Harrison's Pulmonary and Critical Care Medicine, by Joseph Loscalzo

Author:Joseph Loscalzo
Language: eng
Format: epub
Publisher: McGraw-Hill Education
Published: 2013-09-22T04:00:00+00:00

TABLE 31–1

DISTINCTION BETWEEN CARDIOVASCULAR COLLAPSE, CARDIAC ARREST, AND DEATH

CLINICAL DEFINITION OF FORMS OF CARDIOVASCULAR COLLAPSE

Cardiovascular collapse is a general term connoting loss of sufficient cerebral blood flow to maintain consciousness due to acute dysfunction of the heart and/or peripheral vasculature. It may be caused by vasodepressor syncope (vasovagal syncope, postural hypotension with syncope, neurocardiogenic syncope, a transient severe bradycardia, or cardiac arrest. The latter is distinguished from the transient forms of cardiovascular collapse in that it usually requires an intervention to restore spontaneous blood flow. In contrast, vasodepressor syncope and other primary bradyarrhythmic syncopal events are transient and non-life-threatening, with spontaneous return of consciousness.

The most common electrical mechanism for cardiac arrest is ventricular fibrillation (VF), which is responsible for 50–80% of cardiac arrests. Severe persistent bradyarrhythmias, asystole, and pulseless electrical activity (PEA: organized electrical activity, unusually slow, without mechanical response, formerly called electromechanical dissociation [EMD]) cause another 20–30%. Pulseless sustained ventricular tachycardia (a rapid arrhythmia distinct from PEA) is a less common mechanism. Acute low cardiac output states, having a precipitous onset, also may present clinically as a cardiac arrest. These hemodynamic causes include massive acute pulmonary emboli, internal blood loss from a ruptured aortic aneurysm, intense anaphylaxis, and cardiac rupture with tamponade after myocardial infarction (MI). Sudden deaths due to these causes are not included in the SCD category.

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