How far does an ECG go towards diagnosing Heart failure, does a normal ECG mean it is not present? I have been having problems sleeping, an uneasy feeling accompanied by bouts of chest tightness and increased heart rate when i try to sleep. I went to my GP who said the symptoms were stress related as I had chest pains and a pressure headache which have now ceased. Recently I have developed a build up of mucus that is lining the back of my mouth and throat. I am not wheezing and do not have a cough, there are no apparent areas of swelling on my body. When i physically exert myself i have no pain, I have a slight noticable increase in heart rate, more than before but thats it. I have had an ECG which was fine, is an ECG enough to diagnose heart failure on its own? any ideas about what else it could be?