Defibrillation is a medical procedure used to treat life-threatening heart rhythm disturbances such as ventricular fibrillation and pulseless ventricular tachycardia by administering electric shocks to the heart. Developed in the late 19th century, modern variations include implantable cardioverter-defibrillators and automated external defibrillators, with biphasic defibrillators being more effective and safer than monophasic types. Proper ECG interpretation is crucial for diagnosing various cardiac conditions, using techniques to assess heart rate, rhythm, and potential arrhythmias.

1. DEFIBRILLATIO
N
By: Ms. JOYCE WILSON
HFCON

2. DEFIBRILLATION
Defibrillation is non synchronized random administration of
shock during a cardiac cycle.
It is a medical technique used to counter the onset of
ventricular fibrillation, a common cause of cardiac
arrest, and pulseless ventricular tachycardia.
In simple terms, the process uses an electric shock to stop
the heart arrhythmias, in the hope that the heart will restart
with rhythmic contractions.

3. HISTORY OF
DEFIBRILLATION
Defibrillation was invented in 1899 by Prevost
and Batelli, two Italian physiologists. They
discovered that electric shocks could convert
ventricular fibrillation to sinus rhythm in dogs.
The first case of a human life saved by
defibrillation was reported by Beck in 1947.

4. THE PURPOSE OF
DEFIBRILLATION
Is to apply a controlled electrical
shock to the heart, which leads to
depolarization of the entire electrical
conductive system of the heart.

5. During defibrillation electrical current travels from the
negative to the positive electrode by traversing
myocardium.
It causes all of the heart cells to contract
simultaneously. This interrupts and terminates
abnormal electrical rhythm. This, in turn, allows the
sinus node to resume normal pacemaker activity.

6. TYPES OF DEFIBRILLATORS
INTERNAL DEFIBRILLATORS
The device may be implanted directly in the user of the
device.
So it is known as an Impalantable cardioverter-
defibrillator or (much less frequently) an internal
cardiac defibrillator (ICD).
This type of defibrillator is designed to provide immediate
defibrillation to high-risk patients .

7. Implantable Cardioversion
Defibrillation
An implantable cardioverter-defibrillator (often called an ICD) is
a device that briefly passes an electric current through the
heart. It is "implanted," or put in your body surgically. It includes
a pulse generator and one or more leads. The pulse generator
constantly watches your heartbeat.

8. TYPES OF DEFIBRILLATORS
Automated External defibrillator (AED).
External defibrillators are typically used in hospitals or
ambulances, but are increasingly common outside
the medical areas .
As automated external defibrillators become safer and
cheaper.

9. EXTERNAL
DEFIBRILLATOR

10. In monophasic, there is no ability to adjust for patient
impedance or the resistance to the current exerted
by the patient’s body, and it is generally
recommended that all monophasic defibrillators
deliver 360J of energy in adult patients to ensure
maximum current is delivered in the face of an
inability to detect patient impedance.

11. • Usually the initial voltage applied is higher than the reversed
polarity shock. Biphasic wave forms were initially developed
for use in implantable cardioversion defibrillators (ICD) and
later adapted to external defibrillators. Defibrillators can sense
the thoracic impedance and increase or decrease their
internal resistance so that the selected level of energy is
delivered to the subject.
• Biphasic shocks are more effective than monophasic shocks
and need lesser energy. Typically when 360 Joules are
delivered for defibrillation in a monophasic defibrillator, 200
Joules are given in a biphasic defibrillator.
• This could theoretically reduce the potential damage to the
heart muscle by the high voltage shock.

12. Availability
• Monophasic
defibrillators are less
popular in the current
context.
Availability
• Biphasic defibrillation is
more common
nowadays and used for
implantable as well as
external defibrillators

13. Adjustment for
Patient Impedance
• Monophasic
defibrillator is not able
to adjust the current
according to the
resistance exerted by
the patient’s body.
Adjustment for Patient
Impedance
• Biphasic defibrillators are
capable of changing the
current as per the patient’s
impedance hence known to
be more effective. Different
manufacturers have used
this functionality to produce
different types of biphasic
defibrillators.

14. Strength of the
Current
• Monophasic
defibrillator uses a
fixed current to deliver
360J energy to
terminate cardiac
arrhythmias.
Strength of the Current
• In contrast, biphasic
defibrillators can manually
(shock the patient
with 120-200 Joules) or
automatically adjust the
strength of the current, and
it uses lesser strength than
monophasic defibrillators.

