Heart block

1. Mrs. D. Melba Sahaya Sweety
M.Sc Nursing
GIMSAR

2. INTRODUCTION
• Electrical signals control the beating of your heart.
They tell your heart muscle when to contract, a
process known as conduction. The normal timing
of heartbeats is generated in the upper chamber
of the heart (atria) in a structure called the sinus
node. The signal moves from the sinus node
through the atria, causing contraction in the
upper chambers. It then passes to the lower
chambers (ventricles) of the heart, causing a
contraction in the ventricles. When you have heart
block, there is interference with the electrical
signals that usually travel from the atria to the
ventricles. This is known as a conduction disorder.
If the electrical signals can’t move from your atria
to your ventricles, they can’t tell your ventricles to
contract and pump blood correctly.

3. DEFINITION
• Heart block is an
abnormal heart rhythm
where the heart beats
too slowly, which results
in the electrical signals
being partially or totally
blocked between
the upper chambers
(atria) and lower
chambers (ventricles).
Heart block is also
called atrioventricular
(AV) block.

4. INCIDENCE
•Prevalence of chronic AV block
is 2.47% per year In India with
West Bengal tops the list with
almost more than 70%
prevalence, Assam with 10%,
Bihar with 12.8%, Orissa 5% and
Tripura with 2% prevalence.

5. RISK FACTORS
Older age Risk of heart block increases with
age.
Congenital Heart diseases
Rheumatic heart disease or sarcoidosis.
An overactive vagus nerve (causes the
heart to slow down).
 Medications that slow the conduction of
the heart’s electrical impulses including some
heart medications (beta blockers, calcium
channel blockers, digoxin), high blood
pressure drugs, anti-arrhythmics; muscle
relaxants and sedatives; antidepressants and
antipsychotics; diuretics; lithium.

6. RISK FACTORS
Low potassium level and low
magnesium level.
Hyperthyroidism, or overactive
thyroid
Lyme disease
Recent open-heart surgery
An autoimmune disease Diseases,
such as lupus, can be passed by your
mother in certain proteins through
the umbilical cord.
Advanced kidney disease

7. ETIOLOGY
• The most common cause of heart block is
heart attack.
• Other causes include heart muscle
disease, usually called a cardiomyopathy,
heart valve diseases and problems with
the heart’s structure.
• High potassium levels,
• Heart block can also be caused by
damage to the heart during open heart
surgery, as a side effect of some
medications or exposure to toxins.
• Genetics can be another cause.

8. TYPES OF HEART BLOCK
Types of Heart
Block
Sinoatrial
nodal
blocks
SA node
Wenckebach
(Mobitz I)
SA
node
Mobitz
II
SA
node
exit
block
Infra-Hisian
blocks
Atrioventricular
block
First
degree
AV
block
Second
degree
AV
block
Third
Degree
AV
block

9. SINOATRIAL NODAL BLOCK
• A sinoatrial block (also spelled sinuatrial
block) is a disorder in the normal rhythm of
the heart, known as a heart block, that is
initiated in the sinoatrial node. The
initial action impulse in a heart is usually
formed in the sinoatrial node (SA node) and
carried through the atria, down
the internodal atrial pathways to
the atrioventricular node (AV) node. In
normal conduction, the impulse would travel
across the bundle of His (AV bundle), down
the bundle branches, and into the Purkinje
fibers. This would depolarize the ventricles
and cause them to contract.

10. SINOATRIAL NODAL BLOCK
• In an SA block, the electrical impulse is
delayed or blocked on the way to the
atria, thus delaying the atrial beat.
• SA blocks rarely give severe symptoms,
because even if an individual had
complete block at this level of the
conduction system (which is uncommon),
the secondary pacemaker of the heart
would be at the AV node, which would fire
at 40 to 60 beats a minute, which is
enough to retain consciousness in the
resting state.

11. SINOATRIAL NODAL BLOCK TYPES
•SA node Wenckebach (Mobitz I): In This type there
is a delay in the conduction from the sinoatrial node to the
atrium and this delay increases gradually untill one impulse is
completely blocked and a loss of P wave occurs.The P-P or R-R
interval is gradually decreased while the P-R interval remains
constant, until a QRS segment is dropped. The p-cells in the
centre of the node produce the rhythm at a regular rate, but
their conduction across the node to where it meets atrial tissue
is where the slowing occurs.

