ELECTROCARDIOGRAM
Graphic representation of the electrical
currents of the heart
Electrodes- standard position in the chest
and limbs
LEADS:
o 12-Lead
o 15-Lead
o 18-Lead
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T wave
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Atrial Repolarization
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LEAD
Electrodes create imaginary lines.
Reference point from which the electrical
activity is viewed.
ECG waveforms represent electrical
impulse in relation to the lead.
Not visible
Same time with ventricular depolarization
U wave
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How to get ECG?
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Ventricular depolarization
Repolarization of Purkinje fibers
Sign of Hypokalemia
Smaller than P wave
PR Interval
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Beginning of P wave to beginning of QRS
complex
ST Segment
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Early ventricular repolarization
Sign of cardiac ischemia
QT Segment
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Total time for ventricular depolarization
and repolarization.
TP Interval
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End of T wave to beginning of next P
wave.
PP Interval
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Atrial rate and rhythm
RR Interval
P-Wave
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Atrial depolarization
QRS Complex
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Ventricular depolarization
Q-wave- 1st negative deflection
R wave- 1st positive deflection after P
wave
S wave- 1st negative deflection after R
wave
Ventricular rate and rhythm
Affected by:
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Age
Gender
BP
Height
Weight
Symptoms
Medications
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Electrical impulse starts at a regular rate
and rhythm in the SA node and travels
through the normal conduction pathway.
Rate: 60-100 bpm
Conduction- electrical impulse from SA
node to AV node.
60-100 bpm
Depolarization- electrical stimulation
Systole- mechanical contraction
Repolarization- electrical relaxation
Diastole- mechanical relaxation
SA node electrical impulse generation
through ventricular repolarization
completes the electromechanical circuit.
HR and Contractility is controlled by the
Autonomic Nervous System
o Sympathetic Nerve Fibers: adrenergic
fibers, heart, and arteries. Stimulation
creates positive chronotropy (HR),
dromotropy (conduction), inotropy
(contraction).
o Parasympathetic Nerve Fibers: heart and
arteries. Stimulation creates negative
chronotropy, dromotropy, and inotropy.
*Increased sympathetic stimulation=increased
arrythmia
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Disorders of the formation or conduction
(or both) of the electrical impulse of the
heart.
Heart rate, heart rhythm, or both.
Originates from foci within the atria.
Not from SA node
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Starts in the atrium before the next
normal impulse of the SA node.
Rate: depends on the underlying rhythm
Early P waves, followed by QRS but it may
also be absent.
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Originates in the SA node.
Sinus bradycardia, sinus tachycardia,
sinus arrythmia
Faster than normal rate
Rate: >100 bpm but <120 bpm
Causes: physiologic or psychologic stress,
medications, inappropriate sinus
tachycardia, autonomic dysfunction
Management: vagal maneuvers,
synchronized cardioversion
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*Decreased sympathetic stimulation=
decreased arrythmia
Arrythmia
Slower than normal rate
Rate: <60 bpm
Rhythm: regular
Causes: stimulation of vagus nerve,
medications, significant hemodynamic
effect
Management: 0.5 mg Atropine
Very common arrythmia
Associated w/ aging
Rapid, disorganized, and uncoordinated.
Highly irregular rhythm
Symptoms: asymptomatic, palpitations,
HF symptoms
Risk Factors: HF, MI, Embolic events
MGT: anti-thrombotic medications, betablockers and CCBs, and electrical
cardioversion
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Conduction defect in the atrium
Rapid, regular atrial impulse
Symptoms: chest pain, SOB, Low BP
MGT: vagal maneuvers, adenosine, antithrombotic therapy, rate and rhythm
control, electrical cardioversion.
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Flatline
No heartbeat, no palpable pulse, no
respirations
MGT: high quality CPR
Originates from the ventricles.
Ventricular asystole- absence of rhythm
formation
Starts in the ventricles and conducted
through the ventricle before the next
sinus impulse.
Can occur in healthy individuals.
Irregular rhythm
Risks: Caffeine, alcohol, or nicotine
intake, cardiac ischemia, digitalis toxicity,
electrolyte imbalance (hypokalemia),
increased workload of the heart
MGT: amiodarone, beta-blockers
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AV blocks
Conduction of the impulse through the
AV node to the bundle of His area are
decreased or stopped.
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All atrial impulse through the AV node
into the ventricles are slower than normal
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all but one of a series of atrial impulses
are conducted through the AV node into
the ventricles.
