Dysrhythmia, Easy note for nursing students

1. Dysrhythmia
Prepared by
Ms Pooja Prakash
Cardio-vascular and
thoracic nursing

2. • A normal sinus rhythm is the usual heart
rhythm that begins in the sinoatrial (SA) node,
is between 60 and 100 beats/min, and has
normal intervals and no aberrant or ectopic
beats.
• Dysrhythmias are disorders of the heart
rhythm.
• is the disturbance in the electric cycle of the
heart.
• is a disorder of the formation or conduction (or
both) of the electrical impulses within the
heart.

3. • Sites of origin of Dysrythmias
- Sinoatrial Node
- Atria
- Atrioventricular Node
- Ventricles

4. • Common causes of Dysrhythmia
# Cardiac condition
- Cardiomypathy
- Conduction defects
- Myocardial cell degeneration
- Accessory pathways
- Myocardial infraction
- Heart failure Valve disease
# Other conditions
- Acid-base imbalance
- Alcohol
- Caffeine, tobacco
- Connective tissue disorder
- Drug effects (antidysrhythmic drugs, stimulants, beta-
adrenergic blockers)
- Electric shock
- Electro imbalances
- Emotional crisis

5. • Mechanism of conduction
- Normal
- Bradycardia
- Tachycardia
- Flutter
- Fibrillation
- Premature complexes
- blocks

6. PATHOPHYSIOLOGY
• The significance of all dysrhythmias is their
effect on cardiac output and therefore
cerebral and vascular perfusion.
• CO=SV*HR
• Co: Cardiac output
• SV: Stroke volume
• HR: Heart rate

7. DYSRHYTHMIA
1. Rhythms originating in
sinoatrial (SA) node
- Sinus bradycardia
- Sinus tachycardia
- Sinus arrest
2. Rhythms originating in atria
- Premature atrial contraction
- Atrial tachycardia
- Paroxysmal supraventricular
tachycardia
- Supraventricular tachycardia
3. Rhythms originating in
atrioventricular junction
- Premature jugular complex
- Junctional rhythm
- Junctional tachycardia
4. Rhythms originating in
ventricles
- Premature ventricular
contraction
- Ventricular tachycardia
- Ventricular fibrillation
5. Conduction abnormalities
- First degree atrioventricular
block
- Second degree
atrioventricular block
= Mobitz I
= Mobitz II
- Third degree atrioventricular
block

8. • Conduction pathway is same as
sinus rhythm but SA node fires at a
rate less than 60 beats/min.
• ECG characteristics:
- Rate : <60B/min
- Rhythm: regular
- P wave: precede every QRS
complex, consistent in shape
- PR interval: Normal (0.12- 0.20 sec)
- QRS complex: Normal (0.04 – 0.010
sec)
- Conduction: Normal through atria,
AV node, bundle branches,
ventricles
• Treatment:
- Anticholinergic drugs, atropin
- Pacemaker therapy may be
required

9. • Conduction pathway is same as
sinus rhythm but SA node fires at
a rate more than 100 beats/min.
• ECG characteristics:
- Rate : >100B/min
- Rhythm: regular
- P wave: precede every QRS
complex, consistent in shape
- PR interval: Normal (0.12- 0.20
sec)
- QRS complex: Normal (0.04 –
0.010 sec)
- Conduction: Normal through
atria, AV node, bundle branches,
ventricles
• Treatment:
- Treatment of hypovolemia
- Adenosine and beta-
adrenergic blockers

10. • Decreased Sinus node automaticity
• Impulses are not generated
• Absence of p wave, QRS complex
and no electrical activity for 3 sec
• ECG characteristics:
- Rate : Atrial normal or bradycardia,
ventricular normal or bradicardia
- Rhythm: Irregular due to absence of
sinus node discharge
- P wave: present when sinus node is
firing and absent during periods of
sinus arrest
- PR interval: Usually normal when p
waves are present
- QRS complex: usually Normal but
absent during sinus arrest
- Conduction: at the time of sinus
arrest there is no conduction
• Treatment:
- Atropin 0.5 to 1 mg IV may increase
the rate
- Pacemaker therapy may be required

11. Premature Atrial Contraction
• Contraction originating from an
ectopic focus in the atrium, other
than SA node.
• Ectopic signal may originates in the
left or right atrium and travels across
the atria by an abnormal pathway
creating a distorted p wave.
• ECG characteristics:
- Rate : Normal
- Rhythm: usually regular, PAC results
in early beat
- P wave: distorted P wave
- PR interval: normal or prolonged on
premature beat
- QRS complex: may be normal, wide,
absent depends on prematurity of
beat
- Conduction: normal
- Treatment:
- Beta-adrenergic blockers to decrease
prematurity of beat.