12. SINOATRIAL NODAL BLOCK TYPES
•SA node (Mobitz II):
• In this type there is no impulses are
conducted from the sinoatrial node to the
atrium. Implies dropped P wave without
any preceding change in the R-R or P-P
interval. The subsequent “sinus pause”
is an exact interval of the preceding R-R
intervals (usually two times).

13. SINOATRIAL NODAL BLOCK TYPES
•SA node Exit Block:
It refers to complete failure of the sinoatrial node to
conduct impulses to the atrial tissue and is reflected by
the absence of P waves on surface ECG. Third-degree
sinoatrial exit block is clinically identical to sinus
arrest. When a junctional escape ensues, the rhythm
may be confused with a junctional rhythm. If no
junctional escape rhythm is present, a long pause
resulting in asystole and cardiac arrest can occur.

14. ATRIOVENTRICULAR BLOCK
• Atrioventricular
block (AV block) is
characterized by an
interrupted or
delayed conduction
between
the atria and the
ventricles. There
are three degrees
of AV block,
categorized
according to the
extent of the delay
or interruption.

15. ATRIOVENTRICULAR BLOCK TYPES
•First-degree atrioventricular block
(AV block) It occurs when there is a
delay, but not disruption, as the
electrical signal moves between the
atrium and the ventricles through the AV
node. The PR interval is lengthened
beyond 0.20 seconds.

16. ATRIOVENTRICULAR BLOCK TYPES
•Second -degree atrioventricular
block (AV block) It occurs when the
electrical signal between the atria and ventricles
is even more impaired than in a first-degree AV
block. In a second-degree AV block, the
impairment results in a failure to conduct an
impulse, which causes a skipped beat. It is
Further Divided in to two types
• Type I, also called Mobitz Type I or
Wenckebach’s AV block
• Type II, also called Mobitz Type II

17. ATRIOVENTRICULAR BLOCK TYPES
•Wenckebach’s AV block :This is a
less serious form of second-degree heart
block. The electrical signal gets slower and
slower until the heart actually skips a beat. the
PR interval gets longer and longer until a beat
is finally dropped, or skipped)

18. ATRIOVENTRICULAR BLOCK TYPES
•Type II, also called Mobitz Type II
While most of the electrical signals reach the
ventricles every so often, some do not and the
heartbeat becomes irregular and slower than
normal. is caused by a sudden, unexpected failure of
the His-Purkinje cells to conduct the electrical
impulse. On ECG, the PR interval is unchanged from
beat to beat, but there is a sudden failure to conduct
the signal to the ventricles, and a resulting random
skipped beat

19. ATRIOVENTRICULAR BLOCK TYPES
•Third -degree atrioventricular block
(AV block): The electrical signal from the
atria to the ventricles is completely blocked.
and there is no communication between the
two, To make up for this, the ventricle usually
starts to beat on its own acting as a substitute
pacemaker but the heartbeat is slower and
often irregular and not reliable. Third-degree
block seriously affects the heart’s ability to
pump blood out to your body. On ECG, there is
no relationship between P waves and QRS
complexes, meaning the P waves and QRS
complexes are not in a 1:1 ratio.

20. ATRIOVENTRICULAR BLOCK TYPES

21. INFRA-HISIAN BLOCKS
• Infra-Hisian block is defined as an
impaired conduction in the electrical
system of the heart that occurs below
the atrio Types of infra-Hisian block
include:
• Type 2 second degree heart block
(Mobitz II) –a type of AV block due to a
block within or below the bundle of His
• Left anterior fascicular block
• Left posterior fascicular block
• Right bundle branch block

22. INFRA-HISIAN BLOCKS
•Left anterior fascicular block:
Left anterior fascicular block (LAFB) is an
abnormal condition of the left ventricle of the
heart It is caused by only the anterior half of
the left bundle branch being defective. It is
manifested on the ECG by left axis deviation.
It is much more common than left posterior
fascicular block.

