IMI complications

• Heart block: ~20%, occurs in part because RCA typically supplies AV node

40% on present., 20% w/in 24 h, rest by 72 h; high-grade AVB can develop abruptly

Rx: atropine, epi, aminophylline (100 mg/min × 2.5 min), temp pacing wire

• RV infarct: proximal RCA occlusion → ↓ flow to RV marginals

Angiographically present in 30–50% of cases, but only ~½ clinically significant

HoTN; ↑ JVP, ⊕ Kussmaul’s; ≥1 mm STE in V4R; RA/PCWP ≥0.8; RV dysfxn on TTE

Rx: optimize preload (RA goal 10–14 mmHg; BHJ 1990;63:98); ↑ contractility (dobutamine); maintain AV synchrony (pacing as necessary); reperfusion (NEJM 1998;338:933); mechanical support (IABP or RVAD); pulmonary vasodilators (eg, inhaled NO)