Hi, Definitely, most of the heart attacks are due to clogged arteries, as a result of plaque formation or plaque rupture. However, in some cases, the heart attack can be even without clogged arteries. This type of attacks are known as MINOCA (Myocardial infarction without obstructive coronary arteries). Approximately in 6% of the cases such type of heart attacks occur. Usually, the symptoms with this type of heart attacks are milder than the attacks with clogged arteries. Morbidity and mortality is also less in such types of heart attacks. This type of attacks may be due to increased demand or less supply of oxygen to the heart muscles, resulting in death of cardiac cells and hence, resulting in heart attack. Anemia, bleeding, severe exercises, any reason which reduces the pumping power of heart may cause heart attacks without clogging of arteries. Also, in some viral infections / fever, the death of cardiac cells may be there without clogged arteries, but directly as a result of disease / infection resulting in heart attack. In your case, as you have already undergone with most of the tests, hence most of the causes of MINOCA should have been already ruled out. Also, as already described, even if such type of attacks occur, morbidity or mortility is much less. Therefore, in all likelihood, you are just having a phobia for this. It may be a part of general anxiety disorder in your case. If the problem persists, then you are advised to see a psychiatrist and treated accordingly. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Satnarain Bansal, General & Family Physician