Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Tissue hypoperfusion: depressed mental status, cool extremities, urine output < 30 mL/hour Hypotension: systolic blood pressure < 90 mm Hg Cardiac index < 2.2 L/min/m2 Pulmonary artery wedge pressure > 15 mm Hg +++ GENERAL CONSIDERATIONS ++ Causes and contributors: right or left ventricular failure, mechanical complications of acute myocardial infarction (MI) ventricular septal rupture, papillary muscle rupture or dysfunction, and free wall rupture; cardiomyopathies: valve disease; arrhythmias; toxic substances; posttraumatic and abnormalities of diastolic filling Shock resulting from an acute MI typically involves ≥ 40% of the left ventricular myocardium Most patients dying of cardiogenic shock have severe 3-vessel coronary artery disease +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ History of chest pain associated with MI within hours or up to a week Cardiac arrest associated with an acute MI Shortness of breath or acute respiratory distress Syncope Palpitations Nausea, vomiting Diaphoresis Obtundation and lethargy +++ PHYSICAL EXAM FINDINGS ++ Systolic blood < 90 mm Hg Tachycardia Tachypnea Confusion, lethargy, or obtundation Pulmonary rales Jugular venous distention Displaced and diffuse apical impulse Muffled heart sounds in the presence of a pericardial effusion or cardiac tamponade S3 and S4 Short, systolic murmur in patients with acute, severe mitral regurgitation – Systolic murmur and associated parasternal thrill may indicate a ventricular septal rupture Hepatomegaly; pulsatile liver with severe tricuspid regurgitation Ascites in cases of longstanding right heart failure Peripheral edema Peripheral pulses are rapid and faint Mottled extremities Cool, ashen, or cyanotic skin +++ DIFFERENTIAL DIAGNOSIS ++ Septic shock Hypovolemia Extracardiac obstructive: pulmonary embolism, pericardial tamponade +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ Troponin Electrolytes, blood urea nitrogen, creatinine, and serum lactate CBC Bilirubin, alanine transaminase, aspartate transaminase, lactate dehydrogenase, partial thromboplastin time, prothrombin time Arterial blood gases +++ ELECTROCARDIOGRAPHY ++ Sinus tachycardia or atrial tachyarrhythmias Q waves may indicate prior MI ST and T waves suggestive of an acute MI +++ IMAGING STUDIES ++ Chest x-ray: – Cardiomegaly and pulmonary vascular congestion or edema – Heart size may be normal in patients with a first infarction – Pulmonary congestion may be less prominent or absent in patients with predominant right ventricular failure or hypovolemia Echocardiography: – Provides assessment of left and right ventricular size and function, global and segmental wall motion, valvular function (stenosis or regurgitation), right ventricular systolic pressures, and detection of ventricular septal shunts and pericardial fluid +++ DIAGNOSTIC PROCEDURES ++ Right heart catheterization (generally useful to exclude other causes of shock); hemodynamic indicators of cardiogenic shock are pulmonary capillary wedge pressure > 15 mm Hg and a cardiac index < 2.2 ... Your Access profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. 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 Username Error: Please enter User Name Password Error: Please enter Password Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free a profile for additional features.