Differential Diagnosis for Acute Coronary Syndrome

Life-Threatening Conditions Requiring Immediate Exclusion

The European Society of Cardiology recommends that aortic dissection must be immediately considered and excluded before initiating any anticoagulation or thrombolytic therapy in patients presenting with symptoms suggestive of ACS, particularly those with hypertension, atherosclerosis, and prior cardiovascular surgery, as these treatments can be catastrophic if dissection is present 1, 2
Aortic dissection is the most critical differential diagnosis because misdiagnosis can lead to fatal outcomes if thrombolytic therapy is administered, with the typical patient being a male in his 60s with hypertension 1, 2
Pain characteristics differ between dissection and MI, with dissection pain being abrupt with maximum intensity at onset, whereas MI pain builds gradually 1, 2
Proximal (Type A) dissections cause retrosternal pain, while distal dissections cause interscapular/back pain, and up to 20% of patients present with syncope without typical pain 1, 3
The American College of Cardiology recommends checking for pulse deficits, blood pressure differential between arms, and new aortic regurgitation murmur to aid in the diagnosis of aortic dissection 4, 3

Pericarditis presents with pain that changes with inspiration and position, unlike ACS, and is characterized by diffuse concave upward ST elevation and PR depression on ECG, with a pericardial friction rub present in only one-third of patients 7
Expanding aortic aneurysm should be considered in patients with known atherosclerosis and hypertension, and may present with chest, back, or abdominal pain depending on location 1, 5

Musculoskeletal pain is characterized by pain reproducible with palpation of the chest wall, and varies with breathing or position, making ACS less likely but not excluding it 5
Gastrointestinal causes, such as cholecystitis and esophageal spasm, can mimic cardiac pain but typically have distinct characteristics, such as right upper quadrant pain and pain related to swallowing 1, 8
Pulmonary causes, such as pleurisy and pneumothorax, can present with sharp, pleuritic chest pain and sudden onset dyspnea, respectively 1, 5

The American Heart Association recommends obtaining a 12-lead ECG within 10 minutes of presentation, measuring blood pressure in both arms, and assessing for pulse deficits in all extremities to aid in the diagnosis of ACS and aortic dissection 8, 4, 3
CT angiography is the diagnostic test of choice for suspected aortic dissection, with 100% sensitivity, while transthoracic echocardiography has only 60-80% sensitivity for Type A dissection 4, 6
Transesophageal echocardiography has 98-100% sensitivity but may be dangerous in unstable patients, and should be used with caution 7, 6

The European Society of Cardiology recommends never administering thrombolytics or anticoagulation until dissection is excluded in patients with risk factors, and avoiding reliance on "classic tearing pain" description, as only 51-64% of patients describe pain as sharp or stabbing 2, 3
A normal chest X-ray does not exclude dissection, and D-dimer >0.5 µg/mL has high sensitivity for dissection but should not be used alone to rule it out 3, 2