Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 145

In the reperfusion era, inflammatory pericarditis occurs in ~5% of STEMIs, usually large or anterior STEMIs (it was more common in the pre-reperfusion era, ~10–20%). Less commonly, it may occur in large NSTEMIs. The incidence is higher if only pericarditic chest pain is used to define post-infarction pericarditis, without mandating a rub.¹⁶² On the other hand, asymptomatic rubs are also common in the first 48 hours of MI. Pericarditis, including asymptomatic rub, correlates with a larger MI size, and thus carries a worse prognosis despite being innocuous per se.

A minimal or small pericardial effusion is seen in up to a third of patients with MI.¹⁶³ Pericarditis and pericardial effusion do not neces- sarily coincide. Over half of pericarditis cases are not associated with any effusion; similarly, half of pericardial effusions are not inflammatory (no rub), and rather result from pump failure and transudation.¹⁶³

1 Diagnosis – Pericarditis develops in the first few days of MI, most commonly the first or second day, and usually lasts a few days only. The pain is typically pleuritic, and radiation to the trapezius is characteristic. A fleeting rub may be heard. On ECG, a pattern of diffuse pericarditis with diffuse ST elevation is rare (<20%);¹⁶² rather, pericarditis is localized to the infarcted area with ECG findings of localized ST elevation. The latter may simulate reinfarction or may be overshadowed by the pre-existing ST elevation. The persistence of upright T waves or the reversal from inverted T waves to upright T waves very early after MI is 100% sensitive for the diagnosis of pericarditis, but may also be seen with ischemia (normally, inverted T waves are seen a few hours after MI onset, and persist several days at least).¹⁶⁴

2 Treatment – NSAIDs should not be used post-MI because of the risk of adverse LV remodeling and free wall rupture. High-dose aspirin (325–650 mg Q 6–8 h) may be used; alternatively, acetaminophen or colchicine may be used for this transient process.The risk of hemorrhagic transformation of acute post-MI pericarditis is theoretical and very rarely reported. Thus, pericarditis should not alter the antiplatelet regimen and anticoagulation may be continued in patients who need it, with close monitoring. However, in the presence of a moderate or large effusion, anticoagulants are preferably discontinued (antiplatelet agents are usually continued).