Position and Size of Heart
As the uterus enlarges and the diaphragm becomes elevated, the heart is displaced upward and somewhat to the left with rotation on its long axis, so that the apex beat is moved laterally. Cardiac capacity increases by 70-80mL; this may be due to increased volume or hyperthophy of cardiac muscle.The size of the heart appears to increase by about 12%Cardiac Output
Cardiac output increases approximately 40% during pregnancy, reaching its maximum at 20-24 week’s gestation and continuing at this level until term. The increase in output can be as much as1,5L/min over the non pregnant level. Cardiac output is very sensitive to changes in body position. This sensitivity increases with lengthening gestation, presumably because the uterus impinges upon the inferior vena cava, thereby decreasing blood return to the heart. The increase in plasma volume (40-50%) is relatively greater than that of red cell mass (20-30%) resulting in hemodilution and a decrease in hemoglobin concentration
I've been getting these ( not really episodes, but ) brief moments in the day when I feel like my heart's beating too fast, and it makes me uncomfortable for a little while. But it doesn't make me feel faint or anything like that. It just makes me feel like I've run up a flight of stairs. And then it goes away after a couple of minutes.
It's also strange, but I wouldn't trade this for anything in the world :)