ECG
description
Transcript of ECG
![Page 1: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/1.jpg)
Dr. Bernhard Arianto Purba, M.Kes., AIFO
ECG
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Textbooks• Guyton, A.C & Hall, J.E. 2006. Textbook of Medical
Physiology. The 11th edition. Philadelphia: Elsevier-Saunders: 918-930, 961-977.
• Brooks, G.A. & Fahey, T.D. 1985. Exercise Physiology. Human Bioenergetics and Sts Aplications. New York : Mac Millan Publishing Company: 122-143.
• Foss, M.L. & Keteyian, S.J. 1998. Fox’s Physiological Basis for Exercise and Sport. 4th ed. New York : W.B. Saunders Company: 471-491.
• Astrand, P.O. and Rodahl, K. 1986. Textbook of Work Pysiology, Physiological Bases of Exercise. New York : McGraw—Hill.
• Braunwald, Pauci, et al.2008. Harrison's PRINCIPLES OF INTERNAL MEDICINE. Seventeenth Edition. New York : McGraw—Hill: Chapter 332, 333, 338.
• Jardins, Terry Des. 2002. Cardiopulmonary Anatomy & Physiology. The 4th edition. USA: Delmar, A Division of Thomson Learning Inc.
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ELECTROCARDIOGRAPHY
(ECG)
![Page 4: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/4.jpg)
ECG
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A Brief introduction to ECG
• The electrocardiogram (ECG) is a time-varying signal reflecting the ionic current flow which causes the cardiac fibers to contract and subsequently relax. The surface ECG is obtained by recording the potential difference between two electrodes placed on the surface of the skin. A single normal cycle of the ECG represents the successive atrial depolarisation/repolarisation and ventricular depolarisation/repolarisation which occurs with every heart beat.
• Simply put, the ECG (EKG) is a device that measures and records the electrical activity of the heart from electrodes placed on the skin in specific locations
![Page 6: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/6.jpg)
What the ECG is used for?
• Screening test for coronary artery disease, cardiomyopathies, left ventricular hypertrophy
• Preoperatively to rule out coronary artery disease• Can provide information in the precence of metabolic
alterations such has hyper/hypo calcemia/kalemia etc.• With known heart disease, monitor progression of the
disease• Discovery of heart disease; infarction, coronal
insufficiency as well as myocardial, valvular and cognitial heart disease
• Evaluation of ryhthm disorders• All in all, it is the basic cardiologic test and is widely
applied in patients with suspected or known heart disease
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![Page 8: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/8.jpg)
Each small box = 1 mm = .04 Sec.5 small boxes = 1 large box = 0.2 Sec.
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MEASURING ECG ECG commonly measured via 12
specifically placed leads
![Page 10: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/10.jpg)
Lead Configurations for ECG Measurement
Bipolar Leads Augmented Leads Chest (V) Leads
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Bipolar Leads: lead I
+ _
vo+
_
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Bipolar Leads: lead II
+ _
vo+
_
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Bipolar Leads: lead III
+ _
vo+
_
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ECG Limb Leads
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Augmented Leads: aVR
+ _
vo+
_
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Augmented Leads: aVL
+ _
vo+
_
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Augmented Leads: aVF
+ _
vo+
_
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ECG Augmented Limb Leads
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Unipolar Chest Leads
v1 v2
v3
v4
v5 v6
v1: fourth intercostal space, at right sternal margin. v2: fourth intercostal space, at left sternal margin. v3: midway between v3 and v4. v4: fifth intercostal space, at mid clavicular line. v5: same level as v4, on anterior axillary line. v6: same level as v4, on mid axillary line.
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Unipolar Chest Leads (cont.)
