Helpful clues to distinguishing pericarditis vs. STEMI Pericarditis: PR depression in multiple leads, PR elevation > 2 mm in aVR; friction rub (specific though not sensitive) Remember that PR depression mainly only shows up in viral pericarditis, not other types STEMI: horizontal or convex upwards (like a tombstone) STE, ST depression in any lead aside from aVR and V1, STE in III > II