Cardiology I Flashcards
What occurs during ventricular systole?
Contraction of the ventricles which sends blood to the body and lungs.
What controls the opening and closing of the heart valves?
Chamber pressure.
What occurs during ventricular diastole?
Relaxation of the ventricles which allows them to refill
What are the two left coronary arteries?
Anterior descending and circumflex arteries
What part of the heart does the circumflex artery supply?
It supplies the left and around the back of the heart
What is the right coronary artery?
Posterior interventricular artery
What vein does the heart empty into (coronary)?
The great coronary vein.
The vein that filters the heart is called the _____ and it empties into the _______.
Great coronary vein; right atrium.
What is the blood flow through the heart?
Vena cava Right atrium Tricuspid valve Right ventricle Pulmonary valve Pulmonary artery Lungs Pulmonary vein Left atrium Bicuspid valve Left ventricle Aortic valve Aorta Body.
______ is the contraction of the ventricles.
Systole
______ is the period in which the ventricles fill with blood from the atria.
Diastole
What is the time of one contraction & one relaxation?
Cardiac cycle
What is the length of one cardiac cycle?
Approx. 0.8 seconds
What is the length of systole?
Approx. 0.2 seconds
What is the length of diastole?
Approx. 0.52 seconds
_____ is the measurement of the amounts of blood pumped out the ventricles.
Ejection fraction
Ejection fraction is the measurement of the amounts of what?
Blood pumped out the ventricles.
What is the normal value of ejection fraction?
55-70%
What part of the cardiac cycle lasts approximately 0.2 seconds?
Systole.
What part of the cardiac cycle lasts for approximately 0.52 seconds
Diastole
What lasts approximately 0.8 seconds?
One cardiac cycle
______ is the amount of blood pumped out of ventricles in a single beat.
Stroke volume.
___ is the pressure in the ventricles at the end of diastole.
Preload
What is preload?
The amount of pressure at the end of diastole.
Preload is directly affected by the volume of blood that what?
Returns to the right atrium
_____ is the resistance against which the heart must pump against.
Afterload
Afterload is what?
The resistance against which the heart must pump against.
What law deals with the stretching of the myocardia?
Sterling’s Law
What does Sterling’s law state?
The myocardium can be stretched and will return to its normal state, but if overworked (stretched too far) it will lose its ability to return to its normal state.
What is peripheral vascular resistance?
How much pressure is in the arterioles that the heart must pump against.
______ is the amount of pressure in the arterioles that the heart must pump against.
Peripheral vascular resistance
Peripheral vascular resistance is determined by what?
Vasoconstriction and vasodilation
What is the correlation between the heart rate and the amount of CO2?
⬆️ HR, ⬇️ CO2
What is the formula for blood pressure?
Blood pressure = CARDIAC OUTPUT x PERIPHERAL VASCULAR RESISTANCE
_____ is the flight or fight response whereas ____ is the rest and digest response
Sympathetic — fight or flight
Parasympathetic — rest and digest
Sympathetic and parasympathetic nervous responses are a part of what,
Autonomic
The receptors in the sympathetic nervous system are ___ and ___.
Alpha and beta
What chemical neurotransmitters are in the sympathetic nervous system?
Norepinephrine
What nerve endings are in the sympathetic nervous system?
Adrenergic
Alpha one receptors do what?
vasoconstriction which raises blood pressure
Alpha two receptors do what?
Stop vasoconstriction.
Beta one receptors are located where?
In the heart
Beta two receptors are located where?
In the lungs.
Beta two receptors cause what?
Bronchodilation and Vasodilation
What are the neurotransmitters for the parasympathetic nervous system?
Acetylcholine
Acetylcholine nerve endings are called what?
Cholinergic.
Cholinergic nerve endings are what?
Parasympathetic nerve fibers that use acetylcholine as neurotransmitters.
Adrenergic nerve endings are what?
Sympathetic nerve fibers that use epinephrine as neurotransmitters.
Myocardial working cells do what?
Generate the PHYSICAL contraction of heart cells.
What generates blood flow?
Physical contractions of myocardial working cells
What do pacemaker cells control?
Rate and rhythm by coordinating regular depolarization
Depolarization is…
Contractions of the heart.
What is the primers function of pacemaker cells?
To generate and conduct electrical impulses
A ____ is the point at which a stimulus will produce a cell response.
Threshold
What are the four cardiac cell characteristics?
Contractibility (mechanical)
Automaticity (electrical)
Excitability (electrical)
Conductivity (electrical)
_____ is the ability of the cardiac cells to shorten and cause muscle contraction.
Contractility
____ is the ability of the cardiac pacemaker cells to spontaneously generate electrical impulses w/o external stimulation.
Automaticity
____ is the ability of cardiac cells to respond to an electrical stimulus.
Excitability
_____ is the ability of cardiac cells to receive/transmit stimulus to other cardiac cells.
Conductivity
Where is the location of automaticity?
SA NODE, AV JUNCTION, PURKINJE FIBERS
_____ is a substance or compound whose molecules dissociate into charged components (ions)
Electrolytes.
_____ performs a vital part in depolarization of myocardium
Sodium
What occurs during cardiac depolarization?
Sodium ions rush into cell changing interio charge to positive after cell is stimulated.
