Experiencing a fast heart rate and palpitations can be unsettling, but please stay calm. To safely control this, you need a professional medical evaluation, including an ECG, to find the exact cause. Depending on your diagnosis, a doctor may prescribe heart-rate-controlling medications such as beta-blockers (like metoprolol or propranolol) or calcium channel blockers (like diltiazem). It is crucial not to take any of these medications without a prescription, as the wrong treatment can be harmful. Please consult a healthcare professional promptly to get an accurate diagnosis, and seek immediate emergency care if you experience chest pain, shortness of breath, or dizziness.