Hi Annie, My cardiologist “suspects” that I suffer from coronary artery spasm. Had a severe heart attack 34 years ago while playing basketball. Subsequent catherization found no blockage. Over the years stress tests have led to the belief that I have blockage and subsequent cath have always found no blockage. Dr. feels the most likely cause is arterial spasm, but evidently there is no way to prove it. Rarely do AI have angina. May use a nitro pill once or twice yearly. It was more frequent in the years after the heart attack. Recently have experienced arrithmia and a-fib. Just had a CRT-Defib device implanted.