12. Atrial tachycardia

13. • Atrial tachycardia
- Rapid firing of an ectopic atrial focus or
to an atrial re-entery circuit allows an
impulse to travel rapidly and
repeatedly around pathway in the
atria.
• ECG characteristics:
- Rate : 120 to 125 b/m
- Rhythm: regular unless there is
variable block at AV node
- P wave: differ in configuration from
sinus P waves because they are
ectopic. Precede each QRS complex,
but may be hidden in preceding T-
wave. When block is present, more
than P wave appears before each QRS
complex.
- PR interval: may be shorter or
prolonged but often difficult to
measures because of hidden P-
waves.
- QRS complex: usually normal, but
may be wide if aberrant conduction is
present.
- Conduction: usually normal through
the AV node and into ventricles
- Treatment:
- Sedation
- Cardioversion
- Beta-blockers, verapamil and
diltiazem
- Digitalis
- Antiarrhythmic drugs
- Radiofrequency catheter ablation of
the ectopic focus

14. Paroximal Supraventricular Tachycardia
• Originating in an ectopic focus
anywhere above the bifurcation
of the bundle of his.
• Paroxysmal refers to an abrupt
onset and termination
• ECG characteristics:
- Rate : 100 to 300 b/min
- Rhythm: regular or slightly
irregular
- P wave: often hidden in the
preceding T wave, but if seen
may be abnormal in shape
- PR interval: may be shorter or
normal
- QRS complex: usually normal
- Treatment:
- IV adenosine
- IV beta adrenergic blockers
- Calcium channel blockers
- Amiodarone
- Digitalis
- Catheter ablation therapy

15. Supraventicular Tachycardia
• Originating in an ectopic focus
above the bundle of his
• ECG characteristics:
- Rate : 100 – 300 b/min
- Rhythm: regular
- P wave: usually not visible, burried
in T-wave
- PR interval: not measurable
- QRS complex: usually narrow, may
be wide
- Conduction: through atria varies
depending on the mechanism of
tachycardia. Atria may depolarize
in a retrograde direction in AV
nodal re-entry tachycardia.
Through ventricle is normal.
- Treatment:
- IV adenosine
- IV beta adrenergic blockers
- Calcium channel blockers
- Amiodarone
- Digitalis
- Catheter ablation therapy

16. Atrial Flutter

17. • Originates from single
ectopic focus in the right
atrium, identified by
recurring regular sawtooth-
shaped flutter (F-Waves)
• ECG characteristics:
- Rate : Atrial rate varies 250-
350 b/min; ventricular rate
is in normal range
- Rhythm: Atrial rhythm is
regular. Ventricular rhythm
may be regular or irregular
- P wave: replaced by F-
waves
- PR interval: not measurable
- QRS complex: usually
narrow, aberration may
occur
- Conduction: usually normal
through AV nodes and
ventricles
- Treatment:
- IV beta adrenergic blockers
- Calcium channel blockers
- Amiodarone
- Digitalis
- Catheter ablation therapy
- Cardioversion

18. Atrial fibrillation
• Originates from multiple ectopic
focus in the atrium, identified by
fibrillatory (f) waves
• ECG characteristics:
- Rate : Atrial rate 400-600b/min or
more; ventricular rate varies
depends on amount of block at
the AV node
- Rhythm: regular
- P wave: replaced by F-waves
- PR interval: not measurable
- QRS complex: usually normal,
aberration is common
- Conduction: disorganized and
irregular
- Treatment:
- IV beta adrenergic blockers
- Calcium channel blockers
- Amiodarone
- Digitalis
- Cardioversion

19. • Irritable focus in the AV
junction
• ECG characteristics:
- Rate : 60-100 b/min
- Rhythm: irregular because
of early beats
- P wave: may occur before,
during or after the QRS
complex and inverted
- PR interval: short usually
0.10 sec or less
- QRS complex: usually
normal but may be aberrant
- Conduction: retrograde
through atrai , normal
through ventricle
- Treatment:
- No treatment needed

20. • Occurs if sinus node rate falls below the automatic rate of AV
junctional pacemaker or in the presence of digitalis toxicity.
• Rate: Junctional rhythm (40-60b/min), Accelerated Junctional
rhythm (60-100b/min), Junctional tachycardia (100-250 b/min)
• Rhythm: regular
• P waves: may proceed or follow QRS
• PR interval: short, 0.10 sec or less
• QRS complex: usually normal
• Conduction: retrograde
• Treatment : atropine, beta-adrenergic blockers calcium channel
blockers, amiodarone, cardioversion

21. Premature ventricular contraction
• Originating in ectopic focus in the ventricles. It is
the premature occurrence of a QRS complex
which is wide and distorted in shape.
• Rate: 60-100 b/min
• Rhythm: irregular because of early beats
• P waves: not related to PVCs
• PR interval: absent before most PVCs, if present
PR interval is short
• QRS complex: wide, bizarre, usually greater than
0.12 sec
• Treatment : beta-adrenergic blockers,
procianamide, amiodarone, lidocaine