What happens during cardiac repolarization?
Sodium ions returns to outside of the cell and potassium ions return to inside.
What is the charge of the inside and outside of the cell during resting membrane potential?
Negative inside
Positive outside
What occurs during action potential?
Changes in polarity produces change in cells.
____ are attempts to ensure muscle is totally relaxed before another depolarization can be initiated.
Refractory period
What is the refractory period for the atrial muscle?
0.15 seconds
What is the refractory period for the ventricular muscle?
0.25-0.3 seconds
Period of rest is called ____.
Cardiac repolarization
The ____ is the primary pacemaker of the heart.
SA node
What cardiac wave is caused by the SA node?
The P-Wave
What is the firing rate of the SA node?
60-100 BPM
What receives the impulse as it exits the SA node?
The internodal pathways
The internodal pathways deliver the impulse where?
From the SA node, throughout the atria, and to the AV node
What delivers the impulse from the left atrium to the right atrium?
Bachmann’s bundle (wenckebach’s bundle)
At the AV node electrical activity delays _____
0.05 seconds
Why does the impulse delay at the AV node?
To allow for complete filling of the ventricles
What is the firing rate of the AV node?
40-60 BPM
What is the secondary pacemaker?
AV node
Where is the bundle of his located?
The top of the interventricular septum
What is the firing rate of the bundle of his?
20-40 BPM
What is the firing rate of the purkinje network?
20-40 BPM
Where does the impulse go from the purkinje network?
To the ventricular muscle cells.
What is the pathway of electrical conduction in the heart?
SA node Interventricular pathways bachmann's bundle AV node Bundle of his Left and right branches Purkinje fibers Ventricular muscle cells
EKG is the graphing of what activity in the heart?
Electricak
What is placed on the skin to sense electrical activity?
Electrodes
How is EKG recorded?
Electrocardiogram
The ____ are the pads that go on the patients skin whereas the ____ connect to the cardiac monitor.
Electrodes - skin
Leads - machine
Three leads are named because they must have what?
A positive, a negative and a ground
What is einthoven’s triangle?
And imaginary inverted triangle formed around heart by proper positioning oft the bipolar leads.
Lead one goes where?
Left & right arm
Lead two goes where?
Left leg and right arm
Lead 3 goes where?
Left leg and arm
Time is measured on the ____ line of the ekg graph.
Horizontal.
Voltage is measured on the ___ line of the ekg paper
Vertical
One small box meaures ___ seconds
0.04 seconds.
PRI is how long ?
0.12-0.20 seconds
One large box is equal to how long?
0.20 seconds
QRS is how long?
Less than 0.12 seconds
The ____ is the beginning and ending of all waves
Isoelectric line
A _____ is above the isoelectric line.
Positive deflection
A ____ is below the isoelectric line.
Negative deflection.
The P wave is how long
10 seconds
What is the P wave
depolarization of the left and right atria
What is the PR interval
Start of the P wave to the start of the QRS complex
How long is the PRI?
0.12-0.20 seconds
The QRS complex represents what?
Ventricular depolarization
The S wave is how long?
Less than 0.12 seconds
The ST segment is what?
Ventricles are depolarizes and repolarization begins
Elevation and/or depression of the ST segment is indicative of what?
An acute myocardial infarction
STEMI is what?
An elevated ST segment
Angina is what?
A depressed ST segment
The T wave represents what?
Ventricular repolarization
The T wave is what phase of the cardiac cycle?
Resting phase
The P wave is what?
Atrial depolarization
The QRS complex is what?
Atrial repolarization/ventricular depolarization
The T wave is what?
Ventricular repolarization
What are causes of sinus arrhythmia?
MI
Sick Sinus Syndrome
Medications
What are causes of sinister arrest?
Hypoxia Ischemia Damage to SA node Acute MI digitalis & salicylates
What are causes of atrial dysrrhythmia?
COPD
Digitontoxitity
Electrolyte imbalances
What are the 5 steps to interpret EKGs?
HR Heart Rhythm P wave PRI QRS Complex
What are causes of PACs?
Increased sympathetic tone Digitalis toxicity Hypoxia Stimulants Caffeine
How many PACs must happen for they to be called frequent?
More than 6
Two sequential PACs is called a…
Couplet
When every other beat is a PAC that is called…
Atrial bigemity
Every third beat being a PAC is called what?
Atrial trigemity
What is the reactivation of myocardial tissue for a second or subsequent time by the same impulse?
ReEntry dysrrhythmia
What causes the short circuit of electrical conduction?
A delay or block
What are causes of reentry dysrhythmias?
Hyperkalemia
Myocardial ischemia
Certain antidysrhythmia meds
What type of rhythms are reentry dysrhythmias?
A-flutter A-fibrillation PAC PSVT SVT
What are 3 characteristics of A-Fibrillation
There are no p waves
F waves replace p waves
Ventricle response is irregularly irregular
What are causes of Atrial fibrillation?
Heart disease CHF Rheumatic heart disease Hypoxia Digitalis toxicity Electrolyte imbalance
When your patient is in A-fibrillation and their heart rate is greater than 100 they are considered ______ if their heart rate is less than 100 they are considered _______.
Unstable; stable
When you cardiovert a patient you use how many J?
50
