Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (47 page)

   Diagnosis

   Exogenous catecholamine diagnosis is made via history or toxicology screening.

   Pheochromocytoma.

   Stress-induced cardiomyopathy: Four necessary criteria are required for diagnosis by the Mayo Clinic criteria—(1) transient hypokinesis, akinesis, or dyskinesis of the left ventricular midsegment with or without apical involvement most often in the setting of a stressor (physical or emotional). Wall motion abnormalities usually extend beyond the distribution of a single coronary artery; (2) absence of obstructive coronary disease or plaque rupture; (3) new ECG changes (ST-elevation or T-wave inversion) or modest troponin elevation; (4) absence of pheochromocytoma or myocarditis.

   If ST-segment elevations are present or the clinical presentation is consistent with high-risk ACS, confirmation of a diagnosis should not delay decision to proceed to mechanical revascularization. A lack of angiographic findings of a “culprit” stenosis will suggest the diagnosis along with wall motion abnormalities seen by ventricular imaging.

   Laboratory Findings

   Positive tox screen for intoxication syndromes (see pheochromocytoma).

   Serial cardiac troponins may help differentiate between ACS.

   At present, stress-induced cardiomyopathy is a diagnosis of exclusion from overlapping clinical syndromes.

Suggested Readings

Simpson RW, Edwards WD. Pathogenesis of cocaine-induced ischemic heart disease.
Arch Pathol Lab Med.
1986;110:479–484.

Wittstein I, Thiemann D, et al. Neurohumoral features of myocardial stunning due to sudden emotional stress.
N Engl J Med.
2005;325:539–548.

CHEST PAIN: NONCARDIAC ETIOLOGY

ACUTE AORTIC SYNDROMES

   Definition

   Acute aortic syndromes encompass the related entities of aortic dissection, intramural aortic hematoma, and penetrating aortic ulcer. As these conditions may be imminently life threatening, a high clinical suspicion must be present to ensure prompt diagnosis and treatment.

   The Stanford model of classification is the most widely used and is based on anatomical location. Type A is involvement of the ascending aorta, and type B is a dissection not involving the ascending aorta.