Cardiac Physiology Flashcards by Tiffany Ingle

Normal electrical activation

1 SA node

AV node
Bundle of His
Bundle branches (left and right)
Purkinje fibers

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Which is the fastest intrinsic rate

SA node

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Primary pacemaker

SA node

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What is the absolute refractory state

That period when a muscle cell is not excitable. From phase 1 until info phase 3.

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What is the relative refractory period

During phase 3 and the muscle cell contract is the stimulus is strong

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Electrocardiograph normal complex

P wave
P-R interval
QRS complex
T wave

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What does the P wave represent

Atrial systole

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What does P-R interval represent

From atrial to ventricular depolarization

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What does the QRS complex represent

Ventricular systole (depolarization)

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What does the T wave represent

Ventricular diastole (repolarization)

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What is the normal duration for the QRS complex

.10sec

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1 small box on the electrocardiograph is equal to

.04 seconds

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1 big box on the echocardiogram is equal to

.2 seconds

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5 big boxes on the electrocardiograph is equal to

1 second

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Normal values for R-R interval

Between 3 to 5 big boxes (60-100 beats per min)

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Normal values for QRS complex

Less than 3little boxes (less than .12 seconds)

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Normal values for PR interval

Less than 1 big box (less than .2 seconds )

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Frank starling law

Length tension relationship
-the more blood that enters the ventricle during diastole (preload) the greater the force of the contraction (systole) required to eject the blood. In other words, increased myocardial fiber length means increased tension

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Increased volume preload =

Increased contractility

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Increased myocardial fiber length =

Increased tension (river band theory)

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Acute AI is _________ because we shift up the starling curve.

Hypercontractile

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Chronic AI is ________ when we drop off the end

Failure

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Preload definition

Load (volume) exerted on the ventricle at end diastole

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Preload determines

Force of contraction

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The greater the load

The greater the force of contraction (frank starling law)

Increased preload is increased by

1. MR 2. TR 3. PI 4. AI 5. Ventricular and atrial septal defects 6. Fluid overload

Afterload definition

Resistance against which the ventricle must pump

Afterload determines

The tension the myocardium must generate

Echo finishings for preload

Dilation

Echo findings for afterload

Hypertrophy

After load is increased by?

Any state of pressure overload such as 1. Hypertension 2. Aortic stenosis 3. Pulmonic stenosis

LV function indicators

1. Stroke volume 2. Ejection fraction 3. Cardiac output

Stroke volume equation

SV= end diastolic volume (EDV) - end systolic volume (ESV)

Stroke volume varies with

End diastolic volume Heart rate Size

Ejection fraction

EF= stroke volume divided by end diastolic volume (100) | Normal is > 55%

Cardiac output definition

The volume of blood pumped from the LV each min

Cardiac output equation and norm

CO= stroke volume X heart rate | Normal is 4-6 L/min

``` Which study does not allow for the calculation of ejection fraction A) 2D echo B) cardiac angio C) chest x Ray D) cardiac nuclear study ```

Cheat x Ray

Bernoulli equation

4v squared

Aliasing

1. Occurs when the dipper shift excess the nyquist limit 2. Nyquist limit = half the PRf (pulse repetition frequency 3. A problem with higher velocities in pulsed Doppler (spectral and color flow) 4. Occurs sooner with higher frequency transducers

How do you eliminate aliasing on PW spectral Doppler

Switch to continuous wave Doppler

Doppler stroke volume

SV = VTI(FVI) times CSA

Doppler stroke volume | VTI

Is the velocity time integral as calculated by tracing the Doppler spectral display (sometimes called the flow velocity integral FVI) it represents how far the blood travels in centimeters with each ejection. Normally 12cm for the mitral and 20cm for aorta

Doppler stroke volume | CSA

Is the Ross sectional area calculated one of two ways 1. CSA (cm sq)= 3.14 times (D divided by 2) sq 2CSA (cm sq)= 0.785 tines Dsq D= the diameter of any office

Maneuvers altering cardiac physiology

1. Breathing2. Standing 3. Squatting 4. Hand grip 5. Valsalva 6. Sit ups 7. Amyl nitrite inhalation

Maneuvers altering cardiac physiology | - breathing

Inspiration: increases venous return | Expiration : decreases venous return

Maneuvers altering cardiac physiology | - standing

Decreases venous return and stroke volume

Maneuvers altering cardiac physiology | - squatting

Increased: venous return,SV,CO (Increases AR) (Decreases IHSS)

Maneuvers altering cardiac physiology | - handgrip

Increased: HR, CO , arterial pressure | Decreases: AS. Increased:MR

Maneuvers altering cardiac physiology | - valsalva

2 main phases-strain and release 1. During strain: decreases venous return,SV,CO (Most murmurs decreases during straining,IHSS increases) 2. During release: increases venous return, CO, BP

Maneuvers altering cardiac physiology | - sit ups

Increases HR,CO,and SV

Maneuvers altering cardiac physiology | - amyl nitrite inhalation

Vasodilator Decreases peripheral resistance Increases HR (Increases forward flow murmurs, decreases AR/MR)

Does venous return increase or decrease with inspiration

Increases

Inhalation of amyl nitrite causes

Decreases afterload

Mitral vavlve velocity during inspiration

Decreases

Between which heart sound will the murmur of aortic stenosis be heard?

S1-S2

know isovolumetric timing with ECG after R wave= After T wave=

after r wavw= isovolumic contraction | after T wave= isovolumic relaxation

on the wiggers diagram when is the mitral valve open

4-1

whats the duration of IVRT and IVCT

70msec

the duration of isovolumic relaxation time will increase with

bradycardia (slow heart rate)

during the cardiac cycle this event never happens

aortic valve is open and mv is open

correct order for cardiac cycle

1. mechanical diastole 2. electrical diastole 3. electrical systole 5. mechanical systole

normal arterial pressure is approx. _____. thus the aortic pressure lives ____

120/80 | lives high

normal left atrial pressure is approx. ____. thus the atrial pressure lives___

10mmHg | low

the left ventricular pressure bounces between ___ and ___.

aortic and atrial--> high and low

the valve that lies between the left ventricle and the aorta is the ____ it lives___

Aortic valve and it lives high

the valve that lives between the atrium and the left ventricle is the ___ and it lives____

MV lives low

when a normal valve is open, there is very little ____________ between the chambers on either side of the valve

pressure differences

when aortic valve is open , the LV and aortic pressures are?

nearly identical

when the mitral valve is open, the atrial and LV pressures are

nearly identical

Cardiac Physiology Flashcards

(70 cards)