What is the exact physiological cause of dyspnea associated with acute MI?

is it from diastolic dysfunction causing backflow of blood into the pulmonary vasculature or from another cause. Most references do not pin the cause on a good physiologic reason. Any help would be greatly appreciated

An acute MI does cause diastolic dysfunction. This is evidenced by an increased left ventricular end diastolic pressure when measured at cardiac catheterization. The left ventricular end diastolic pressure is reflected back into the left atrium, as higher atrial pressures are then required to fill the left ventricle. The left atrial pressure is then reflected to the pulmonary veins and capillaries. A high pressure in this area, typically above 21 mm Hg, results in pulmonary edema, exacerabting the dyspnea. The elevated pressure in the pulmonary system is documented by placement of a right heart (Swan Ganz) catheter.

An MI can also produce dyspnea due to an acute mechnaical complication, such as sudden severe mitral regurgitation. This may be due to rupture of the chordae tendinae that help the valve close. Although extremely rare, such a mechnaical complication will result in severe dyspnea and the need for mechnaical ventilation.

Hope this helps explain some underlying physiology.

That is exactly what it's from. The damaged heart can't pump the blood like it's supposed to, therefore there is a backup and the blood has nowhere to go but back into the lungs vascular system (pulmonary edema)

try