23. INFRA-HISIAN BLOCKS
• Left Posterior fascicular block: A left posterior
fascicular block (LPFB), also known as left posterior
hemiblock (LPH), is a condition where the left posterior
fascicle, which travels to the inferior and posterior portion
of the left ventricle,does not conduct the electrical impulses
from the atrioventricular node. The wave-front instead
moves more quickly through the left anterior fascicle and
right bundle branch, leading to a right axis deviation seen
on the ECG.

24. INFRA-HISIAN BLOCKS
•Right bundle branch block Right bundle branch
block (RBBB) is a blockage of electrical impulses to the heart’s right
ventricle. This is the lower-right part of the heart. During a right
bundle branch block, the right ventricle is not directly activated by
impulses travelling through the right bundle branch. The left ventricle,
however, is still normally activated by the left bundle branch. These
impulses are then able to travel through the myocardium of the left
ventricle to the right ventricle and depolarize the right ventricle this
way. As conduction through the myocardium is slower than
conduction through the Bundle of Bundle of His-Purkinje fibres,
the QRS complex is seen to be widened

25. PATHOPHYSIOLOGY OF AV BLOCK
Due to Etiological Factors
The Av node signals is not reaching to the
Ventricles
Back up pacemakers in the ventricles begin to
compensate
Decreased pacing in ventricular pumping
Decreased ventricular work
Decreased Blood supply to the Systemic Circulation and
decreased perfusion to other vital organs

26. CLINICAL MANIFESTATION
First-degree heart block: May not
have any symptoms.
Second-degree heart block
symptoms:
• Fainting, feeling dizzy.
• Chest pain.
• Feeling tired.
• Shortness of breath.
• Heart palpitations.
• Rapid breathing.
• Nausea.

27. CLINICAL MANIFESTATION
Third-degree
heart block
symptoms:
•Dizziness,
fainting.
•Chest pain.
•Feeling tired.
•Shortness of
breath.
Sinoatrial block
symptoms
Lightheadedness,
Fatigue,
Palpitations,
Dyspnea on
exertion,
Chest discomfort
Presyncope, and
syncope.

28. DIAGNOSTIC EVALUATION
• History Collection : Any family history of
heart block or previous history of heart
disease, Medication intake, Lifestyle
choices, such as smoking or using drugs
and alcholism.
• Physical Examination : Auscultate the
heart rate for Bradycardia
• An electrocardiogram (ECG) records of
the heart’s electrical activity – its heart rate
and rhythm and the timing of electrical
signals as they move through your heart.
This test can help determine the severity of
the heart block

29. • An implantable loop recorder: This is a
very slender device that is injected under
the skin of your chest and can monitor your
heart rhythm for up to five years. This is
implanted as an outpatient in just a few
minutes and is useful for patients who have
very infrequent but important episodes
without a clear explanation of their origin.
• An electrophysiology study involves
inserting a long, thin tube called a catheter
through a blood vessel and guiding it to
heart to measure and record electrical
activity from inside heart.
DIAGNOSTIC EVALUATION

30. MANAGEMENT
• First-degree block: If you have first-
degree heart block, you probably won’t
need treatment.
• Second-degree block: If you have second-
degree heart block and have symptoms, you
may need a pacemaker to keep your heart
beating like it should. A pacemaker is small
device that sends electrical pulses impulses
to your heart.
• Discontinue or reduce medications causing
AV block or follow detoxification strategies
in case of: Beta blocker toxicity, Digoxin
toxicity

31. • Third-degree block: Third degree
heart block is often first discovered
during an emergency situation.
Treatment almost always includes a
pacemaker.
• 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.
MANAGEMENT

32. •Cardiac pacemaker Implantation
It is a medical device that generates electrical
impulses delivered by electrodes to cause the
heart muscle chambers to contract and
therefore pump blood; by doing so this device
replaces and/or regulates the function of the
electrical conduction system of the heart
SURGICAL MANAGEMENT

33. COMPLICATION
The complications can be life
threatening and include:
•Heart failure
•Arrhythmia (irregular
heartbeat)
•Heart attack
•Sudden cardiac arrest

34. LIFE STYLE MODIFICATION
•Eating a heart healthy diet
•Exercising regularly
•Getting an adequate amount of
sleep each night
•Reducing stress
• Limiting alcohol and stopping
smoking and use of illicit drugs.

