LV Failure
• Presentation ranges from pulmonary edema to frank cardiogenic shock
• Tx
Diuresis for pulmonary edema w/o e/o shock
↓ afterload: IV NTG or nitroprusside
Inotrope: If the above Rx’s fail, give dopamine or dobutamine
Other: For cardiogenic shock, consult cardiology. Avoid diuretics, start w/ inotropes, ↓ afterload. May need IABP. Will need revascularization ASAP (NEJM 1999;341:625).
IMI Complications (Circulation 1990;81:401; Annals 1995;123:509)
• Heart block
2° RCA involvement (supplies AV node), can develop high-degree AV
Block abruptly. Rx: Atropine/place TC pacer pads on pt & prepare for TV pacing, if necessary.
• Precordial ST ↓
DDx includes (1) anterior ischemia, (2) posterior STEMI, (3) reciprocal Δs. Obtain posterior leads to r/o posterior STEMI.
• RV infarct
P/w signs of right-sided failure: Hypotension, JVD 2° prox RCA occlusion
Obtain right-sided leads → 1 mm STE in V4R. Avoid nitrates, as these pts are preload dependent. Give dobutamine for persistently low BP (↑ contractility), consult cardiology, urgent reperfusion (NEJM1998;338:933).
Mechanical Complications
• Typically several days post-MI
• Free wall rupture
Tear occurs in the myocardial wall @ junction b/w nl/infarcted muscle, most commonly in elderly person w/ large MI. P/w PEA, ↓ BP, cardiac tamponade. Tx w/ IV fluids (preload dep.), bedside echo (? peric effusion). Consult surgery/cardiology. If +effusion & unstable → bedside pericardiocentesis. If stable → operative repair.
• Papillary muscle rupture
Occurs in small MI, IMI > AMI, p/w new murmur. Rx:
Diuretics, vasodilators, IABP, surgery consult for operative repair
• Arrhythmias
AF most common. VT/VF → r/o MI, √ lytes. Monomorphic VT w/i 48 h MI → benign. AIVR: Slow VT (HR <100), often s/p reperfusion, self-limited/benign. New 2°/3° AVB → TC pacing ± TV pacing, esp if a/w BBB. TV for new 3° AVB, new BBB + 2° AVB type II, alternating LBBB/RBBB. Consult cardiology.
• Other
LV thrombus: Anticoagulate
Ventricular aneurysm: Suspect if persistent STE post-MI. Obtain echo for Dx. Consult surgery, admit.
Pericarditis: Pericardial rub 1–4 d post-MI. ASA, NSAIDs, minimize anticoagulation.
Dressler syndrome: Inflammatory syndrome 2–10 wk post-MI. Fever, pericarditis, pleuritis. ASA, NSAIDs.