+ _ +
_
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ECG Precordial Leads
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Current Lead Placement Conventions(22 Electrodes)
V3R
V4RV5RV6R
E
H
I
3R
5R
V9V8
V7
I
E
M
6R
Current clinical conventions may use 22 different leads
![Page 25: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/25.jpg)
ECG Lead Color Codes
C (brown)
LA (black)
LL (red)RL (green)
RA (white)
![Page 26: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/26.jpg)
Surface Cardiac Potentials
taken at t = to suggests an equivalent dipole located within the heart
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Eindhoven’s Triangle-very crude solution to inverse problem using bipolar limb leads:
RA LA
LL
_
_
+
_
++
lead II
lead I
lead III
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NORMAL HEARTBEAT AND ATRIAL ARRHYTHMIA
Normal rhythm Atrial arrhythmia
AV septum
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Ventri-culardepola-rization
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Ventri-culardepola-rization(cont’d)
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Ventri-culardepola-rization(cont’d)
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++
++
++
++ + +
++
++
++
++
++
--
--
--
- ---
--
-
--
--
--
--
--
-
Ventri-cularrepola-rization
![Page 33: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/33.jpg)
Lead I
![Page 34: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/34.jpg)
Lead II
![Page 35: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/35.jpg)
Lead III
![Page 36: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/36.jpg)
LimbLeads(bipolar)
Lead I
Lead II
Lead III
![Page 37: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/37.jpg)
aVR
![Page 38: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/38.jpg)
aVL
![Page 39: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/39.jpg)
aVF
![Page 40: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/40.jpg)
aVR
aVL
aVF
Uni-polarLead
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Normalvalues
PR interval0.12-0.20”
P wave00.8-0.11”
QRS duration0.06-0.10”
Intrinsicoid deflection
< 0.05”
U wave
ST segmentStd: > 1mmPre : > 2mm
T wave
QT segmentMen < 0.39”Wo < 0.40”
![Page 42: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/42.jpg)
Pre-cordialleads
V1 V2V4
V5
V3
V6
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Hori-zontalvsVerti-cal heart
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Hori-zontalvsVerti-cal heart
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Clock-wisevsCounterclock-wiserotation
Viewed from below the heart looking towards the apex in vertical heart
13
24
13 24
13
24
1
3
24
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P wave
V1
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AtrialEnlargement
V1
P mitralWide and notch
Biphasic with(-) terminalcomponent
Left atrialenlargement
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AtrialEnlargement(cont’d)
V1
Tall and peakedP wave
Right atrialenlargement
Tall and peakedP wave
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Elec-tricalaxis
Lead I
aVF
qRS = +3
qRS = +1
![Page 50: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/50.jpg)
TheQRS
Bundle of His
LBB
Anterosuperiordivision
Posteroinferiordivision
RBB
![Page 51: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/51.jpg)
TheQRS
13
2
V1
V6
4
QRS vectors:• Initial depolarization• Terminal depolarization• S-T segmen• Re-polarization
![Page 52: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/52.jpg)
Myo-cardial injury
Electrical forces are directed away from a injured area
A B C D E
Normal Minimal Subendocard Transmural Subepicard
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Myo-cardial injury
A B C D E
Normal Minimal Subendocard Transmural Subepicard
ST segment deviated towards the surface of injured tissue
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Myo-cardialinfarction
Zones of myocardial infarction:• Necrosis• Injury• Ischaemia
2
13 1
2
34
12
3
4
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Myo-cardialinfarction(cont’d)
ECG parameters of myocardial infarction:• Necrosis• Injury• Ischaemia
13
V1
V6
24
![Page 56: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/56.jpg)
Myo-cardialinfarction(cont’d)
Phases of myocardial infarction:
• Hyperacute phase- Slope elevation of the ST sement- Tall widened T wave- Increased ventr. activation time
• Fully evolved phase- Pathological Q wave- Coved, elevated ST segment- Inverted symetrical T wave
• Old infarction- Pathological Q wave- ST segment and T wave return to normal
![Page 57: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/57.jpg)
Myo-cardialinfarction(cont’d)
Localization of infarcted areas
2
13
II, III, aVF
IaVLV4 V5
V6
V1 V2
V3
![Page 58: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/58.jpg)
Rightventricularhypertrophy
12
V1
V6
