Heart rhythm disorders, also known as arrhythmias, occur when the heart beats too fast (tachycardia), too slow (bradycardia), or irregularly due to electrical signal disturbances. Common types include atrial fibrillation (AFib), atrial flutter, supraventricular tachycardia (SVT), ventricular tachycardia, and ventricular fibrillation, which can be life-threatening. Bradycardia-related conditions include sick sinus syndrome and heart block. Arrhythmias can be caused by heart disease, high blood pressure, electrolyte imbalances, thyroid disorders, excessive caffeine or alcohol, stress, certain medications, and congenital heart conditions