Which would NOT be a clinical finding that would indicate a patient has pericarditis?

Flat neck veins would NOT be a clinical finding that indicates a patient has pericarditis. In patients with pericarditis, you would typically expect to see signs related to fluid accumulation or inflammation around the heart, such as a pericardial friction rub, muffled or distant heart sounds (which may indicate cardiac tamponade), and dyspnea. Elevation of the neck veins (jugular venous distention) could occur in certain situations, like in cases of cardiac tamponade, but flat neck veins are generally not associated with pericarditis.