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KEY FEATURES

ESSENTIALS OF DIAGNOSIS

  • Unexpected death within 1 hour of onset of symptoms; if a patient is successfully resuscitated, it is called a sudden death episode

  • Primary electrical mechanisms include:

    • – Ventricular fibrillation (VF)

    • – Ventricular tachycardia (VT)

    • – Asystole

    • – Pulseless electrical activity

  • May also be due to massive pulmonary embolism, rupture of an aortic aneurysm, or massive stroke

GENERAL CONSIDERATIONS

  • Each year, 300,000 individuals in the United States die suddenly from cardiovascular disease

  • Associated diseases include:

    • – Coronary artery disease

    • – Dilated cardiomyopathy

    • – Hypertrophic cardiomyopathy

    • – Arrhythmogenic right ventricular dysplasia

    • – Primary electrophysiologic disorders such as long QT syndrome, Brugada’s syndrome, and idiopathic ventricular arrhythmia

  • Patients with ischemic heart disease are the largest single group at risk for sudden death

  • Myocardial infarction (MI)–related scar is the substrate, and the triggering event may be ischemia, electrolyte imbalance, autonomic dysfunction, or drug toxicity

  • Ejection fraction (EF) is an important predictor of survival in those who survive an episode of sudden death

    • – EF is also an important tool in assessing the risk for sudden death

    • – The lower the EF (< 0.35), the higher the risk and maximal benefit from primary prevention therapy (implantable cardioverter-defibrillator [ICD])

  • Sudden cardiac death is rare among patients with structurally normal hearts

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

  • Cardiac arrest

  • Patients may arrive at the hospital after successful resuscitation

PHYSICAL EXAM FINDINGS

  • Assess hemodynamic stability

  • Many patients are on ventilatory support

  • Shock, cold clammy extremities, and pulmonary edema are not uncommon

  • Features of neurologic insult may be primary or secondary to prolonged resuscitation and anoxic encephalopathy

  • Aortic regurgitation murmur secondary to dissection of the aorta

  • Gray Turner’s or Cullen’s sign secondary to intraperitoneal hemorrhage secondary to rupture of aortic aneurysm

DIFFERENTIAL DIAGNOSIS

  • Syncope

  • In young patients, consider coronary artery anomalies, with intermittent ischemia giving rise to ventricular arrhythmia

  • Drug-induced torsades de pointes

DIAGNOSTIC EVALUATION

LABORATORY TESTS

  • CBC, comprehensive metabolic panel including thyroid-stimulating hormone

  • Cardiac biomarkers

  • Arterial blood gas analysis

ELECTROCARDIOGRAPHY

  • ECG to evaluate for acute MI, ischemia or arrhythmia such as VT, evidence of preexcitation, long QT syndrome, or Brugada pattern ECG

IMAGING STUDIES

  • Both transthoracic and transesophageal echocardiogram:

    • – To evaluate left ventricular function

    • – To assess the aorta for dissection, valvular function, right ventricular dilatation (suggests pulmonary embolism), and hemodynamic status

  • Spiral CT of the chest

  • CT of the head

DIAGNOSTIC PROCEDURES

  • Depends on the suspected cause, but electrophysiology study may be indicated

  • Coronary angiography to assess for coronary artery disease and acute MI if the clinical situation permits

TREATMENT

CARDIOLOGY REFERRAL

  • All patients should be seen by a cardiologist

  • Cardiologist ...

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