Unexpected cardiovascular collapse and death most often result from ventricular fibrillation in pts with atherosclerotic coronary artery disease or underlying structural heart conditions. The most common etiologies are listed in Table 11-1. Arrhythmic causes may be provoked by electrolyte disorders (especially hypokalemia), hypoxemia, acidosis, or massive sympathetic discharge, as may occur in CNS injury. Immediate institution of cardiopulmonary resuscitation (CPR) followed by advanced life support measures (see below) is mandatory. Without institution of CPR within 4–6 min, ventricular fibrillation or asystole is usually fatal.
Structural Associations and Causes |
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Functional Contributing Factors |
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Causes of Pulseless Electrical Activity Leading to Sudden Death |
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Basic life support (BLS) must commence immediately (Fig. 11-1):
Major steps in cardiopulmonary resuscitation. A. Begin cardiac compressions at 100−120 compressions/min. B. Confirm that victim has an open airway. C. Trained rescuers begin ventilation if advanced life support equipment is not available (pocket mask preferred if available). (Modified from J Henderson: Emergency Medical Guide, 4th ed. New York, McGraw-Hill, 1978.)
Management of cardiac arrest due to VF or VT. If metabolic acidosis persists after successful defibrillation and with adequate ventilation, also consider administration of 1 meq/kg NaHCO3. CPR, cardiopulmonary resuscitation; PCI, percutaneous coronary intervention; ROSC, return of spontaneous circulation; VF, ventricular fibrillation; VT, ventricular tachycardia. (Modified from HPIM-20, Figure 299-3A.)
Algorithms for bradyarrhythmia/asystole (left) or pulseless electrical activity (right) are dominated by cardiopulmonary resuscitation (CPR) and a search for reversible causes. MI, myocardial infarction. (From Albert CM, Stevenson WG: Cardiovascular collapse, cardiac arrest, and sudden cardiac death, in Jameson JL et al (eds). Harrison’s Principles of Internal Medicine, 20th ed. New York, NY: McGraw-Hill; 2018.)
If cardiac arrest resulted from ventricular fibrillation in initial hours of an acute MI, follow-up is standard post-MI care (Chap. 121: ST-Segment Elevation Myocardial Infarction). For other survivors of a ventricular fibrillation arrest, further assessment, including evaluation of coronary anatomy and left ventricular function is appropriate. In absence of a transient or reversible cause, placement of an implantable cardioverter defibrillator is usually indicated.
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