Hello, Thank you for your query. You seem to have described palpitations (racing heart that is felt like thuds). These are usually associated with anxiety. Sometimes, though, it could be associated with heart pathology, especially when accompanied by tingling, numbness, pain to left arm, jaw, neck & back. I would first like to rule out cardiovascular problems & cervical spondylosis. I would: - elicit a detailed history of your personal, medical & family medical history. (diabetes, hypertension, heart disease, high cholesterol, thyroid hormone imbalances, kidney disease, smoking alcohol abuse) -do a complete physical exam & basic blood investigation (complete blood count, ESR, glucose panel, lipid profile, kidney & liver function test and thyroid hormone levels) -get an electrocardiogram, echocardiogram, chest & cervical spine x-rays, stress test & angiography if indicated. Based on the above results I can assess the for atherosclerosis, ischemia, heart rhythm & function abnormalities, pericardial effusion & cervical spondylosis (narrowing of the space between the vertebrae in the neck that causes nerve impingement resulting in tingling /numbness /pain arms). I would then formulate a treatment plan. I suggest that you see a physician right away to rule out heart problems as symptoms of this can vary between subtle to severe and can go from ok to worse in minutes. I don t mean for you to panic but to caution. Better safe than sorry. Hope this helps. Wish you good health. Please get back to us for further clarification.