👉 Arrhythmia is a medical condition that occurs when there is an abnormal electrical activity of the heart. This can happen in any part of the heart, but it's most common in the left atrium (left side of the heart) and the ventricles (the two chambers of the heart). It can cause irregular heartbeats or fast heartbeats that are too high in pitch. The symptoms of arrhythmia include chest pain, shortness of breath, dizziness, nausea,