Exercise Testing Prescription Exam 2

Polarized

Separation of charge across a plasma membrane

• net negative internal electrical charge

• net positive external electrical charge

Depolarization

Internal charge shifts to a less negative value due to influx of positive ions

Repolarization

Polarized voltage is restored inside the cell due to efflux of positive ions

Systole

Diastole

End diastolic volume

End systolic volume

Stroke volume

What are the 2 types of cells that make up cardiac tissue

Myocardium Contractile Cells

Myocardium Conductive Cells

Myocardium CONTRACTILE Cells Properties

90 - 95% hearts mass

Contractile - generate force

Excitable - respond to electrical stimulus

Conductive - move electric charge from one cell to another

Myocardium CONTRACTILE Cells Features

Striated

Multiple Large Mitochondria

Lots of myoglobin

Intercalated discs

Heart only uses _____ metabolism

aerobic

Myocardium CONDUCTIVE Cells Properties

5 - 10% heart mass

Automaticity

Excitable

Conductive

Myocardium CONDUCTIVE Cells Features

Unique ion cells

Intercalated discs

Regulated by the autonomic nervous system

Prepotential (PP) what ion? What direction does it move?

Na+ move INTO the cell

Depolarization what ion? What direction does it move?

Ca2+ moves INTO the cell

Repolarization what ion? What direction does it move?

K + moves OUT of the cell

What is the charge for resting membrane potential threshold

-40 mV

Names and parts of the cardiac intrinsic conduction system

Pacemaker (SA NODE) - Top of RA

AV node - Bottom of RA

Bachmans bundle - Top of LA (interatrial pathway)

AV bundle - under AV node

Right BB - in septum

Left BB - atrioventricular septum

Purkinje fibers - tiny in outer wall of the ventricles

What is the normal order of depolarization (sequence of firing)

SA node (60-100)

AV node/Bachmans Bundle

AV bundle

RBB and LBB

Purkinje Fibers

2 basic types of muscle fiber arrangement

Circular fibers (squeeze)

Longitudinal fibers (twist)

How does the muscle fiber arrangement boost blood ejection?

They squeeze and twist like a washrag

Wave

a deflection either positive or negative away from isoelectric line

Segment

a line between waves or complex

Interval

a wave + a segment together

Complex

several waves together

Isoelectric

flat line/baseline tissue in resting polarized state

Lead

viewpoint you use to evaluate cardiac electric current

Electrode

Placed on the skin to make leads

When we see an isoelectric line what do we know

No activity heart is at rest

What does duration on a tracing tell us

milliseconds

What does amplitude on a tracing tell us

millivolts

Einthovens Triangle

RA LA LL

Lead 1

RA - LA +

Lead 2

RA - LL +

Lead 3

LA - LL+

What axis measures time? What is the unit of measurement?

Horizontal, milliSeconds

What axis measures charge? What is the unit of measurement?

Vertical, millivolts

What are the dimensions of small boxes? What are the time and charge equivalencies?

40msec by 0.1mV

What are the dimensions of large boxes? What are the time and charge equivalencies?

200msec by 0.5 mV

Label ECG complex

P QRS T U

What part is associated with SA node and atrial depolarization?

P wave or PR interval

What part is associated with ventricular depolarization?

QRS complex

What part is associated with ventricular repolarization?

T wave

How is depolarization and repolarization linked to systole and diastole?

Depolarization —> Systole

Repolarization —> Diastole

Identify the normal morphology, deflection direction, and duration* for P wave

round symmetrical

positive

<120 msec

Use 1500 method

1500/ average of 3 nonconsecutive R-R intervals

Normal changes during exercise test on ECG

DEC DUR (FASTER HR)

INC AMP

R WAVE AMP INC

T WAVE PEAK AMP

MERGING PT WAVE WITH HR > 150 HR

Signify poor perfusion, sequence they occur and is a pathological Q wave?

Baseline

Hyperacute T Wave

ST elevation

Evolve ST

Q wave

T wave inversion

Baseline w/ Q wave

Identify the normal morphology, deflection direction, and duration* for PR interval

120 - 200 msec

Identify the normal morphology, deflection direction, and duration* for QRS complex

negative positive negative

120 msec or less

Identify the normal morphology, deflection direction, and duration* for ST segment

flat isoelectric

Identify the normal morphology, deflection direction, and amplitude* for T wave

asymmetric with peak to right

positive

< 0.5 mV

Pathological Q wave MEET BOTH CRITERIA

Duration - above or equal to 40mSec

Amp - above or equal to 0.2mV or more than 25% R wave

Deeper the Q wave the more _______ damage

ischemic

Common Dysrhythmias

Normal Sinus

Sinus bradycardia

Sinus tachycardia

Sinus arrhythmia (>3 small box variable)

Dysrhytmias SVT pacemaker, sign/symptom, clinical significance, benefits of exercise, impact on aerobic exercise prescription

T and P TOGETHER

HR REGULAR BUT HIGH (150 - 220 bpm)

In atria but NOT SA NODE

What do we want to see for heart to fix itself?

isoelectric line, reset

Atrial Arrythmias

MULTIPLE LOW AMPLITUDE P WAVES

multiple sites in atria

IRREGULAR HR

Atrial flutter

in atria 3-4

SAW TOOTHED

3:1 or 4:1

Is it safe for people with atrial arrhytmias to exercise?

YES IF CLEARED BY PREPARTICIPATION SCREENING

Beenfits of exercising for the dysrhymia people

10-15% improvement in ADLs

Decrease submax HR

reduced dyspnea, fatigue, and palpitations

shortened daily dysrhythmias

Which response to prescribe can we absolutley not use for dysrhytmias ppl?

HR RESPONSE TO VARIABLE

Validity

Degree which test measures what is is intended to measure

Reliability

Consistency or repeatability

Test mode

exercise modality used/ equipment

Test protocol

procedure to do test

Field test

Outside lab with minimal equipment

Lab test

In controlled lab using equipment

Indication

USE THE PROGRAM

Contraindication

DONT USE THE PROGRAM

The types of testing modalities, suited for? limitations?

Types of protocols, suited for? limitations?

Pretest instructions for CRF

No food, caffeine, nicotine at least 3 hours before testing

No exercise 24 hours prior

Driver afterwards

Normal medicine routine

Bring list of current medication and last dose

When is CRF test valid?

85% HR Predicted HR max

70% HRR

Volitional fatigue

APHRM healthy

207 - (0.7 x age)

APHRM modified

164 - (0.7 x age)

What should be done before testing CRF?

HR/BP in SUPINE and EXERCISE POSITION

Explain BORG 20 RPE scale

Equipment explain

Demonstrate and practice

During test?

HR - 2x during last 2-3 min of each stage and steady state reached before next stage

BP / RPE - last minute of stage,physical appearance and symptoms

Recovery period

WHICH EVER COMES FIRST

Decrease work rate until HR and BP CONSTANT NOT BACK TO NORMAL

5 minutes

Stop test for these symptoms

Angina

Dyspnea/wheezing

Leg cramps

Dizziness

Stop tests for these signs

Confusion

Unsteady/staggering gait

Pale or blue skin or nailbed

Nausea

Cold/clammy skin

Blood pressure stop signs

Drop in SBP with increase in work rate

SBP falls below pretest

SBP greater then 250 mmHg

DBP greater than 115 mmHg

HR stop signs

does not inc with exercise intensity

change in heart rhythym