Cardiogenic Shock Clinical Presentation

Updated: Jan 11, 2017
  • Author: Xiushui (Mike) Ren, MD; Chief Editor: Henry H Ooi, MD, MRCPI  more...
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Presentation

History

Cardiogenic shock is a medical emergency. A complete clinical assessment is critical to understanding the cause of the shock and to targeting therapy for correcting the cause. The presenting history will vary depending on the underlying etiology of cardiogenic shock.

Cardiogenic shock following acute myocardial infarction (MI) generally develops after admission to the hospital, though a small number of patients are in shock at presentation. Patients demonstrate clinical evidence of hypoperfusion (low cardiac output), which is manifested by sinus tachycardia, low urine output, and cool extremities. Systemic hypotension, defined as systolic blood pressure below 90 mm Hg or a decrease of 30 mm Hg in mean blood pressure, ultimately develops and further propagates tissue hypoperfusion.

Most patients who develop acute MI present with an abrupt onset of squeezing or heavy substernal chest pain; the pain may radiate to the left arm or the neck. The chest pain may be atypical, the location being epigastric or only in the neck or arm. The pain quality may be burning, sharp, or stabbing. Pain may be absent in persons with diabetes or in elderly individuals.

Patients also may report associated autonomic symptoms, including nausea, vomiting, and sweating.

A history of previous cardiac disease, use of cocaine, previous MI, or previous cardiac surgery should be obtained. A patient thought to have myocardial ischemia should be assessed for cardiac risk factors. The evaluation should reveal a history of hyperlipidemia, left ventricular (LV) hypertrophy, hypertension, or cigarette smoking or a family history of premature coronary artery disease (CAD). The presence of two or more risk factors increases the likelihood of acute MI.

Other associated symptoms are diaphoresis, exertional dyspnea, or dyspnea at rest. Presyncope or syncope, palpitations, generalized anxiety, and depression are other features indicative of poor cardiac function.

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Physical Examination

Cardiogenic shock is diagnosed after documentation of myocardial dysfunction and exclusion of alternative causes of hypotension, such as hypovolemia, hemorrhage, sepsis, pulmonary embolism, pericardial tamponade, aortic dissection, or preexisting valvular disease.

Shock is present if evidence of multisystem organ hypoperfusion in the presence of hypotension is detected upon physical examination (systolic blood pressure <90 mm Hg, cardiac index <2.2 L/min/m2, and  the presence of normal or elevated pulmonary capillary occlusion pressure [>15 mm Hg], or right ventricular [RV] end-diastolic pressure [RVEDP; >10 mm Hg]).

Characteristics of patients with cardiogenic shock include the following:

  • Patients in shock usually appear ashen or cyanotic and have cool skin and mottled extremities
  • Peripheral pulses are rapid and faint and may be irregular if arrhythmias are present
  • Jugular venous distention and crackles in the lungs are usually (but not always) present; peripheral edema also may be present.
  • Heart sounds are usually distant, and third and fourth heart sounds may be present
  • The pulse pressure may be low, and patients are usually tachycardic
  • Patients show signs of hypoperfusion, such as altered mental status and decreased urine output

A systolic murmur is generally heard in patients with acute mitral regurgitation or ventricular septal rupture. The associated parasternal thrill indicates the presence of a ventricular septal defect, whereas the murmur of mitral regurgitation may be limited to early systole. Approximately two thirds of patients will develop pulmonary congestion manifested as rales on pulmonary examination.

The systolic murmur, which becomes louder upon Valsalva and prompt standing, suggests hypertrophic obstructive cardiomyopathy (idiopathic hypertropic subaortic stenosis).

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