Transcript Common Non-Invasive Tests

Lesson Four
COMMON NONINVASIVE
DIAGNOSTIC TESTS
CHAPTER 24
The ECG Paper
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Horizontally
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One small box - 0.04 s
One large box - 0.20 s
Vertically
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One large box - 0.5 mV
The ECG Paper (cont)
3 sec
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
3 sec
Every 3 seconds (15 large boxes) is
marked by a vertical line.
This helps when calculating the
heart rate.
The 12-Leads
The 12-leads include:
–3 Limb leads
(I, II, III)
–3 Augmented leads
(aVR, aVL, aVF)
–6 Precordial leads
(V1- V6)
Views of the Heart
Some leads get
a good view of
the:
Anterior portion
of the heart
Inferior portion
of the heart
Lateral portion
of the heart
ST Elevation
One way to
diagnose an
acute MI is to
look for
elevation of
the ST
segment.
Anterior View of the Heart
The anterior portion of the heart is best
viewed using leads V1- V4.
Rate Rhythm Axis Intervals
Hypertrophy Infarct
Right atrial enlargement

Take a look at this ECG. What do you notice about the P waves?
The P waves are tall, especially in leads II, III and avF.
Ouch! They would hurt to sit on!!
SUMMARY Rate Rhythm Axis Intervals Hypertrophy Infarct
Infarct: Are there T wave
changes?
No
Rhythm Summary
Rate
 Regularity
 P waves
 PR interval
 QRS duration
Interpretation?
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90-95 bpm
regular
normal
0.12 s
0.08 s
Normal Sinus Rhythm
Rhythm #1
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•
•
•
•
Rate?
Regularity?
P waves?
PR interval?
QRS duration?
30 bpm
regular
normal
0.12 s
0.10 s
Interpretation? Sinus Bradycardia
Rhythm #2
•
•
•
•
•
Rate?
Regularity?
P waves?
PR interval?
QRS duration?
130 bpm
regular
normal
0.16 s
0.08 s
Interpretation? Sinus Tachycardia
Rhythm #3
•
•
•
•
•
Rate?
Regularity?
P waves?
PR interval?
QRS duration?
70 bpm
occasionally irreg.
2/7 different contour
0.14 s (except 2/7)
0.08 s
Interpretation? NSR with Premature Atrial
Contractions
PVCs
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Deviation from NSR
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Ectopic beats originate in the ventricles
resulting in wide and bizarre QRS
complexes.
When there are more than 1 premature
beats and look alike, they are called
“uniform”. When they look different, they
are called “multiform”.
1st Degree AV Block
 Deviation

from NSR
PR Interval
> 0.20 s
2nd Degree AV Block, Type I
 Deviation
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from NSR
PR interval progressively lengthens,
then the impulse is completely
blocked (P wave not followed by
QRS).
3rd Degree AV Block
 Deviation

from NSR
The P waves are completely blocked
in the AV junction; QRS complexes
originate independently from below
the junction.
ELECTROCARDIOGRAPHY
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The ECG / EKG.
The tracing given by the evaluation
of electrical impulses generated by
the heart during depolarization
(contraction) and repolarization
(relaxation).
ELECTROCARDIOGRAPHY
USED IN THE EVALUATION OF
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CHEST PAIN - ISCHEMIA VS.
INFARCTION.
RHYTHM DISTURBANCES /
ARRHYTHMIAS.
DRUG TOXICITY – digitalis, quinidine.
METABOLIC EFFECTS – electrolytes, hyper
and hypokalemia, calcium, magnesium.
CONDUCTION DEFECTS – heart block(s).
HOLTER MONITOR
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An ambulatory electrocardiograph.
Used to detect / evaluate arrhythmias
that are episodic.
Also used to assess response to
treatment.
ELECTROENCEPHALOGRAPHY
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The EEG.
Records electrical activity of the brain, mainly the
superficial layers of the cortex.
Used to detect foci of abnormal activity, such as in
epilepsy.
ALSO: brain death, sleep studies (the “somnogram”),
sleep apnea, narcolepsy, etc
ELECTROMYELOGRAPHY
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THE EMG – measures electrical
activity of muscle.
Used to evaluate neuromuscular
disorders, to differentiate between
neuropathy (primary disease of
motor neurons, such as polio), and
myopathy
(primary disease of
muscle, such as myesthenia gravis).
Normal recruitment pattern
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. (A) With minimal effort: a single
motor unit is seen firing at 6 Hz.
The time between 2 discharges is
approximately 166 milliseconds
(ms),
(B) Gradual increase in muscle
strength results in recruitment of
a second motor unit. In this
example, it is 12 Hz, the
reciprocal of the recruitment
interval, which is 85 ms.
(C) With further increase in
muscle strength, a third motor
unit is recruited.
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Amyotphic Lateral Sclerosis:
rapid firing unit
myositis, many motor units are activated
simultaneously at a low level of muscle
contraction. Note the low amplitude and
short duration of individual units.
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45-year-old man presented with a 6-month
history of progressive muscle weakness.
Atrophy of several leg muscles and intrinsic
hand muscles accompanied by occasional
fasciculations but no sensory loss. The
recording is from the anterior tibial muscle.
The motor unit firing at about 25 Hz indicates decreased
recruitment as in a neurogenic disorder. The most likely cause
in this setting of widespread motor involvement without
sensory findings is a motor neuron disorder or motor
neuropathy.
PULMONARY FUNCTION TESTS
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The PFT’s.
Assessment of inspiration and expiration
to determine if a respiratory problem is
due to an obstructive defect, a restrictive
defect, or both.
OBSTRUCTIVE- an increase in airway
resistance; Ex: asthma, COPD.
RESTRICTIVE- a limitation of chest
expansion; Ex: pulmonary fibrosis,
muscular dystrophy, obesity, severe
scoliosis.
PULMONARY FUNCTION TESTS
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See text re the various parameters, the
FVC, the FEV-1, etc.
The Alveolar Sac
PEAK FLOW TESTING
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A hand-held gizmo used in ambulatory
monitoring of air flow in patients w/
asthma.
Monitors expiratory capacity, and can be
plotted on a daily basis to assess for
decreased flow.
Is a sensitive monitor of increased
resistance, and can show a change before
a patient becomes symptomatic.
Can thus be used for intervention prior to
a full-blown flare-up.

