SOB

[ed34]

I am confused and hope you can explain in laymans terms how this occurs...
If a heart is not enlarged and has a top of the range EF, say 70%, and there are no lung problems or blockages in the pulmonary vessels, how can atherosclerosis entice faster respiration rates, i.e. the feeling of being short of breath?
I thought the major component to respiration rate was the acidity of blood, yet if you develop a blockage in a coronary artery, it somehow signals the body that there's a problem with oxygen levels and you need to breathe faster. What is the mechanism for this communication between the heart and the respiratory system? For example, does cardiac muscle release an enzyme which signals the lack of oxygen to respiratory control? I have searched high and low but cannot seem to find this important link for such a relationship.
Many thanks indeed
Ed

[ed34]

Oh and I would like to say a very big thank you for your time on this forum helping me and so many other people. It's very good of you.

[ed34]

Sort of. I've been in a situation more than once where my heart has shown ischemia during a stress echo. However, my LVEF has been 70%. I therefore assumed that my heart was working with normal sufficiency, even though ischemia was present. I felt short of breath with slight exertion, but couldn't understand why if my heart is pumping a normal volume of blood. What you say makes sense, because breathing faster (if I had normal oxygen levels) would make me quite dizzy and this was never the case. Perhaps the 70% stated was during rest but the LVEF was lower during stress/ischemia and not reported.

[CCF HeartMD3]

ed34,

There are many reasons that one can feel short of breath. The main reasons include heart failure, angina (lack of sufficient blood flow to the heart), lung problems, and anemia. Your question specifically seems to asking for the mechanism of how coronary blockages contribute to feelings of breathlessness.

The heart is a muscle which requires blood much like other muscles in your body. The heart is supplied by the coronary arteries which can over time develop blockages. When these blockages are mild they do not result in any significant limitation in blood flow. Over time these blockages can progress to the point where they cause you to feel short of breath or have chest discomfort.

When insufficient amounts of oxygen are delivered to the heart (known as ischemia), the function of the heart then decreases. There is now decreased blood flow to the rest of the body (which lowers the amount of oxygen delivered). The body attempts to compensate for this by breathing harder - hence the feeling of being short of breath. In addition, if the ischemia is bad enough blood flow can then back into the lungs which also make one feel short of breath. It is a fairly complicated process with much more detail and nuance than offered here but I hope that this helps.