You should not be concerned. The opinion of your cardiologist that you don t have heart problem is very likely to be right. You may be suffering from Panic Disorder, where one gets sudden episodes of intense anxiety last from a few minutes to a couple of hours. The patient often feels something is going to happen to him or he is going to lose control. The patient runs to emergency room of hospital or cardiologists. Panic Disorder is a disorder of nervous system that has psychological manifestations. Since your cardiologist has done the necessary tests and given you all clear , there is not need to go to a cardiologist at this stage. You should consult a psychiatrist. He/she will evaluate you properly, counsel you about the nature of your condition and prescribe medicines if necessary. He/she may also suggest a therapy such a cognitive behavioral therapy. Combination of medicines and therapy gives best results.