́ Repeating pattern
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Risks: coronary disease, acute MI,
untreated VT, cardiomyopathy, valvular
heart disease
MGT: Early defibrillation, CPR until
defibrillation is available
Emergency
3 or more PVCs in a row
Unresponsive and pulseless
MGT: anti-arrhythmic medications,
cardioversion, defibrillation (treatment of
choice)
Most common arrythmia in px w/ cardiac
arrest
No atrial activity
No coordinated cardiac activity, cardiac
arrest, and death
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Only some of the atrial impulses are
conducted through the AV node into
ventricles.
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No atrial impulse is conducted through
the AV node into the ventricles
Atrial electrical activity not conducted to
the ventricles
AV dissociation
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VALVULAR PROBLEMS
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Assessment & Diagnostic: auscultation
(systolic murmur), ECG
MGT: ACE inhibitors, angiotensin receptor
blockers, direct arterial dilators, betablockers, mitral valvuloplasty, valve
replacement
Regurgitation
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Backward flow of blood because the
valve affected doesn’t close properly.
Aka leaking heart valve or insufficiency.
Prolapse- involves a leaflet flopping or
bulging backward. Tends to occur in the
mitral valve.
Stenosis
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Occurs when a valve’s leaflets get thick
or stiff or stuck together.
Happens when valves do not open
completely.
Results to reduced blood flow through
the valve.
Atresia
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Valve is missing.
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Blood flows from the left ventricle back
into the left atrium during systole.
The edges of the mitral valve leaflets do
not close completely during systole
because the leaflets and the chordae
tendineae have thickened and became
fibrotic, causing abnormal contraction.
Clinical Manifestations: dyspnea, fatigue,
weakness, palpitations, SOB on exertion,
cough
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Ballooning stretches the leaflet to the
point that the valve does not remain
closed during systole. Blood then
regurgitates from the LV into the LA.
Can cause heart enlargement, atrial
fibrillation, pulmonary hypertension, or
heart failure.
Clinical Manifestations: fatigue, SOB,
syncope, palpitations, chest pain,
lightheadedness, dizziness
Assessment & Diagnostic: clinical signs of
HF, Auscultation (mitral click, murmur),
ECG
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MGT: antiarrhythmics, nitrates, calcium
channel blockers, or beta-blockers (if with
chest pain), mitral valve repair or
replacement
calcium-channel blockers (control of
ventricular rate), cardioversion,
valvuloplasty, commissurotomy.
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Narrowing or blockage of the mitral valve
of the heart, causing the blood not to
flow from LA to LV
Usually caused by rheumatic fever and
will show up years later.
Manifestations: dyspnea on exertion,
progressive fatigue, decreased exercise
tolerance, dry cough or wheezing,
hemoptysis, palpitations, orthopnea,
PND, arrythmia
Assessment & diagnostic: clinical signs of
HF, auscultation (murmur), ECG, Echo,
exercise testing, cardiac catheterization
w/ angiography
Prevention: rheumatic heart disease,
acute rheumatic fever
MGT: manage signs of CHF,
anticoagulants, beta-blockers, digoxin or
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Aortic valve does not close completely,
causing the blood to backflow from the
aorta into the LV.
Clinical manifestations: Pounding or
forceful heartbeat, fatigue, visible or
palpable arterial pulsations, SOB,
orthopnea, PND, Dyspnea on exertion
Assessment & diagnostic: water hammer
(Corrigan’s) pulse, auscultation (highpitched, blowing diastolic murmur), ECG,
MRI, Cardiac catheterization
MGT: manage signs of CHF,
antiarrhythmics, ACE inhibitors & calciumchannel blockers (HPN), aortic valve
replacement or valvuloplasty
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Aortic valve narrows and blood cannot
flow normally
Clinical manifestations: dyspnea on
exertion, orthopnea, PND, pulmonary
edema, dizziness, syncope, angina
pectoris, low BP, low pulse pressure
Assessment & diagnostic: palpable
vibration, auscultation (loud, harsh
systolic murmur. Low pitched, crescendodescrescendo, rough, rasping, and
vibrating, S4), Cardiac imaging, ECG,
Stress test
MGT: manage signs of left ventricular
failure and arrythmia, Transcatheter
Aortic Valve Replacement (TAVR),
balloon percutaneous valvuloplasty
Nursing Management:
Health Education:
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Diagnosis
Progressive nature of dx
Tx plan
Possible infections and complications
Minimize risk of developing IE
Report new symptoms or any changes
Assessment:
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VS
Heart and lung sounds
Peripheral pulses
s/sx of HF, arrythmia, etc