15. Overall Effectively
• Monophasic defibrillators
are less efficient.
Risk of Damaging Heart
Muscles
• Monophasic defibrillator has
a greater risk of damaging
the heart muscle as it
delivers a greater current.
Overall Effectively
• In contrast, biphasic
defibrillators are more
efficient.
Risk of Damaging Heart
Muscles
• Biphasic defibrillator uses
a smaller current and
hence the damage is
minimized.

16. INDICATIONS
• Pulse-less ventricular tachycardia (VT)
• Ventricular fibrillation (VF)

17. A JOYCE’S GUIDE TO
ECG

18. Electrocardiography-
is transthoracic interpretation of
the electrical activity of the heart
over time captured and externally
recorded by skin electrodes for
diagnostic or research purposes
on human hearts.
What is ECG?

19. THE HISTORY OF ECG MACHINE
1903
A Dutch
doctor and physiologist.
He invented the first
practical electrocardiogram and
received the Nobel Prize in
Medicine in 1924 for it
Willem Einthoven
NOW
Modern ECG machine
has evolved into compact
electronic systems that often
include computerized
interpretation of the
electrocardiogram.

20. ECG MACHINES!

21. The graph paper recording produced by the machine is termed an
electrocardiogram,
It is usually called ECG or EKG
STANDARD CALLIBRATION
Speed = 25mm/s
Amplitude =
0.1mV/mm
1mV 10mm high
1 large square  0.2s(200ms)
1 small square 0.04s
(40ms) or 1 mV amplitude

22. 1. Place the patient in a supine or
semi-Fowler's position. If the patient
cannot tolerate being flat, you can do
the ECG in a more upright position.
2. Instruct the patient to place their
arms down by their side and to relax
their shoulders.
3. Make sure the patient's legs are
uncrossed.
4. Remove any electrical devices, such
as cell phones, away from the
patient as they may interfere with the
machine.
5. If you're getting artifact in the limb
leads, try having the patient sit on
top of their hands.
6. Causes of artifact: patient
movement, loose/defective
electrodes/apparatus, improper
grounding.
HOW TO DO ELECTROCARDIOGRAPHY
An ECG with artifacts.
Patient, supine position

23. THE LIMB ELECTRODES
RA - On the right arm, avoiding thick muscle
LA – On the left arm this time.
RL - On the right leg, lateral calf muscle
LL- On the left leg this time.
THE 6 CHEST ELECTRODES
V1 - Fourth intercostal space, right sternal border.
V2 - Fourth intercostal space, left sternal border.
V3 - Midway between V2 and V4.
V4 - Fifth intercostal space, left midclavicular line.
V5 - Level with V4, left anterior axillary line.
V6 - Level with V4, left mid axillary line.
Electrodes
Usually consist of a conducting gel, embedded
in the middle of a self-adhesive pad onto
which cables clip. Ten electrodes are used for a
12-lead ECG.
Placement of electrodes

24. The ECG works mostly by detecting and
amplifying the tiny electrical changes on
the skin that are caused when the heart
muscle "depolarizes" during each heart
beat.
How does an ECG work?

26. The patient
Lying supine
+ wearing sarong

27. Place all theelectrodescorrectly
These are all
electrodes

29. PEOPLE USUALLY REFER THE
ELECTRODES CABLES AS
DUDE,
THAT’S
CONFUSING!
LEAD
S
should be correctly
defined as the tracing
of the voltage
difference between
the electrodes and is
what is actually
produced by the ECG
recorder.
LEADS

30. SO, WHERE ARE THE
LEADS?

31. IIIII
LEADS I, II,
III
THEY ARE FORMED BY VOLTAGE TRACINGS BETWEEN
THE LIMB ELECTRODES (RA, LA, RL AND LL). THESE
ARE THE ONLY BIPOLAR LEADS. ALL TOGETHER THEY
ARE CALLED THE LIMB LEADS OR
THE EINTHOVEN’S TRIANGLE
RA LA
RL LL
I

32. LEADS aVR, aVL,
aVF
THEY ARE ALSO DERIVED FROM THE LIMB ELECTRODES, THEY
MEASURE THE ELECTRIC POTENTIAL AT ONE POINT WITH
RESPECT TO A NULL POINT. THEY ARE THE AUGMENTED LIMB
LEADS
RA LA
RL LL
aVR
aVF
aVL

33. LEADS
V1,V2,V3,V4,V5,
V6
THEY ARE PLACED DIRECTLY ON THE CHEST. BECAUSE
OF THEIR CLOSE PROXIMITY OF THE HEART, THEY DO
NOT REQUIRE AUGMENTATION. THEY ARE CALLED THE
PRECORDIAL LEADS
RA LA
RL LL
V1
V2
V3
V4
V5
V6

34. These leads help to determine heart’s electrical axis. The
limb leads and the augmented limb leads form the frontal
plane. The precordial leads form the horizontal plane.

