The cardiologist thinks it's acid reflux which can cause wheezing, coughing, shortness of breathe, etc; even without
having heartburn which has not been a problem for me. I have been on Nexium for 5 days now, and I feel slightly better, but was up all last night because I couldn't breathe, then around 3:30am I was fine! I have an echocardiogram shceduled for this afternoon. I'm sure it will be fine too. I've also read that anemia or hypothyroidism can cause this.