35. LIFE AFTER PACEMAKER
IMPLANTATION
•Just like the heart, the pacemaker needs to be
treatedright to work well. There are some things
can do to get the most out of it:
•Know what kindof pacemaker you have.
•Let all the health care providers know about
your pacemaker.
•Wear a medical bracelet or necklace, to inform
others of your pacemaker in an emergency.
• Avoidlifting operative side arm above shoulder
level until approvedby care provider.

36. LIFE AFTER PACEMAKER
IMPLANTATION
Stay away fromelectrical devices with strong
magneticfields.
It’s fine to be active once you have your doctor’s OK,
but skip contact sports like football or ice hockey.
Get your pacemaker checkedregularly to make
sure it’s working well.
Microwave oven are safe to use and do not threaten
pacemaker function.
The patient should knowhow to take the pulse .

37. NURSING MANAGEMENT
• NURSES RESPONSIBILITY ON PACE
MAKER THERAPY
• Pre- Operative Care:-
•Check vital signs of the patient
•Monitor the ECG
•Explain the procedure ,type and technique of
pacemaker to the patient
•Explain Cost of the procedure and Hospital stay.
•Provide Psychological support and Reassure the
patient
• Explain the Process of the pacemaker insertion.
•Obtain written consent from the patient and from
nearest relative

38. NURSING MANAGEMENT
• NURSES RESPONSIBILITY ON PACE
MAKER THERAPY
•Intra-operative care
• Check serology: HIV, HbsAg, HCV and others
• Start an IV line with 5% Dextrose solution or
normal saline solution.
• Check the battery in pulse generator
• Prepare the emergency cart, the defibrillator
and jelly , and the ECG monitor
• Set up all equipment for the insertion of the
pacemaker

39. NURSING MANAGEMENT
• NURSES RESPONSIBILITY ON PACE
MAKER THERAPY
•Intra-operative care
• The nurse should know about the
pacemaker generator including the power
switch, indicator light for pacing and
sensing, stimulus output dial, sensitivity dial,
and their proper settings.
• Assist the doctor and the scrub nurse during
the procedure step by step
• Observe vital signs and observe ECG
monitor carefully for arrhythmias and other
complications.

40. NURSING MANAGEMENT
• NURSES RESPONSIBILITY ON PACE MAKER
THERAPY
• Post-operative care
 Receive the patient
 Keep the patient in comfort position
 Record the pacing parameters like Receiving time,
patient’s heart rate ,Other routine care
 Immobilize the affected part and keep in supine
position but allow the movement of finger and ankle
joint.
 Monitor heart rate and rhythm.
Monitor vitals signs and level of consciousness of
patient.
 Prevent infection.

41. NURSING MANAGEMENT
• NURSES RESPONSIBILITY ON PACE MAKER
THERAPY
•Post-operative care
 Take ECG and X-ray chest..
 Watch for complications
 Maintain follow up care with a physician to check
the pacemaker site and begin regular pacemaker
function checks .
Watch for signs of infection at incision site redness,
swelling dressing.
Watch for signs of infection at incision site redness,
swelling dressing.
Keep incision dry for 1 week after implantation.
 Avoid lifting operative side arm above shoulder level
until approved by care provider.

42. NURSING DIAGNOSIS
• Decrease cardiac output related to failure of the heart to
pump enough blood to meet metabolic needs of the body as
manifested by hypotension .
• Acute chest Pain related to decrease blood flow to
myocardium through coronary arteries as manifested by
discomfort and vocalization .
• Ineffective Tissue perfusion related to decrease cardiac
output as manifested by syncope .
• Fatigue related to increase hypoxic tissue and slowed
removal of metabolic wastes as evidenced by drowsiness and
less activity .

43. NURSING DIAGNOSIS
• Impaired Skin Integrity relatedto Insertion of
pacemaker and Loss of elasticity of the skin as
evidencedby Disruption of skin tissue
• Risk for Injury relatedto perforation of heart tissues
,Lead migration as evidenced by Decreased cardiac
output, Chest pain
• Risk for Infection relatedto Invasive procedure like
Pacemaker insertion as evidenced by Redness at site
of insertion, Pain and swelling