35. Leads Anatomical representation of the heart
V1, V2, V3, V4 Anterior
I, aVL, V5, V6 left lateral
II, III, aVF inferior
aVR, V1 Right atrium
The Different Views Reflect The Angles At Which LEADS "LOOK" At
The Heart And The Direction Of The Heart's Electrical Depolarization.

36. A NORMAL ECG WAVE
REMEMBER

37. THE NORMAL SIZE <3 small square
< 2 large square
< 2 small square
<3-5 small square

38. DEPOLARIZATION
• Contraction of any muscle which is associated with
electrical changes called depolarization
• These changes can be detected by electrodes
attached to the surface of the body

39. If a wavefront of
depolarization
travels towards the
positive electrode, a
positive-going
deflection will result.
If the waveform
travels away from
the positive
electrode, a
negative going
deflection will be
seen.
Understanding
ECG Waveform

40. With EKGs we can identify:-
• Arrhythmias
• Myocardial ischemia and infarction
• Pericarditis
• Chamber hypertrophy
• Electrolyte disturbances (i.e. hyperkalemia,
hypokalemia)
• Drug toxicity (i.e. digoxin and drugs which
prolong the QT interval)

41. BLOOD FLOW THROUGH THE HEART

42. ELECTRICAL SYSTEM OF THE HEART

43. PACEMAKERS OF THE HEART
• SA Node - Dominant pacemaker with an intrinsic
rate of 60 - 100 beats/minute.
• AV Node - Back-up pacemaker with an intrinsic rate
of 40 - 60 beats/minute.
• Ventricular cells - Back-up pacemaker with an
intrinsic rate of 20 - 45 bpm.

44. IMPULSE CONDUCTION & THE ECG
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers

45. ECGINTERPRETATION
The More You See, The More You Know

46. OBTAIN A N ECG, ACT CONFIDENT, READ THE PT DETAILS

47. OBTAIN A N ECG, ACT CONFIDENT, READ THE PT DETAILS
Some ECG machines come with interpretation software. This one says
the patient is fine. DO NOT totally trust this software.

48. Rate
Rhythm
Cardiac Axis
P – wave
PR - interval
QRS Complex
ST Segment
QT interval (Include T and U wave)
Other ECG signs
THE BEST WAY TO INTERPRET AN ECG IS TO DO IT STEP-BY-
STEP

49. RATE

50. CALCULATING RATE
300
the number of BIG SQUARE between R-R interval
Rate =
As a general interpretation, look at lead II at the bottom part of the ECG strip.
This lead is the rhythm strip which shows the rhythm for the whole time the ECG
is recorded. Look at the number of square between one R-R interval. To calculate
rate, use any of the following formulas:
1500
the number of SMALL SQUARE between R-R interval
OR
Rate =

51. CALCULATING RATE
300
Rate =
For example:
3
150
015
Rate =or
Rate = 100 beats per minute

52. If you think that the rhythm is not regular, count the number of electrical beats in
a 6-second strip and multiply that number by 10.(Note that some ECG strips have 3
seconds and 6 seconds marks) Example below:
CALCULATING RATE
1 2 3 4 5 6 7 8
= (Number of waves in 6-second strips) x 10
= 8 x 10
= 80 bpm
Rate
There are 8 waves in this 6-seconds strip.

53. You can also count the number of beats on any one row over the ten-second strip
(the whole lenght) and multiply by 6. Example:
CALCULATING RATE
= (Number of waves in 10-second strips) x 6
= 13 x 6
= 78 bpm
Rate

54. Interpretation bpm Causes
Normal 60-99 -
Bradycardia <60 hypothermia, increased vagal tone (due to vagal
stimulation or e.g. drugs), atheletes (fit people)
hypothyroidism, beta blockade, marked intracranial
hypertension, obstructive jaundice, and even in
uraemia, structural SA node disease, or ischaemia.
Tachycardia >100 Any cause of adrenergic stimulation (including
pain); thyrotoxicosis; hypovolaemia; vagolytic drugs
(e.g. atropine) anaemia, pregnancy; vasodilator
drugs, including many hypotensive agents; FEVER,
myocarditis
CALCULATING RATE

