We all get palpitaions. Anxiety can cause them, it can cause a rapid pulse rate too. How old are you? Are you an anxious person? If you feel in any way ill you should talk to a doctor and have a reliable check on your blood pressure. Palpitations and a rapid pulse will not normally give rise to an enlarged heart. It is more likely to be caused by hypertension. Occasionally it s due to a tight exit valve (the aortic valve), and very rarely it is caused by an inherited disease of heart muscle. If you have high blood pressure, this means that your heart has to work harder to push blood round your body. To cope with this extra effort, your heart muscles become thicker and stiffer, which can make the heart become enlarged. An enlarged heart will not pump as well as it should, and this can cause you problems.