common disorders ch 15 Flashcards
myocardial ischemia
partial obstruction of blood flow in the coronary arteries, condition of reduced blood flow to the myocardium
ischemia causes hypoxia
reduced oxygen supply
angina pectoris
strangled chest, severe pain that usually accompanies myocardial ischemia
silent myocardial ischemia
ischemic episodes with no forewarning of an impending heart attack
myocardial infarction
complete obstruction to blood flow in a coronary artery…heart attack
congenital defect
defect that exists at birth (and usually before)
patent ductus arteriosus (PDA)
the ductus arteriosus between the aorta and pulmonary trunk, which normally closes shortly after birth remains open
atrial septal defect (ASD)
incomplete closure of the interatrial septum
ventricular septal defect (VSD)
incomplete closure of the interventricular septum
valvular stenosis
narrowing of one of the valves associated with blood flow through the heart
tetralogy of fallot
4 defects: interventricular septal defect, an aorta that emerges from both ventricles instead of from the left ventricle only, narrowed pulmonary semilunar valve, enlarged right ventricle
arrhythmias
dysrhythmia
abnormal rhythm as a result of a defect in the conduction system of the heart
supraventricular tachycardia- arrhythmia
rapid but regular heart rate (160-200 beats per minute) that originates in the atria…minutes to many hours
heart block- arrhythmia
arrhythmia that occurs when the electrical pathways between the atria and ventricles are blocked, slowing the transmission of nerve impulses
- atrioventricular block is most common
atrial premature contraction (APC)
heartbeat that occurs earlier than expected and briefly interrupts the normal heart rhythm
atrial flutter
rapid, regular atrial contractions (240-360 beats per min) accompanied by an atrioventricular block so nerve impulses from SA node are not conducted to AV node
atrial fibrillation (AF)
contraction of atrial fibers are not in unison
atria 300-600bpm
ventricles 160bpm
ventricular premature contraction
wave of depolarization spreads outward from the ectopic focus, ventricular premature contraction (beat)
ventricular tachycardia
originates in the ventricles, characterized by 4 or more ventricular premature contractions
dangerous
low bp and heart failure
ventricular fibrillation
deadly arrhythmia, in which contractions of the ventricular fibers are completely asynchronous so that the ventricles quiver rather than contract
unconsciousness in seconds, if untreated seizures and irreversible brain damage after 5 min
treatment for vfib
CPR and defibrillation
defibrillation
cardioversion
strong, brief electrical current is passed through the heart and can often stop the ventricular fibrillation
-electrical shock is delivered by defibrillator