55. RHYTHM

56. Look at p waves and their relationship to QRS complexes.
Lead II is commonly used
Regular or irregular?
If in doubt, use a paper strip to map out consecutive beats and see whether the
rate is the same further along the ECG.
Measure ventricular rhythm by measuring the R-R interval and atrial rhythm by
measuring P-P interval.
RHYTHM

57. RHYTHM
ECG rhythm characterized by a usual rate of anywhere between 60-99 bpm,
every P wave must be followed by a QRS and every QRS is preceded by P
wave. Normal duration of PR interval is 3-5 small squares. The P wave is
upright in leads I and II
Normal Sinus Rhythm

58. Sinus Bradycardia
RHYTHM
Rate < 60bpm, otherwise normal

59. RHYTHM
Sinus Tachycardia
Rate >100bpm, otherwise, normal

60. RHYTHM
Atrial Fibrillation
A-fib is the most common cardiac arrhythmia involving atria.
Rate= ~150bpm, irregularly irregular, baseline irregularity, no visible p waves,
QRS occur irregularly with its length usually < 0.12s

61. RHYTHM
Atrial Flutter
Atrial Rate=~300bpm, similar to A-fib, but have flutter waves, ECG baseline
adapts ‘saw-toothed’ appearance’. Occurs with atrioventricular block (fixed
degree), eg: 3 flutters to 1 QRS complex:

62. RHYTHM
Ventricular tachycardia
fast heart rhythm, that originates in one of the ventricles- potentially life-
threatening arrhythmia because it may lead to ventricular fibrillation, asystole,
and sudden death.
Rate=100-250bpm

63. RHYTHM
Ventricular
Fibrillation
A severely abnormal heart rhythm (arrhythmia) that can be life-threatening.
Emergency- requires Basic Life Support
Rate cannot be discerned, rhythm unorganized

64. RHYTHM
Torsades de Pointes ( polymorphic VT)
literally meaning twisting of points, is a distinctive form of polymorphic
ventricular tachycardia characterized by a gradual change in the
amplitude and twisting of the QRS complexes around the isoelectric
line. Rate cannot be determined.

65. RHYTHM
Supraventricular Tachycardia
SVT is any tachycardic rhythm originating above the ventricular tissue.Atrial and
ventricular rate= 150-250bpm
Regular rhythm, p is usually not discernable.
*Types:
•Sinoatrial node reentrant tachycardia (SANRT)
•Ectopic (unifocal) atrial tachycardia (EAT)
•Multifocal atrial tachycardia (MAT)
•A-fib or A flutter with rapid ventricular response. Without rapid ventricular response both
usually not classified as SVT
•AV nodal reentrant tachycardia (AVNRT)
•Permanent (or persistent) junctional reciprocating tachycardia (PJRT)
•AV reentrant tachycardia (AVRT)

66. RHYTHM
Asystole
a state of no cardiac electrical activity, hence no contractions of the
myocardium and no cardiac output or blood flow.
Rate, rhythm, p and QRS are absent

67. METHODS OF DEFIBRILLATION
The shock is generally conducted through the heart by
two electrodes, in the form of two hand-held paddles
or adhesive patches depending on the variety of the
defibrillator.

68. POSITION OF THE PADDLES
ADULT:-One paddle is placed in
the right infraclavicular region, while
the other is placed in the left 5th
- 6th
intercostal space anterior axillary
line.
PEDIATRIC:- Alternatively antero-
posterior may be used: one paddle is
placed in the left infrascapular region
while the other is placed in the left 5th
-
6th
intercoastal space anterior axillary
line.

69. METHODS OF DEFIBRILLATION
Open-chest defibrillators also exist, which have
electrodes in the form of two cup-shaped paddles
that surround the sides of the heart and shock it
directly.
Open-chest defibrillators generally require less energy
to operate due to direct contact with the heart .

70. METHODS OF DEFIBRILLATION
The number of attempts is in practice limited to a
series of three or four attempts at increasing
energies.
The likelihood of restoring normal heart rhythm is
much less in successive attempts.

73. AUTOMATED EXTERNAL
DEFIBRILLATOR (AED)
• AEDs come in various models.
• Some operator interaction
required.
• A specialized computer
recognizes heart rhythms that
require defibrillation.

