Is pericarditis considered a chronic condition?

Pericarditis. No, pericarditis is generally not considered to be a chronic condition but it can recur in about 15-30% of people who have so-called acute, idiopathic (unknown cause) pericarditis that previously responded to treatment.
Not always. Most cases of pericarditis are acute episodes and short lasting. Occasionally pateints develop chronic inflamation and that constitutes chronic pericarditis.