Irregular heartbeat can be a serious medical condition, and it may be referred to using different synonyms. Some of the commonly used synonyms include arrhythmia, cardiac dysrhythmia, and atrial fibrillation. These terms describe a condition where the heart beats irregularly, either too fast or too slowly, and can cause a range of symptoms, including dizziness, fatigue, and chest pain. Other terms used to describe irregular heartbeat include heart palpitations, heart rhythm disorders, and tachycardia. If you experience any of these symptoms, it's important to seek medical attention promptly to receive an accurate diagnosis and appropriate treatment to avoid complications.