Diagnostic studies-pericardial tamponade

• ECG: ↑ HR, ↓ voltage (seen in 42%), electrical alternans (20%), ± signs of pericarditis

• CXR: ↑ cardiac silhouette (89%)

• Echocardiogram: ⊕ effusion, IVC plethora, septal shift with inspiration diastolic collapse of RA (Se 85%, Sp 80%) and/or RV (Se <80%, Sp 90%) respirophasic ∆’s in transvalvular velocities (↑ across TV & ↓ across MV w/ inspir.) postsurgical tamponade may be localized and not easily visible

Echocardiogram

• 心包積液

• 心臟在液體中擺動

• 二尖瓣 (>30%) 或三尖瓣 (>60%) 流速的呼吸變異增加

• RV 舒張早期塌陷，RA 舒張晚期塌陷（任何心室塌陷：敏感性 90%；特異性 65%）

• 吸氣時 IVC 擴張，直徑縮小不到 50%

• Cardiac cath (right heart and pericardial): elevation (15–30 mmHg) and equalization of intrapericardial and diastolic pressures (RA, RV, PCWP), blunted y descent in RA ↑ in stroke volume postpericardiocentesis = ultimate proof of tamponade if RA pressure remains high after drainage,

• Ddx: effusive-constrictive dis. (visceral pericardium constriction), myocardial. dysfxn (eg, concomitant myocarditis)