A sensation of the heart stopping and restarting (palpitations) is a common complaint. Often these episodes are brief and harmless; they can be related to stress, caffeine, poor sleep, or anxiety. If you have dizziness, shortness of breath, fainting, or severe chest pain seek immediate medical attention. If those red-flag symptoms are absent but palpitations are frequent, prolonged, or distressing, start with a visit to your Family Medicine or Internal Medicine doctor; they can arrange further tests or refer you to Cardiology. Simple measures such as resting, staying hydrated, improving sleep and reducing triggers (for example caffeine or intense stress) may help, but see a health professional for a definitive assessment.