart defects

Thyroid disorders (hyperthyroidism or hypothyroidism)

Certain medications (such as beta-blockers, digoxin)

Alcohol and drug use

Symptoms to Watch For

Palpitations or irregular heartbeats

Dizziness or lightheadedness

Fainting or near-fainting

Fatigue

Shortness of breath

Chest pain

Diagnosis

Electrocardiogram (ECG/EKG):

Basic test to assess heart rhythm.

Holter Monitor:

Portable ECG that records the heart’s electrical activity for 24-48 hours.

Event Monitor:

Records electrical activity when symptoms occur.

Electrophysiology Study (EPS):

Specialized study to assess electrical activity.

Lifestyle Modifications:

Avoid excessive caffeine, alcohol, and stress.

Medications:

Beta-blockers, antiarrhythmics, anticoagulants (if needed for AFib).

Pacemakers:

Used for bradyarrhythmias and heart block.

Implantable Cardioverter-Defibrillator (ICD):

Prevents sudden cardiac arrest in patients at risk.

Ablation Therapy:

Destroys abnormal electrical pathways.

Conclusion

Electrical/conduction disorders of the heart can range from harmless to life-threatening conditions. Early detection and appropriate management are crucial to prevent complications. If you have symptoms, consult a cardiologist for evaluation.

Information resources recommended

1. American Heart Association Guidelines on Arrhythmias

https://www.heart.org/en/health-topics/arrhythmia

https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193

https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia

https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549

https://pubmed.ncbi.nlm.nih.gov/16949478/

2. European Society of Cardiology Guidelines on the Management of Arrhythmias

https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death

https://academic.oup.com/eurheartj/article/43/40/3997/6675633

https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia

https://pubmed.ncbi.nlm.nih.gov/26320108/

https://www.ahajournals.org/doi/10.1161/01.cir.0000091380.04100.84

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