4
3
![Page 59: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/59.jpg)
Leftventricularhypertrophy
12
V1
V6
4
3
Diatolic overload
![Page 60: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/60.jpg)
Leftventricularhypertrophy
12
V1
V6
4
3
Systolic overload
![Page 61: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/61.jpg)
RBBB
12
V1
V6
4
3
![Page 62: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/62.jpg)
LBBB
1a2
V1
V6
43
1b
![Page 63: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/63.jpg)
QTinterval
QTc= QT
R-R
Prolonged QTc• Hypocalcemia• Acute rheumatic carditis
Shortened QTc
• Hypercalcemia• Digitalis effect• Hyperthermia• Vagal stimulation
Normal QT does not exclude the diagnosis of
• Acute myocardial infarction• Acute myocarditis of any causes• Sympathetic stimulation• Procain effect
![Page 64: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/64.jpg)
AtrialSeptalActiva-tion
Sinus rhythms• Sinus arrythmia• Sinus tachycardia• Sinus bradycardia
AV nodal rythms• AVn extrasystole• Paroxysmal AVn tachycardia• Idionodal tachycardia
Ectopic atrial rythms• Atrial extrasystole• PAT• Atrial fibrilation• Atrial flutter
Ventricular rhytms• V-extrasystole• V-tachycardia• V-flutter• V-fibrilation• Idioventricular tachycardia
Disturbances of impulse formation
![Page 65: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/65.jpg)
Arrhythmias
Disturbances of impulse conduction
S-A blockA-V block
WPW syndrome(Wolf-Parkinson-White)LGL syndrome(Lawn-Ganong-Levin)
Reciprocal rythms
![Page 66: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/66.jpg)
Arrhythmias
2nd disorders of rythms
Atrial escape
Ventricular escape
AVn escape
A-V dissociation
Aberrant ventricular conduction
![Page 67: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/67.jpg)
Arrhythmias
Diagnostic approach
To be continued next weekInsyaa Allah
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Arrhythmias
12
V1
V6
4
3
![Page 69: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/69.jpg)
Arrhythmias
12
V1
V6
4
3
![Page 70: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/70.jpg)
Arrhythmias
12
V1
V6
4
3
![Page 71: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/71.jpg)
Arrhythmias
12
V1
V6
4
3
![Page 72: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/72.jpg)
Arrhythmias
12
V1
V6
4
3
![Page 73: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/73.jpg)
Electrocardiogram
The WavesP wave
atrial depolarization
duration 0.11s
amplitude < 3mm
detects atrial functionSA node
![Page 74: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/74.jpg)
Electrocardiogram
The WavesQRS Complex
ventricular depolarization duration 0.10s
detects ventricular functionQ wave
first downward strokeR wave
first upward strokeS wave
any downward stroke preceded by an upward stroke
T waveventricular repolarization
![Page 75: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/75.jpg)
Intervals and Segments
PR segmentend of P wave to start of
QRSmeasures time of
depolarization through AV node
PR intervalstart of P wave to start of
QRSmeasures time from start of SA conduction to end of
AV node conductionnormal 0.12-0.20s
![Page 76: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/76.jpg)
Intervals and Segments
ST segmentend of QRS complex to start
of T wavemeasures start of ventricular
repolarizationelevated in MI’s
ST intervalend of QRS to end of T waverepresents complete time of
ventricular repolarization
QT intervalstart of QRS to end of T wave
duration of ventricular systole
< 1/2 of the RR interval
![Page 77: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/77.jpg)
Intervals and Segments
Intervalsthe timing for
depolarizations/repolarizations can be interpreted from the EKG
P-R 0.12-0.2 secmeasures the time between the start
of atrial depolarization and the start of ventricular depolarization
a long P-Q interval is a sign of AV node dysfunction
QT interval, about 0.4 secstart of QRS to end of T wave
QRS 0.08-0.1 secwider with ventricular dysfunction
ST segment (don’t worry about time)elevated with acute MI
![Page 78: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/78.jpg)
Electrocardiogram
The wavesmore on the QRS
note that the Q or the R or the S wave is not always
presentname according to direction
of first deflection, second, etcQ waves are often absent
lead V1no Q
small Rlarge S
lead V2no Q
large Rsmall S
![Page 79: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/79.jpg)
Heart Rate
Heart Ratedefined as beats per
minuteeasy way to estimate ratefind an R wave on a thick
linecount off on the thick
lines 300, 150, 100, 75, 60,
50until you reach another
R wave
in our example the middle R wave falls on the dark
linethe next R falls just before the 75, so
estimate about 80 bpm
300
15010075
![Page 80: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/80.jpg)
Normal Sinus Rhythmheart rate between 60-100
bpm pacing by SA node.
