OVERVIEW AND DEFINITIONS
Cardiovascular collapse is severe hypotension from acute dysfunction of the heart or peripheral vasculature causing hypotension with resulting cerebral hypoperfusion and loss of consciousness that can be the result of a cardiac arrhythmia, severe myocardial or valvular dysfunction, loss of vascular tone, and/or acute disruption of venous return (see Table 299-1). When an effective circulation is restored spontaneously, patients present with syncope (see Chap. 18). If spontaneous resolution does not occur, then cardiac arrest occurs, ultimately resulting in death if resuscitation attempts are unsuccessful or not initiated. Underlying etiologies for cardiovascular collapse include benign conditions such as vasovagal syncope, but also life-threatening conditions, including: ventricular tachyarrhythmias, severe bradycardia, severely depressed myocardial contractility, as with massive acute myocardial infarction (MI) or pulmonary embolus, and other catastrophic events interfering with cardiac function such as myocardial rupture with cardiac tamponade or papillary muscle rupture with torrential mitral regurgitation.
++ Table Graphic Jump Location Table 299-1Distinction between Cardiovascular Collapse, Cardiac Arrest, and Death ||Download (.pdf) Table 299-1 Distinction between Cardiovascular Collapse, Cardiac Arrest, and Death
|Term ||Definition ||Qualifiers ||Mechanisms |
|Cardiovascular collapse ||Sudden loss of effective circulation due to cardiac and/or peripheral vascular factors that may reverse spontaneously (e.g., neurocardiogenic syncope, vasovagal syncope) or require interventions (e.g., cardiac arrest). ||Broad term that includes cardiac arrest and transient events that characteristically revert spontaneously presenting as syncope. ||Same as “Cardiac Arrest,” plus vasodepressor syncope or other causes of transient loss of blood flow. |
|Cardiac arrest ||Abrupt cessation of cardiac function resulting in loss of effective circulation which may be reversible by prompt emergency medical intervention, but will lead to death in its absence. ||Rare spontaneous reversions; likelihood of successful intervention relates to mechanism of arrest, clinical setting, availability of emergency medical services, and prompt return of circulation. ||Ventricular fibrillation, ventricular tachycardia, asystole, bradycardia, pulseless electrical activity, noncardiac mechanical factors (e.g., pulmonary embolism). |
|Sudden cardiac death ||Sudden unexpected death attributed to cardiac arrest, which if witnessed occurs within one hour of symptom onset. ||In unwitnessed cases, the definition is often expanded to include unexpected deaths where the subject was documented to be well within the preceding 24 h. ||Same as Cardiac Arrest. |
Sudden cardiac arrest (SCA) refers to an abrupt loss of cardiac function resulting in complete cardiovascular collapse due either to an acute life-threatening cardiac arrhythmia or abrupt loss of myocardial pump function that requires emergency medical intervention for restoration of effective circulation. Most SCAs occur outside the hospital, and fewer than 10% of these victims survive to be discharged from the hospital despite undergoing attempted resuscitation by emergency medical services (EMS). For those that die prior to hospital admission, a cardiovascular cause for ...