Daisychick: The pericardium is the "sac" covering the heart that prevent friction when it beats.
Normally, Pericarditis is bacterial, and the swelling causes pressure when the heart beats, leading to discomfort, nausea and dizziness. I had a few patients have some urinary problems with it as well. Several has respiratory issues.......wheezing, shortness of breath, pain on inhaling.
Untreated, it is a serious and dangerous condition. But with treatment, antibiotics, some sort of anti-inflamatory (possibly steroids) and at times, a diuretic, recovery is usually quick and without incident.
What that means Em........A cardiac infection sounds horrible, but try not to worry too much.
I hope that they told him to be sure to drink his fluids, and to restrict his salt intake. If he is on a diuretic (water pill) have him eat a bannana each day to help keep that potassium up. ALso, it will help his dizziness and discomfort if he doesnt lay flat on his back.

for both of you. I know that was pretty scary.