Arrhythmias are classified based on their origin (atrial or ventricular) and their effect on heart rate (fast, slow, or irregular). Here’s a breakdown of the different types of arrhythmias and their specific characteristics:
1. Bradycardias (Slow Heart Rate)
- Sinus Bradycardia: The heart rate is consistently below 60 beats per minute. It can be normal in physically fit individuals but problematic if it causes symptoms like dizziness or fainting.
- Heart Block (Atrioventricular Block): Delays or blocks the electrical signal from passing from the atria to the ventricles. Severity can vary; higher-degree blocks might require a pacemaker.
2. Tachycardias (Fast Heart Rate)
- Sinus Tachycardia: A normal increase in heart rate that happens during exercise or stress. It becomes abnormal if persistent without a reason, typically over 100 beats per minute.
- Atrial Fibrillation (AFib): The most common type of serious arrhythmia, characterized by a very rapid, irregular heartbeat caused by chaotic electrical signals in the upper chambers (atria). It increases the risk of stroke and heart failure.
- Atrial Flutter: Similar to AFib but with more organized electrical abnormalities. It often leads to a fast but regular rhythm in the atria.
- Supraventricular Tachycardia (SVT): A rapid heartbeat that begins in the upper chambers of the heart. It can cause palpitations, dizziness, or chest pain but is generally not life-threatening.
- Ventricular Tachycardia (VT): A fast, regular beating that originates in the lower chambers (ventricles) and can be life-threatening. It may lead to ventricular fibrillation if not treated quickly.
- Ventricular Fibrillation (VFib): A severely abnormal heart rhythm marked by rapid, erratic electrical impulses in the ventricles. It is an emergency situation leading to cardiac arrest if not immediately corrected.
- Premature Atrial Contractions (PACs): Early beats that originate in the atria. They are common and often harmless.
- Premature Ventricular Contractions (PVCs): Early beats that originate in the ventricles. They can be benign in healthy individuals but may be more serious in those with heart disease.
- Sick Sinus Syndrome: The sinus node (the heart’s natural pacemaker) does not function properly, leading to alternating slow and fast heart rates.
- Long QT Syndrome: A disorder of the heart’s electrical system that can cause sudden, uncontrollable, dangerous arrhythmias in response to exercise or stress. It’s often genetic and can lead to sudden death.
Each type of arrhythmia has its own set of implications and potential complications, requiring specific diagnostic and treatment approaches. Understanding these types allows for better management and more targeted treatments, such as medications, catheter ablation, or implantable devices like pacemakers and defibrillators.