Understanding Cardiac Rhythms

Introduction

The heart's rhythm is controlled by an electrical conduction system that ensures the heart pumps blood efficiently. Abnormalities in this rhythm can lead to various health issues, ranging from benign to life-threatening conditions.

Normal Cardiac Rhythm

The normal heart rhythm, called sinus rhythm, originates in the sinoatrial (SA) node, the heart's natural pacemaker. It typically maintains a rate of 60–100 beats per minute in a resting adult.

Common Abnormal Cardiac Rhythms

There are several types of abnormal heart rhythms (arrhythmias), including:

1. Tachyarrhythmias (Fast Heart Rhythms)

• Atrial Fibrillation (AF): The most common arrhythmia, where the upper chambers of the heart quiver instead of contracting properly.
• Supraventricular Tachycardia (SVT): A broad group of fast rhythms originating above the ventricles.
• Ventricular Tachycardia (VT): A fast and potentially dangerous rhythm from the ventricles.
• Ventricular Fibrillation (VF): A chaotic, life-threatening rhythm that requires immediate intervention.

2. Bradyarrhythmias (Slow Heart Rhythms)

• Sinus Bradycardia: A slow heart rate, often seen in athletes but can also indicate a conduction problem.
• Heart Block: A delay or interruption in the conduction pathway, categorized into first-degree, second-degree, and third-degree (complete) heart block.

Symptoms and Diagnosis

Arrhythmias can cause symptoms such as: - Palpitations - Dizziness - Fatigue - Shortness of breath - Chest pain - Fainting (syncope)

Diagnosis is typically made using: - Electrocardiogram (ECG/EKG) - Holter monitoring (24-48 hours of ECG recording) - Echocardiogram - Electrophysiological study

Treatment Options

• Lifestyle Modification: Reducing caffeine, alcohol, and stress; maintaining a healthy diet
• Medications: Beta-blockers, calcium channel blockers, antiarrhythmic drugs
• Procedural Interventions:
  • Pacemaker (for slow rhythms)
  • Cardioversion (for AF and some tachycardias)
  • Catheter Ablation (to destroy faulty electrical pathways permanently)
  • Implantable Cardioverter Defibrillator (ICD) (for ventricular arrhythmias)

Conclusion

Proper diagnosis and management of cardiac rhythms are essential to prevent complications like stroke, heart failure, and sudden cardiac arrest. If you experience symptoms, seek medical advice promptly.

Source recommendations

1. American Heart Association – Guidelines for Management of Arrhythmias

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
2. https://www.heart.org/en/health-topics/arrhythmia
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
4. https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia
5. https://pubmed.ncbi.nlm.nih.gov/16949478/

2. European Society of Cardiology – Guidelines on Cardiac Rhythm Disorders

1. https://www.escardio.org/
2. https://academic.oup.com/eurheartj/article/34/29/2281/401445
3. https://www.escardio.org/static-file/Escardio/Guidelines/Documents/ehaa612.pdf
4. https://www.hrsonline.org/guidance/clinical-resources
5. https://pubmed.ncbi.nlm.nih.gov/26320108/