A 63-year-old woman fell while crossing the street after her Thursday afternoon bridge game. Attempts at resuscitation for cardiac arrest by the emergency medical service (EMS) team were unsuccessful. The woman had previously been diagnosed as having aortic stenosis and left ventricular hypertrophy. In addition to these factors, which of the following predisposes to sudden cardiac death?

Sudden cardiac death is defined as an unexpected death occurring within 1 hour after the beginning of symptoms in a patient who was previously hemodynamically stable. In asymptomatic patients presenting initially with cardiac disease, 20% will die within the first hour of symptoms. Electrolyte imbalance, hypoxia, and conduction system defect are additional factors that increase the risk of sudden death syndrome. Split first heart sound accentuated on inspiration occurs in normal individuals. In CHF, the CVP changes more than 1 cm when pressure is applied below the right costal margin to the liver (hepatojugular reflex) for a 30-second period.New York Classification of Functional changes in Heart DiseaseClassLimitation of Physical ActivityINoneIISlightIIIMarkedIVComplete (even at rest)