75. Potential AED Problems
• Battery is dead.
• Patient is moving.
• Patient is responsive and has
a rapid pulse.

76. AED ADVANTAGES
• ALS providers do not need to be on
scene.
• Remote, adhesive defibrillator pads
are used.
• Efficient transmission of electricity

77. RATIONALE FOR EARLY
DEFIBRILLATION
• Early defibrillation is the third link in the chain of
survival.
• A patient in ventricular fibrillation needs to be
defibrillated within 2 minutes.

78. AED Maintenance
• Read operator’s manual.
• Check AED and battery at beginning of each shift.
• Get a checklist from the manufacturer.
• Report any failures to the manufacturer and the
FDA.

79. PREPARATION
• Make sure the electricity injures no one.
• Do not defibrillate a patient lying in pooled water.
• Dry a soaking wet patient’s chest first.
• Do not defibrillate a patient who is touching metal.
• Remove nitroglycerin patches.
• Shave a hairy patient’s chest if needed.

80. Using an AED (1 of 8)
• Assess responsiveness.
• Stop CPR if in progress.
• Check breathing and pulse.
• If patient is unresponsive
and not breathing
adequately, give two slow
ventilations.

81. Using an AED (2 of 8)
• If there is a delay in
obtaining an AED, have
your partner start or
resume CPR.
• If an AED is close at
hand, prepare the AED
pads.
• Turn on the machine.

82. Using an AED (3 of 8)
• Remove clothing from
the patient’s chest area.
Apply pads to the chest.
• Stop CPR.
• State aloud, “I Clear,
you clear everybody
clear”.

83. Using an AED (4 of 8)
• Push the analyze button, if
there is one.
• Wait for the computer.
• If shock is not needed,
start CPR.
• If shock is advised, make
sure that no one is
touching the patient.
• Push the shock button.

84. Using an AED (5 of 8)
• After the shock is delivered, begin 5 cycles of CPR,
beginning with chest compressions.
• After 5 cycles, reanalyze patient’s rhythm.
• If the machine advises a shock, clear the patient and
push shock button.
• If no shock advised, check for pulse.

85. Using an AED (6 of 8)
• If the patient has a
pulse, check breathing.
• If the patient is breathing
adequately, provide
oxygen via
nonrebreathing mask
and transport.

86. Using an AED (7 of 8)
• If the patient is not
breathing adequately, use
necessary airway adjuncts
and proper positioning to
open airway.
• Provide artificial
ventilations with high-
concentration oxygen.
• Transport.

87. Using an AED (8 of 8)
• If the patient has no pulse, perform 2 minutes of CPR.
• Gather additional information on the arrest event.
• After 2 minutes of CPR, make sure no one is touching the
patient.
• Push the analyze button again (as applicable).
• If necessary, repeat alternating CPR/Analyze/Shock until ALS
arrives.
• Transport and check with medical control.
• Continue to support the patient as needed.

88. After AED Shocks
• Check pulse.
• No pulse, no shock advised
• If a patient is breathing independently:
• Administer oxygen.
• Check pulse.
• If a patient has a pulse but breathing is
inadequate, assist ventilations.

89. TRANSPORT CONSIDERATIONS
• Transport:
• When patient regains pulse
• After delivering six to nine shocks
• After receiving three consecutive “no shock
advised” messages
• Keep AED attached.
• Check pulse frequently.
• Stop ambulance to use an AED.

90. CARDIOVERSION

91. DEFINITION
Cardio version is a synchronized administration of
shock during the R waves or QRS complex of a
cardiac cycle.
Cardioversion is a method to restore a rapid heart
beat back to normal .
Cardioversion is used in persons who have heart
rhythm problems (arrhythmias), which can cause
the heart to beat too fast.

92. CARDIO VERSION
Most elective or non-emergency Cardio versions are
performed :
• To treat atrial fibrillation or atrial flutter to regain heart
rhythm.
• To treat disturbances originating in the upper
Chambers (atria) of the heart.

93. CARDIO VERSION
Cardio version is used in emergency
situations to correct a rapid abnormal
rhythm associated with faintness,
low blood pressure, chest pain,
difficulty breathing, or loss of
consciousness.

94. INDICATIONS
• Supraventricular tachycardia (atrioventricular nodal
reentrant tachycardia [AVNRT] and atrioventricular
reentrant tachycardia [AVRT])
• Atrial fibrillation
• Atrial flutter (types I and II)
• Ventricular tachycardia with pulse.

95. TYPES OF CARDIO VERSION
Cardio version can be "CHEMICAL" or
"ELECTRICAL".
• CHEMICAL CARDIO VERSION: refers to the
use of antiarrhythmia medications
to restore the heart's normal rhythm.

