Chapter 11 Flashcards
Electrocardiography
tricuspid valve?
controls the blood flow from the right atrium to the right ventricle
mitral valve?
also called the “bicuspid valve”. controls the blood flow from the left atrium to the left ventricle through the valve
superior vena cava?
sends blood that is deoxygenated to the right atrium. The blood comes from the head, neck, chest, and upper extremities
aorta?
transports oxygenated blood to the body
systole?
occurs when the heart is contracting
diastole?
occurs when the heart is at rest, and the atria fills with blood
Purkinje Fibers?
transmits the impulse quickly and efficiently to the ventricular cardiac cells
polarized state?
before the impulse hits the cell, the cell is at resting potential. The inside of the cell is negatively charged
repolarized state?
after the impulse passes over the cell, the sodium and potassium ions move back to their original locations. This causes the cells charge to change back to a negative charge
PR segments?
it follows the P wave and appears as an isoelectric line. The electric impulse moves slowly through the AV node. The PR segment is the time between the end of atrial depolarization and the start of ventricular depolarization, when the atrial chambers finish contracting
J Point?
the point where the QRS complex ends and the ST segment begins
T wave?
follows the ST segment and appears as a smooth, rounded, asymmetric wave form. created from the electrical activity from ventricular activity
PR interval?
starts at the beginning of the P wave and ends at the start of the Q wave. It represents atrial depolarization
ventricular fibrillization?
(v-fib), occurs when the ventricle quiver uncontrollably. Essentially ineffective at pumping blood. The patient has no pulse and is unresponsive
AC interference?
alternating current interference. artifact or 60-cycle interference artifact, appears as a series of small spikes that create a thick looking tracing
Bundle of His?
located in the upper interventricular septum. when the impulse leaves the AV node, it moves to the bundle of his, also called the AV bundle
atrial depolarization interval?
the PR interval
ground electrode?
the right leg electrode is required for ECG tracing
precordial leads?
unipolar leads, each is a positive pole. They provide information on the horizontal plane of the heart. The six leads are labeled V1-V6
default gain of sensitivity?
100mm/mV
dextrocardia?
a condition in which the heart is located on the right side of the chest, and the apex is pointing towards the right. The electrodes must be placed on the right side of the chest using the same intercostal spacing, but the right and left limb wires are switched
interrupted baseline?
also called intermittent signal artifact. occurs when the tracing looks normal at the beginning but disappears or goes all over when the electrical connection is interrupted
somatic tremor?
also called muscle artifact. appears as jagged peaks with irregular heights and spacing
SA node?
“pacemaker of the heart”. located in the posterior superior wall of the right atrium. The cardiac cells in the SA node generate the impulse, and starts each heartbeat. The impulse moves quickly across the intermodal tracts