QRS after every P waverhythm is regular
Sinus Tachycardiaheart rate > 100 bpm
p wave is there but hidden by the T wave
regular QRS rhythmSinus Bradycardiaheart rate < 60 bpm
QRS after every P waveregular rhythm
Heart Rate
![Page 81: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/81.jpg)
ST segment elevation
ischemia
Q wavein some leads may indicate ischemia and
necrosis
T wave inversionlate sign of
necrosis and fibrosis
Wave Abnormalities
![Page 82: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/82.jpg)
Atrial Fibrillationmultifocal areas in atria firing
no p waves and irregular heart rate
Rhythm Abnormalities
![Page 83: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/83.jpg)
Complete (3rd degree) AV Block AV node cannot conduct impulsep waves and QRS not connected
irregular heart rate
Rhythm Abnormalities
![Page 84: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/84.jpg)
Premature Ventricular Contractionsventricles pace early
early heart beatlarge QRS
Rhythm Abnormalities
![Page 85: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/85.jpg)
Ventricular Tachycardiarapid ventricular pacing
rapid, regular ratewide QRS
Rhythm Abnormalities
![Page 86: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/86.jpg)
Ventricular Fibrillationmultifocal
ventricular beatsirregular
won’t last long
Rhythm Abnormalities
![Page 87: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/87.jpg)
0
+90
180
-90
Axis
QRS AXISanother name for the vector of
depolarizationan axis is measured in degrees the axis is measured by adding
the positive deflection and subtracting the negative
deflectionoverall + is left axis directionoverall - is right axis direction
for lead one most of the QRS is positive, therefore it has a
leftward axisif an MI caused the QRS to be
mostly negative the lead would have a rightward axis
— +
![Page 88: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/88.jpg)
QRS AXISlead II
positive on left legnegative on right arm
looking at the tracing we see that the QRS is
mostly positivewhat does this mean?0
+90
180
-90
—
+
Axis
![Page 89: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/89.jpg)
QRS AXISlead III
positive on left legnegative on left arm
looking at the tracing we see that the QRS is
mostly positivewhat does this mean?0
+90
180
-90
—
+
Axis
![Page 90: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/90.jpg)
QRS AXISlead I
leftward axislead II
downward axisfrom this we can see that a
normal QRS axis lies somewhere in between 0 and +90 degrees
remember that infarction will cause the axis to shift rightward
(>+90) and that hypertrophy will shift the axis upward
(between 0 and -90)
0
+90
180
-90
—
+
+
Axis
![Page 91: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/91.jpg)
The Anatomy of the Heart
The Blood Supply to the Heart• Coronary circulation meets heavy demands
of myocardium for oxygen, nutrients• Coronary arteries (right, left) branch from
aorta base• Anastomoses (arterial interconnections)
ensure constant blood supply• Drainage is to right atrium
• Great, middle cardiac veins drain capillaries• Empty into coronary sinus
![Page 92: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/92.jpg)
• Arteries include the right and left coronary arteries, marginal arteries, anterior and posterior interventricular arteries, and the circumflex artery
• Veins include the great cardiac vein, anterior and posterior cardiac veins, the middle cardiac vein, and the small cardiac vein
Blood Supply to the Heart
![Page 93: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/93.jpg)
SA node activity and atrial activation begin.
Stimulus spreads across the atrial surfaces and reaches the AV node.
There is a 100-msec delay at the AV node. Atrial contraction begins.
The impulse travels along the interventricular septum within the AV bundle and the bundle branches to the Purkinje fibers.
The impulse is distributed by Purkinje fibers and relayed throughout the ventricular myocardium. Atrial contraction is completed, and ventricular contraction begins.
Time = 0
SA node
AV node
Elapsed time = 50 msec
Elapsed time = 150 msec
AV bundle
Bundle branches
Elapsed time = 175 msec
Elapsed time = 225 msec Purkinje fibers
![Page 94: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/94.jpg)
Coronary Circulation
![Page 95: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/95.jpg)
Coronary Circulation
![Page 96: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/96.jpg)
Coronary Circulation
Figure 20.9a, b
![Page 97: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/97.jpg)
Coronary Circulation
Figure 20.9c, d
![Page 98: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/98.jpg)
HOLTER MONITOR
Technology• 5 electrodes• 2-3 leads• Derived 12 lead available• Digital or analog recording• Digital transmission to analyzer• Requires removal of Holter monitor to
scan recording
![Page 99: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/99.jpg)
Uses:• Patients experiencing daily symptoms• Precise quantification of arrhythmias
Positives:• 24-48 hours full disclosure available• Heart rate and AF burden graphs• Arrhythmia counts (ex., 10 PVCs per
hour)
HOLTER MONITOR
![Page 100: ECG](https://reader036.fdocuments.in/reader036/viewer/2022070422/56816582550346895dd825c7/html5/thumbnails/100.jpg)