What condition is characterized by an abnormal heart rhythm?

Arrhythmia is the condition characterized by an abnormal heart rhythm. This term encompasses a wide range of irregular heartbeats, which can be either too fast, too slow, or erratic. A person with arrhythmia may experience palpitations, dizziness, fatigue, or even more severe symptoms depending on the type and severity of the arrhythmia.

Hypertension refers to high blood pressure and does not directly relate to the rhythm of the heart. Tachycardia specifically describes a type of arrhythmia where the heart rate is abnormally high; while it is a form of arrhythmia, it does not represent the broader category. Dyspnea is a term for difficulty breathing and also does not connect directly to heart rhythm abnormalities. Therefore, the most appropriate choice that encompasses any irregularities in heart rhythm is arrhythmia.