96. TYPES OF CARDIO VERSION

100. POSITION OF THE PADDLES
ADULT:-One paddle is placed in
the right infraclavicular region, while
the other is placed in the left 5th
- 6th
intercostal space anterior axillary
line.
PEDIATRIC:- Alternatively antero-
posterior may be used: one paddle is
placed in the left infrascapular region
while the other is placed in the left 5th
-
6th
intercoastal space anterior axillary
line.

101. THE GOALS OF THE
ELECTRICAL CARDIO
VERSION
• Is to disrupt the abnormal electrical circuit(s) in the
heart.
• To restore a normal heart beat.

102. PHARMACOLOGIC CARDIO
VERSION
Cardioversion can be done using drugs that are taken
by mouth or given through an intravenous line (IV).
It can take several minutes to days for a
successful cardio version.
Ex:- Amiodarone therapy (Antiarrythmic agent) starting
4 weeks before and continuing for up to 12 months.

103. PHARMACOLOGIC CARDIO
VERSION
• If pharmacological cardioversion is done in
a hospital, your heart rate will be regularly
checked.
• Cardioversion using drugs can be done outside the
hospital, but this requires close follow-up with a
cardiologist.

104. PHARMACOLOGIC CARDIO
VERSION
Blood thining medicines may be given
with electrical cardioversion to prevent
clots from moving to the heart.

105. COMPLICATIONS
Possible complications of cardioversion
are uncommon but may include:
• Worsening of the arrhythmias .
• Blood clots that can cause a stroke or other organ
damage, bruising, burning or pain where the paddles
were used.
• Allergic reactions from medicines used in
pharmacologic cardioversion .

106. EQUIPMENT
• Defibrillator with a synchronizing button.
• Emergency trolley with emergency drugs;
( lignocaine, atropine, and adrenaline ).
• Oxygen mask, intubation equipment, airway .
• Monitor and continuous recording facilities.

107. PREPARING FOR A CARDIO
VERSION
 Do not eat or drink for at least eight hours prior to the
procedure.
 Take your regularly scheduled medications the morning
of the procedure unless your medical practitioner has told
you otherwise .
 Bring a list of all your medications with you.

108. PREPARING FOR A CARDIO
VERSION
 Do not apply any lotions or ointments to chest or back as
this may interfere with the adhesiveness of the shocking
pads.
 Do not drive yourself home after receiving sedation
anesthesia.

109. PREPARING FOR A CARDIO
VERSION
 Do not operate a car, heavy machinery, or make any
important decisions.
 Stop digoxin before 48 hours prior the procedure.
 Apply ointment to the area to reduce the discomfort.

110. OUTCOME
The procedure will be terminated either by
a successful reversion to sinus rhythm or
when the medical officer determines that
cardio version will not revert the rhythm.

111. • It is a non- synchronized
delivery of energy during any
phase of the cardiac cycle.
• Indications: VT/VF
• Usually an emergency
treatment.
• May or may not always use
sedation, sometimes mild
administration of sedation is
done.
• Delivery of energy that is
synchronized to the large R
waves or QRS complex.
• Indications: SVT, AF, sinus
tachycardia, Ventricular
tachycardia.
• Cardio version is usually a
planned procedure.
• always use sedation,
administration of sedation is
done with short acting agents
such as MIDAZOLAM.

112. SPECIAL POPULATION
Cardio version in patients with digitalis
toxicity
• Digoxin overdose or toxicity can present with any
type of tachyarrhythmias or bradyarrhythmias.
Cardioversion in the setting of digoxin toxicity is a
relative contraindication. Digitalis sensitizes the
heart to the electrical stimulus. Prior to
cardioversion, electrolytes should be normalized.
Cardioversion may cause additional arrhythmias,
especially ventricular fibrillation.

113. SPECIAL POPULATION
Cardioversion in patients with permanent
pacemakers/ICDs
• Cardioversion in patients with permanent
pacemaker/ICD should be performed with extra care.
Improper technique may damage the device, lead
system, or myocardial tissue, resulting in device
malfunction. The electrode paddle or patch should be at
least 12 cm from the pulse generator and
anteroposterior paddle position.[15, 16]
The lowest amount of
energy should be used during cardioversion, based on
the patient’s clinical condition. After cardioversion, the
pacemaker/ICD should be interrogated to ensure normal
function of the device.

114. SPECIAL POPULATION
Cardioversion during pregnancy
• Cardioversion can be performed safely in pregnant
women. The fetal heart rate should be monitored
during the procedure using fetal monitoring
techniques.