ECGs made easy

which term refers to the basic protein units responsible for contraction of the cardiac muscle?

sarcomeres

whic of the following determines coronary artery dominance?

artery giving rise to posterior descending artery

which of the following is the origin of the first heart sound (“lubb”)?

ventricular contraction when AV valves are closing

T or F: the right heart functions as the systemic pump and under high pressures

false

which two coronary arteries are the first to branch off of the aorta?

right and left coronary arteries

the term for the junction that connects cardiac muscle fibers is:

intercalated disks

T or F: the heart receives oxygenated blood during systole

false

T or F: cardiac tamponade is considered a life-threatening condition

true

the layers of the heart from inner to outer are:

endocardium, myocardium, epicardium, pericardium

the atrioventricular valves differ from the semilunar valves in all but the following?

keep blood flowing forward

which of the following is referred to as chronotropy?

change in heart rate

Alpha1 & 2, Beta 1&2, dopamine receptor sites are receptors in which autonomic nervous system?

sympathetic nervous system

which of these is the largest vein that drains the heart muscles?

coronary sinus

muscarinic receptors in cardiac muscle act in which manner?

slows the natural pacing rate of the heart

which of the following is a possible cause of inadequate oxygen supply to the myocardium?

anemia

another name given to the sympathetic response is:

autonomic response

given a situation in which a patient has been determined to have suffered a temporary or permanent blockage of a coronary artery, the diagnosis could include which of these terms?

acute coronary syndome

the parasympathetic nervous system controls

rest and digest response

T or F: myocardial ischemia, if not reversed, can lead to myocardial infarction, which is death of the myocardial tissue affected by ischemia

true

what is the definition of angina pectoris?

symptoms such as chest discomfort of sudden onset

specialized nerve tissue that detect changes in blood pressure are known as

baroreceptors

the sympathetic nervous system controls

fight and flight response

what two factors determine cardiac output?

stroke volume, heart rate

epinephrine and norepinephrine are two hormones that are secreted by the adrenal medulla and may cause what to happen?

increase the force of the heart’s contraction

T or F: the cardiac output of the right ventricle is normally equal to that of the left ventricle on a minute-to-minute basis

true

what term refers to the force exerted on the walls of the ventricles at the end of diastole?

preload

what term refers to the pressure or resistance against which the ventricles must pump to eject blood?

afterload

what is the “atrial kick”?

contraction of atria from SA node impulse

what is the normal range of right atrial pressure?

2-6 mmHg

during which part of the cardiac cycle does blood return to the heart?

atrial diastole

T or F: the stroke volume and ejection fraction are expressed the same way and mean the same thing

false

blood pressure is defined as:

force exerted by circulating blood on walls of arteries

if a patient’s stroke volume decreases, what must occur with the heart rate to maintain a constant cardiac output?

increase

what do electrical charges of opposite polarity posses when they are separated?

potential energy

T or F: depolarization is the same thing as contraction

false

where does the 5 phases of the “fast response action potential” occur?

atrial & ventricular myocardial cells, purkinje fibers

what makes pacemaker cells unique compared to other cells?

capable of generating an electrical impulse without nerve stimulation

the difference in electrical charges across cell membrane is expressed as:

membrane potential

what occurs in cells during depolarization

inside of cell becomes positive

what alternate name do myocardial cells have?

mechanical cells

what are electrolytes, such as sodium, potassium, and calcium which carry a positive charge known as?

ions

what state of a cell exists when at rest and the inside of the cell is more negative than the outside?

polarized

what term is defined as the ability of cardiac muscle to respond to external stimulus?

excitability

any beat that originates from a source other than the SA node is called a(n) ___ beat.

ectopic

what period of the cardiac cycle can elicit no response to further stimulation?

absolute refractory period

T or F: the electrical conduction across the AV node is transmitted rapidly to the ventricles

false

what is the term which applies to the spread of an impulse already stimulated by that same impulse?

reentry

two nodes are located in the heart; they are correct as listed below:

AV node-floor right atrium, SA node-upper right atrium

the left bundle branch divides into three division known as:

fasciles

cardiac cells that do not normally function as pacemaker cells which begin to spontaneously depolarize and pacemaker sites other than the SA node suddenly increasing the normal firing rate is called

enhanced automaticity

the _______ has a firing rate of 20-40 BPM

purkinje fibers

where, in the heart’s conduction system, is the speed of impulse conduction the fastest?

His-purkinje system

an accessory pathway is:

an abnormal pathway bypassing the AV node

the difference in placement of non-standard chest leads V7-V9 as opposed to V1-V6 is:

placed further left and towards the back

T or F: each electrode placed in a “V” position is a positive electrode

true

Leads I, II, and III axes form what with the heart at the center? be specific and spell correctly!

Einthoven’s triangle

what non-standard leads can be utilized to visualize infarction of the right ventricle?

V1R-V6R

a reference point that is the average of the limb lead electrical potentials is known as

central terminal

which leads view the heart in the frontal plane?

standard limb leads, augmented limb leads

T or F: horizontal plane leads view the front of the body as though it were flat

false

how many “large” boxes on ECG tracing paper composes the time frame of 1 second?

5

T or F": all three waves must be present for a QRS complex to be considered normal

false

T or F: waveforms are always positive in direction

false

in what manner is the width of the QRS complex most accurately determined?

viewed and measured in more than one lead

in a patient that has a condition such as heart failure or COPD the “P” wave may appear as:

tall and pointed

which explanation describes the QRS complex?

represents ventricular depolarization primarily of left ventricle

what time frame is represented by each “large” box on ECG tracing paper?

.20 seconds

which wave when pronounced in its amplitude and width, can be the marker for myocardial infarction?

Q wave

the vertical axis of ECG graph paper represents

voltage and amplitude

in regards to how each lead “views” the heart two factors determine what each lead sees; one of these factors is the dominance of the left ventricle on the ECG and the second is:

position of the positive electrode on the body

U waves are thought to represent

repolarization of purkinje fibers

T or F: any deviation of the ST segment from the isoelectric line is considered abnormal

false

a peaked T wave could be caused by:

hyperkalemia

R-R measurement determines regularity of ________ and P-P measurements determines regularity of _________.

ventricles, atria

the place on the ECG tracing where the relative refractory period can have greatest impact is

T wave

“Smiley face” and “frowny face” are used in reference to

ST segment

in the large box method of rate determination, the number of large boxes between two consecutive R waves is divided into

300

a cause of an artifact on an ECG tracing could be

all of the above

an abnormal QRS wave is longer than

.11 sec

the fastest way and the method most used to determine ventricular rate is called

six second method

a rapid way to measure QT intervals’ normalcy is to

measure R-R and divide by 2

which of the following is not included when interpreting a rhythm

respiratory rate

the appearance of a variation of less than 0.04 second between the shortest and longest R-R intervals is said to be

essentially regular

the normal length of the PR interval should be between _____ for adults

.12-.20 sec

torsades de pointes is a life-threatening condition that can be caused by

prolonged QT interval, prolonged relative refractory period

PR segments on ECG tracings are usually

horizontal