Rhythm disturbance is a medical term that refers to an irregular heartbeat or arrhythmia. Other synonyms for rhythm disturbance include heartbeat irregularity, heart arrhythmia, heart palpitations, cardiac dysrhythmia, and abnormal heart rhythm. There are different types of rhythm disturbances that may occur, including tachycardia (fast heart rate), bradycardia (slow heart rate), atrial fibrillation (irregular heartbeat originating from the upper chambers of the heart), and ventricular fibrillation (irregular heartbeat originating from the lower chambers of the heart). Some possible causes of rhythm disturbances include heart disease, high blood pressure, stress, alcohol, caffeine, and drug use. If you experience any symptoms of rhythm disturbance, including chest discomfort, shortness of breath, or dizziness, it is important to seek medical attention immediately.