heart block, types, Nursing management, diagnosis

1. HEART BLOCK/
AV BLOCK

2. Normal conduction pathway:
SA node -> atrial muscle -> AV node -> bundle of His ->
Left and Right Bundle Branches -> Ventricular muscle

6. DEFINITION
Heart block is an abnormal heart rhythm
where the heart beats too slowly
(bradycardia).
In this condition, the electrical signals that tell the
heart to contract are partially or totally blocked
between the upper chambers (atria) and the lower
chambers (ventricles).

7. ATRIOVENTRICULAR (AV)
BLOCK
1. First degree AV block
2. Second degree AV block
i. Mobitz type I or Wenkebach AV block
ii. Mobitz types II AV block
3. Third degree AV block

10. PATHOPHYSIOLOGY
No arterial impulse conducted
through the AV node into the
ventricles
Independent atrial and ventricular
complexes, No/less connection of
conduction
Atrial rate greater than
ventricular rate

11. FIRST DEGREE HEART
BLOCK
• First-degree atrio-ventricular block (AV block),
or PR prolongation, is a disease of the
electrical conduction system of the heart in
which the PR interval is lengthened beyond
0.20 seconds.

13. The following are the most common causes of first-
degree AV block:
• Acute myocardial infarction (MI),
particularly acute inferior wall MI
• Myocarditis
• Electrolyte disturbances (eg,
hypokalemia, hypomagnesemia)
• Drugs (especially those drugs that increase the
refractory time of the AVN, thereby slowing
conduction)

14. First Degree Heart Block(1º)
• SA Node – normal
• Normal P wave
• AV Node conducts more slowly
than normal
• Prolonged PR
Interval
• Rest of conduction is normal
• Normal QRS

15. Significance
• Clinical significance
• None
• Treatment
• None
• Note – this can progress to 2º or 3º heart
block

16. Second Degree Heart Block
(2º)
• Mobitz Type I
(Wenkebach)
• Mobitz Type II

17. Second Degree Heart Block(2º)
Mobitz TypeI
(Wenckebach)
• Conduction through the AV Node – progressively delayed
until
a drop beat is seen

18. Second-degree atrio-ventricular (AV) block,
or second-degree heart block, is
characterized by disturbance, delay, or
interruption of atrial impulse conduction
through the AV node to the ventricles.

19. CAUSES
• Drugs (beta-blockers, calcium channel blockers,
– amiodarone)
• Cardiomyopathy
• rheumatic fever, myocarditis
• varicella-zoster virus infection
• Rheumatic diseases
• Hypoxia
• Hyperkalemia
• Hypothyroidism
• inferior wall myocardial infarction

20. Second Degree Heart Block(2º)
Mobitz TypeI
(Wenkebach)
• PR Interval prolongs with each beat until a dropped
beat
is seen
• The PR Interval is NOT constant
• After each dropped beat, the PR interval is normal
and
the cycle starts again

21. Second Degree Heart Block(2º)
Mobitz TypeI
(Wenkebach)
P
R
P
R
P
R
DROPPED
BEAT

22. Significance
• Clinical Significance
• Slight symptoms e.g..
Lethargy, Confusion
• Treatment
• Pacemaker if during day
&/or symptoms
• No treatment if at night
• Note – this can progress to 3º Heart Block

23. Second Degree Heart
Block(2º) Mobitz TypeII
• Conduction through the AV node is
constant.
• PR interval is normal and constant
• Occasionally a dropped beat is seen

24. Second Degree Heart
Block(2º) Mobitz TypeII
P
R
P
R
DROPPED BEAT
P
R

25. Significance
• Clinical significance – this is more significant
disease
• Treatment – pacemaker
• Note – this can progress to 3º Heart Block

26. Third Degree Heart
Block(3º) (Complete)
• Complete failure of the AV Node
• No impulses from Sinus Node will pass through to
the ventricles
• Some part if the conducting system will take over
as pacemaker of the heart (even a myocardial cell
10-15 bpm)

27. Third-degree atrioventricular (AV) block, also
referred to as third-degree heart block or
complete heart block, is a disorder of the cardiac
conduction system where there is no conduction
through the atrioventricular node.

28. Third Degree Heart Block
(3º) (Complete)
• P wave rate – normal
• Ventricular rate – slow
• Ventricular complex may be broad
• Idioventricular rhythm
• Complete dissociation between P waves &
QRS

29. Third Degree Heart Block (3º)
(Complete)
P P P P P
QR
S
QR
S

30. Significance
• clinical significance
• Symptoms LOC,
Confusion, Dizziness,
Low BP
• Can lead to standstill, VT or
VF (stokes Adams)
• Treatment - pacemaker

32. CLINICAL MANIFESTATIONS
Reduced CO with
subsequent ischemia
Heart failure
Shock
Syncope
Severe bradycardia or
even periods of asystole.

33. DIAGNOSTIC EVALUATION
1. ECG (electrocardiogram)
2. Holter monitoring
3. Echocardiogram
4. Electrophysiology test

34. MANAGEMENT
1. A transcutaneous pacemaker is used
until a temporary transvenous
pacemaker can be inserted.
2. The use of drugs such as atropine,
epinephrine, isoproterenol, and
dopamine is a temporary measure to
increase measure HR and Support
blood pressure (BP) until temporary
pacing is initiated.
3. Patients will need a permanent
pacemaker as soon as possible.

