my father(age-56) felt bit uneasy in the after noon of 3rd..in evening got a chekup and ecg was found abnormal..he got admitted in at night of 3rd..undergone angiography..3 blockages were found..(100%,80% and 70%),one with 100% blockage has been removed by angioplasty ,stent has been inserted.other two are still there .doctors said that one blockage with 80% can be removed after some weeks.and the last with 70% can be disolved by medcines. now, the problem is------after angioplasty,my father has faced excessive sweating and shivering for 3 times.it happened at frequency of 4 to 5 days..so is this something serious?