Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Acute myocardial infarction (MI) documented Normal or near-normal coronary angiography +++ GENERAL CONSIDERATIONS ++ Up to 10% of all patients and 25% of patients < 35 years do not have coronary atherosclerosis on angiography after an MI More common in Asian patients Coronary artery spasm occurs at sites of subcritical stenosis and in completely normal arteries on angiography In young patients, cocaine may induce vasospasm and MI Coronary embolism with subsequent recanalization occasionally may be a cause of acute MI Rarely, markedly elevated myocardial oxygen demand may precipitate an MI Rarely, pseudoephedrine and ephedra cause MI with normal coronary arteries Women who take estrogens and smoke can have MI with normal coronary arteries Coagulopathies or hyperviscosity syndromes can lead to in situ coronary thrombosis Coronary supply/demand mismatch in hypertrophic cardiomyopathies can cause MI +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Chest pain similar to that in MI that lasts > 30 minutes Dyspnea Palpitations Diaphoresis during chest pain +++ PHYSICAL EXAM FINDINGS ++ S3 and S4 may occur depending on left ventricular function Bilateral pulmonary rales may occur if there is heart failure Elevated jugular venous distention may occur +++ DIFFERENTIAL DIAGNOSIS ++ Rupture of a minimal (< 50% diameter narrowing) plaque with thrombus formation and subsequent dissolution Takotsubo cardiomyopathy may mimic MI Myocarditis Arteritis Trauma +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ CBC, brain natriuretic peptide test Cardiac biomarkers such as troponin T or I +++ ELECTROCARDIOGRAPHY ++ Twelve-lead ECG may show ST elevation or marked ST depression +++ IMAGING STUDIES ++ Echocardiogram may show regional wall motion change Left ventricular function may be normal or abnormal Cardiac MRI usually shows normal myocardium but can show necrosis Cardiac MRI useful to eliminate myocarditis and hypertrophic cardiomyopathies +++ DIAGNOSTIC PROCEDURES ++ Coronary angiogram Angiogram will be normal without evidence of atherosclerosis or show minimal change not enough to account for complete cessation of blood supply Spontaneous focal spasm of coronary artery may occur Provocation tests to provoke coronary spasm no longer recommended +++ TREATMENT +++ CARDIOLOGY REFERRAL ++ All patients must be evaluated by a cardiologist +++ HOSPITALIZATION CRITERIA ++ All patients must be hospitalized initially +++ MEDICATIONS ++ Thrombolysis for suspected thrombosis or embolism Nitrates or calcium channel blockers to relieve spasm Specific therapy for or elimination of precipitating factors Secondary prevention measures as appropriate (eg, smoking cessation) Beta blockers generally avoided because of potential of unopposed alpha stimulation If coronary ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.