36. COMPLICATION
1. Arrhythmia (irregular heart beat)
2. Bradycardia (low heart rate)
3. Cardiac arrest

38. NURSING MANAGEMENT
1. Assess the high risk patients
2. Monitor ECG of the patient
3. Assess the family history of heart
disease
4. Assess the history of smoking and
alcoholism
5. Monitor lab values frequently
especially serum cholesterol
levels.
6. Assess for CAD
7. Monitor vital signs
8. Instruct to avoid high fat and oil
rich diet

39. Nursing
Diagnosis
Goals Implementation Expected
outcome
Impaired
physical
mobility
related to
activity
restriction
To prevent
complicati
ons of
immobilit
y
o Assess patient’s general
condition.
o Implement therapies to prevent
complications of immobility.
o Instruct on range of motion
exercise, isometric exercises of
the lower extremities, deep
breathing exercises, and
shifting weight from side to
side.
o Apply antiembolism stockings
and pressure-relieving pads
and appliances to bed.
o Assist patient with
repositioning and daily care
activity
Patient will
participate
i
n therapies.
NURSING MANAGEMENT

40. Nursing
Diagnosis
Goals Implementation Expected
outcome
Anxiety
related to
cardiac
disorder and
the impending
temporary
pacemaker
insertion
as evidenced
by
verbalisation
To
reliev
e anxiety
o Assess patient’s anxiety level.
o Teach about the dysrhythmia and
its cause and treatment, the
temporary pacemaker insertion
procedure, the local anesthesia
and analgesia used, places the
patient will go after the procedure,
ways the patient will feel the
temporary lead in place, and
restriction of the affected
extremity.
o Assess patient’s ability and
willingness to participate in
relaxation sessions before and
during the pacemaker insertion.
o Use guided imagery to ‘walk’ patient
through the procedure.
o Assess patient’s level of anxiety
after session.
o Take feedback from the patient.
Patient will
verbalize
a
n
understanding
of the disease
and
management.
Patient will
participate
i
n relaxation
sessions.

41. Nursing
Diagnosis
Goals Implementation Expected
outcome
High risk for
fluid volume
deficit
related to
bleeding due
to the
transvenous,
epicardial, or
transthoracic
lead
insertion
To
maintai
n
fluid
balance
o Monitor insertion site for
signs and symptoms of
hematoma
formation or decreased arterial
perfusion.
o Apply manual pressure to
insertion site
o Assess arterial pulses distal to
insertion site
o Monitor for signs and
symptoms of intrapericardial
bleeding, including decreasing
blood pressure, rising venous
pressure, pulus paradoxus, and
distal heart sounds.
o Monitor for signs and
symptoms of hemothorax,
including a fall in blood
pressure, diaphoresis, or pallor,
Patient
will
not develop
bleeding/hem
atoma
o
r
hemothroax

42. Nursing
Diagnosis
Goals Implementation Expected
outcome
High risk for
decrease
cardiac
output
related to
bradydysrhy
thmias and a
delay in the
insertion of
the
temporary
pacing
system
To prevent
signs
an
d
symptoms
of
decreased
cardiac
output,
and
maintain
hemodyn
a
mical
stabilit
y
o Monitor for signs and
symptoms of decreases cardiac
output
such as systolic blood pressure
less than 90 mm Hg, change in
level of consciousness,
abnormal arterial blood gas
levels, and urinary output less
than 30 ml/hr
o Initiate therapy to maintain or
achieves hemodynamic
stability.
o For
bradydysrhythmias
administer atropine and
isoproterenol and assess for
ventricular irritability.
o For tachydysrhythmia
administer digitalis, perfrom
synchronized cardioversion,
Patient
wil
l be
hemodynami
cally stable.

43. Nursing
Diagnosis
Goals Implementation Expected
outcome
High risk for
infection
related to
precutaneou
s placement
To prevent
infection
o Assess patient’s vital signs and
record.
o Initiate appropriate infection
control measures and monitor
for signs and symptoms of
infection.
o Apply antibacterial ointment and
sterile dressing to insertion site.
o Change sterile dressing daily
o Assess for pain, redness,
swelling, or purulent drainage.
o Culture drainage tip of lead on
removal.
Patient
will
not develop
infection

44. Nursing
Diagnosis
Goals Implementation Expected
outcome
High risk for
microshock
related to the
presence of
the
temporary
pacing lead
To prevent
atrial
o
r
ventricular
tachydysr
h ythmia
o Prevent microshock by
maintaining electrical safety
o Insulate all exposed parts of
the lead
o Wear rubber gloves when
handling pacemaker terminals
or the lead and when changing
batteries
o Use nonelectric beds
o Avoid applying 2 different line-
powered electrical devices to
the patient at one time
o Disconnect pacemaker from the
lead during defibrillation
o Instruct patient to avoid
contact with all other
electrical equipment
Patient
will
not develop
atrial or
ventricular
tachydysrh
yt hmia.

45. THANK YOU