Acute Aortic Disease.. - Index of

Putting It All Together: Symptoms, Signs, and Images 73
Figure 2 Pulse deficits as a clinical predictor of mortality in acute aortic dissection. Source:
From Ref. 31.
expected diastolic murmur of aortic regurgitation is often brief and hard to hear,
and is only documented in less than half of patients with acute Type A dissection.
Cardiac tamponade may be suspected at the bedside and rapidly confirmed
with bedside echocardiography (2,13,24,32). If cardiac tamponade occurs in the
setting of acute aortic dissection, bedside pericardiocentesis is relatively contraindicated
and should be deferred until emergency cardiac surgery can be
performed (33).
ELECTROCARDIOGRAM AND CHEST X-RAY
A 12-lead electrocardiogram (ECG) should be obtained to document the presence
of ischemia in every patient presenting with chest pain or suspected aortic
dissection (5,30,34). The ECG may imply useful prognostic information, as observational
studies in patients with acute dissection have found that an abnormal
ECG is an independent predictor of in-hospital death (2). A challenging dilemma
exists in differentiating acute coronary syndrome from acute aortic syndrome,
as patients with both conditions will often carry overlapping risk factors and will
have similar clinical presentations. Most importantly, establishing the correct diagnosis
is essential, as treatment for acute coronary syndrome (anticoagulation and
cardiac catheterization) may have catastrophic consequences in the presence of
aortic dissection (34). In this setting, a normal ECG may persuade the clinician to
pursue the diagnosis of aortic dissection over acute coronary syndrome. However,
nonspecific repolarization abnormalities (ST and T-wave segments) are the most
common finding in patients with acute dissection. Also, a small percentage of