<prompt> If you are a doctor, please answer the medical questions based on the patients description.A few times when I have bent down to do up my shoe my heart all of a sudden starts beating out of contro and i get dizzy and sometimes it will slow down on its own, 2 times i had to go to emerge and the gave me a needle of something to get it back to normal. What is it?  <response>: Hello, I would explain that your symptoms could be related to cardiac arrhythmia. Gastroesophageal reflux cannot be excluded either. Coming to this point, I would recommend consulting with your attending physician for a physical exam and some tests: - a resting ECG and cardiac ultrasound- a chest X-ray study-complete blood count for anemia-thyroid hormone levels for thyroid gland dysfunction- blood electrolytes for possible imbalance. An ambulatory 24-48 hours ECG monitoring would help examine your heart rhythm trends for a prolonged time and exclude possible cardiac arrhythmia. Hope I have answered your query. Let me know if I can assist you further. 