http://www.mayoclinic.com/health/asthma/MM00399
Peak Expiratory Flow (liters per
minute)
Age
(Years)
HEIGHT
Age
(Years)
HEIGHT
60”
65”
70”
75”
80”
55”
60”
65”
79”
75”
20
554
602
649
693
740
20
390
423
460
496
529
25
543
590
636
679
725
25
385
418
454
490
523
30
532
577
622
664
710
30
380
413
448
483
516
35
521
565
609
651
695
35
375
408
442
476
509
40
509
552
596
636
680
40
370
402
436
470
502
45
498
540
583
622
665
45
365
397
430
464
495
50
486
527
569
607
649
50
360
391
424
457
488
55
475
515
556
593
634
55
355
386
418
451
482
60
463
502
542
578
618
60
350
380
412
445
475
65
452
490
529
564
603
65
345
375
406
439
468
70
440
477
515
550
587
70
340
369
400
432
461
Peak Expiratory Flow Rate
NORMAL CHILDREN AND
ADOLESCENTS
HEIGHT
(INCHES)
MALES &
FEMALES
HEIGHT
(INCHES)
MALES &
FEMALES
HEIGHT
(INCHES)
MALES &
FEMALES
43
147
51
254
59
360
44
160
52
267
60
373
45
173
53
280
61
387
46
187
54
293
62
400
47
200
55
307
63
413
48
214
56
320
64
427
49
227
57
334
65
440
50
240
58
347
66
454
UREA BREATH TEST FOR H. pylori
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H. pylori the cause of many cases of gastritis
and peptic ulcer.
If detected, can be eradicated and disease
healed.
H. pylori produces an urease, an enzyme that
breaks down urea, creating CO2 that is
absorbed from the GI tract then exhaled.
Test measures changes in CO2 from baseline to
after patient is given synthetic urea.
Serologic (antibody) tests exist, but can not
differentiate between current and prior
infection.
CHAPTER 26
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STRESS TESTS.
CARDIAC CATH.
ELECTROPHYSIOLOGIC STUDIES.
SYNCOPE TESTS.
STRESS TESTS
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See
http://www.emedicine.com/med/to
pic2961.htm
For an excellent, comprehensive
review of exercise stress testing.,
STRESS TESTS
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A test in which a patient exercises
on a treadmill, thereby increasing
cardiac demand for oxygen while
oxygen consumption in skeletal
muscle increases.
EKG monitoring is done, looking for
evidence of ischemia, ie ST segment
depression.
STRESS TESTS
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USED FOR
1) Assessment of probability of and
extent of coronary artery disease (CAD).
2) Estimate prognosis in patients w/ CAD.
3) Determine functional capacity.
4) Assess the effects of therapy.
5) Assess need for cardiac cath and / or
coronary revascularization.
STRESS TESTS
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Mortality – your text says 1 death per
10,000 procedures; eMedicine web site
says 1 per 2500. Either way, not a 100%
benign study.
Sometimes used in conjuction w/
thallium radionuclide study, whereby
post-exercise scans are used to assess
myocardial perfusion. The “Thallium
Stress Test” or “Thallium Treadmill.”
CARDIAC CATHETERIZATION
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Catheterization of the left side of the
heart via the femoral artery, or the right
side of the heart via the IVC. Dye is
injected to assess anatomy of the heart
and patency of the coronary arteries.
If aortic stenosis is present the left heart
can be assessed from the right heart via
the “trans-septal” technique in which a
needle injects the dye thru the
interventricular septum.
Measurements are taken of pressure to
assess flow, and O2 to assess
oxygenation.
CARDIAC CATHETERIZATION
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USES
Assess cardiac malformations – congenital
and acquired such as valvular defects.
Assess need for coronary
revascularization, which can be done at
the same time via balloon angioplasty, or
later via CABG.
OCCLUSION OF THE L.A.D.
ELECTROPHYSIOLOGIC STUDIES
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A type of cardiac cath in which
electrodes are used to assess
cardiac conduction.
Can locate the focus of aberrant
conduction pathways.
Can be used for diagnostic as well
as therapeutic purposes, such as
treatment of tachyarrhythmias.