B P7 C70 Cardiac Arrest and Sudden Cardiac Death Flashcards
SCD is natural death from cardiac causes heralded by abrupt loss of consciousness within _____ hour of the onset of an acute change in cardiovascular status.
1 hour
As such detailed information is often lacking, various definitions of SCD include up to a 24 hour period and death during sleep.
To satisfy clinical, scientific, legal, and social considerations, four temporal elements must be considered:
(1) Prodromes
(2) Onset
(3) Cardiac arrest
(4) Biologic death
The 1-hour definition primarily refers to the duration of the “_____,” which defines the interval between the onset of symptoms signaling the pathophysiologic disturbance leading to cardiac arrest and the onset of the cardiac arrest itself
Terminal event
_____, occurring weeks or months before an event, are generally predictors of an impending cardiac event, but not specific for SCA itself.
The same premonitory signs and symptoms may be more specific for imminent cardiac arrest when they begin abruptly.
Prodromes
Sudden onset of chest pain, dyspnea, or palpitations and other symptoms of arrhythmias often precede the onset of _____ and define the onset of the 1-hour terminal event period that brackets the cardiac arrest.
Cardiac arrest
The fourth element, _____, is an immediate consequence of cardiac arrest, unless there is a successful intervention, and usually occurs within minutes
Biologic death
Examples of substrate-based risk
Coronary heart disease
State of epicardial and intramyocardial vessels Myocardial infarction
Myopathy, infiltration, inflammation, valvulopathy Hypertrophy; myocardial fibrosis
Examples of expression-based risk
Left ventricular dysfunction and heart failure Metabolic abnormalities
Autonomic dysfunction
Examples of mechanism-based risk
VF/pulseless VT
PEA
Asystole
Three factors are of primary importance for identification of populations at risk and consideration of strategies for prevention of SCD:
(1) the Absolute numbers and event rates (incidence) among population subgroups
(2) the Clinical subgroups in which SCDs occur
(3) Competing risks
(4) the time dependence of risk
Genetic Contributors to Risk for Sudden Cardiac Death
Genetically Based Primary Arrhythmia Disorders
Congenital long-QT syndrome, short-QT syndrome Brugada syndrome
Catecholaminergic polymorphic VT/VF
J wave syndromes
Nonsyndromic VT/VF
Genetic Contributors to Risk for Sudden Cardiac Death
Inherited Structural Disorders with Risk for Arrhythmic SCD
Hypertrophic cardiomyopathy
Right ventricular dysplasia/cardiomyopathy
Genetic Contributors to Risk for Sudden Cardiac Death
Genetic Predisposition to Induced Arrhythmias and SCD
Drug-induced “acquired” long-QT syndrome (drugs, electrolytes)
Electrolyte and metabolic arrhythmogenic effects
Genetic Contributors to Risk for Sudden Cardiac Death
Genetic Modulation of Complex Acquired Diseases
Coronary artery disease, acute coronary syndromes Congestive heart failure, dilated cardiomyopathies