A septal infarct is a heart attack. The septum is the muscular wall that divides the four chambers of the heart. The lower and largest part of the septum divides the left and right ventricle. In most people this part of the septum is supplied blood by the left anterior descending (LAD) artery. I have 3 stents in mine. No one can survive a complete blockage of the LAD (no blood flow to the septum). This leads to a massive heart attack or a better term for heart attack is an MI (myocardial infarction). My cardiologist explained this to me.
You may have got this information from a computer generated analysis of your EKG. I have had many unbelievable, or astounding computer analysis of my EKGs. Yet the cardio always told me that the computer was wrong. If you have had a septal infarction that was severe enough, and the doctor confirmed this finding (EKG), I think you would have immediately been sent to the cath lab for a cardiac catheterization to determine what type of blockage, within your coronary arteries, caused this MI.
How long have you had tachycardia? Are you taking a beta blocker to slow down your heart rate? Orthopnea is a very serious condition. Especially if it was caused by an MI. You may have had tachycardia for years, but it could also have been caused by an MI. Anything that damages certain areas of the heart (the sinus nodes), can cause heart rhythm abnormalities (arrhythmias).
You need to make sure that you are prepared to call 911. Women often do not have the typical chest pain associated with an MI, I have read. They get nausea and other vague pains, cold sweats and a feeling of doom.
So please be careful!!!!!