22. PVC

23. • Run of three or more PVCs occurs.
• Ectopic foci fire repetitively and the
ventricle control takes control as the
pacemaker
• Rate: ventricular rate is usually 100-
220 b/min
• Rhythm: usually regular but may be
slightly irregular
• P waves: buried in QRS complex or T
wave. VT may conduct retrograde to
the atria and p-wave can be seen
after each QRS.
• PR interval: not measurable
• QRS complex: wide, bizarre, usually
greater than 0.12 sec. Can be
monomorphic, polymorphic Torsado
de pointes.
• Conduction: impulse originates in
one ventricles and spreads by
muscle cell to cell conduction
through both ventricles. Retrograde
conduction
• Treatment :1. Hemodynamically
stable (with pulse), Amiodarone,
Lidocaine
• 2. Hemodynamically unstable (with
pulse), Cardioversion
• 3. Pulseless VT, Defibri;ation
• Others: Radiofrequency ablation,
implantable cardioverter defibrilator

24. Ventricular fibrillation

25. • Severe derangement of the
heart rhythm characterized
on ECG by irregular
undulations of varying
shapes and amplitude.
• Represents the firing of
multiple ectopic foci in the
ventricle.
• ECG Characteristics:
- Rate: Rapid, uncoordinated,
ineffective
- Rhythm: Choatic, irregular
- P-wave: not seen
- QRS complex: no formed
QRS complex seen; rapid,
irregular undurations
without any specific pattern.
This erratic electrical activity
can be coarse or fine
- Conduction: multiple ectopic
foci firing simultaneously in
ventricles and depolarizing
them irregularly and without
any organized pattern.
Ventricles are not
contracting.
• Treatment: immediate CPR
and advanced cardiac life
support measures with the
use of defibrillation and
definitive drug therapy.

26. Asystole
• Total absence of ventricle electrical activity.
• Occasionally P-wave can be seen
• No ventricular contraction occurs because depolarization
doesn’t occur
• Rate: None
• Rhythm: None
• P-wave: may be present if the sinus node is functioning
• PR-interval: None
• QRS complex: None
• Conduction: Atrial conduction may be normal if the sinus
node is functioning. No conduction in the ventricle
• Treatment: CPR with initiation of ACLS measures which
intubation, transcutaneous pacing and IV therapy with
epinephrine and atropine.

27. Conduction Abnormalities/Disorders
Heart Block
• Mobitz II heart block
• Type I/ Mobitz I/
Wenckebach heart
block
First
degree
AV block
Second
degree
AV block
Third
degree
AV block

29. First degree Atrioventricular Block
• Every impulse is conducted to the ventricles, but the
duration of AV conduction is prolonged.
• ECG Characteristics
• Rate: Can occur at any sinus rate, usually 60-100
b/min
• Rhythm: regular
• P wave: Normal, precede every QRS
• PR-interval: Greater than 0.20 sec
• QRS complex: usually normal, unless bundle of
branch block exists.
• Conduction: Normal through the atria, delayed
through the AV node, normal through the ventriccles.
• Treatment: No treatment required for first degree AV
block.

31. Second degree AV block Type I
• Type I second degree AV block
also termed as Mobitz I or
Wenckebach heart block
• Includes a gradual lengthening
of the PR interval followed by
missed or blocked beat
• ECG characteristics
- Rate: Atrial rate is normal, but
ventricle rate may be slower as
a result of nonconducted or
blocked QRS complex
- Rhythm: Irregular unless 2:1
conduction is present
- P-Waves: Normal. Some P
waves are not conducted to the
ventricles, but only one at a
time fails to conduct.
- PR- interval: Gradually
lengthening of PR interval in
consecutive beats.
- QRS complex: Usually normal
unless there is associated
bundle branch block
- Conduction: normal through the
atria, progressively delayed
through the AV node until an
impulse fails to conduct.
Ventricular conduction is
normal.
- Treatment: if the patient is
symptomatic, atropine is used
to increase HR or temporary
pacemaker may be needed.
- In case of asymptomatic, the
rhythm should be closely
observed with a transcutaneous
pacemaker on standby.

33. Second degree AV block Type II
• Type II second degree AV block also termed as Mobitz II heart block
• PR interval is constant and is greater than 0.20 sec, followed by
missed or blocked beat
• ECG characteristics
- Rate: Atrial rate is usually normal, but ventricle rate depends on
intrinsic rate and the degree of AV block
- Rhythm: Atrial rhythm is regular, but ventricle rhythm may be
irregular
- P-Waves: usually Normal and precede each QRS. Periodically a P
wave is not followed by a QRS complex.
- PR- interval: constant (prolonged greater than 0.20 sec), before all
conducted beats.
- QRS complex: Almost always wide because of association bundle
branch block.
- Conduction: normal through the atria and AV node, but intermittently
blocked in the bundle branch system and fails to reach the ventricles.
Conduction ratios can vary from 2:1 to only occasional blocked beats.
- Treatment: Pacemaker implatation

34. Second degree AV block Type II

35. Third degree AV block
• Third degree AV block or Complete heart block constitutes one form of
AV dissociation in which no impulses from the atria are conducted to
the ventricles.
• The atria are stimulated and contract independently of the ventricles.
The ventricular rhythm is an escape rhythm and the ectopic pacemaker
may be above or below the bifurcation of the bundle of his.
• ECG charachteristics
• Rate: Atrial rate is 60-100 b/min. the ventricular rate is 40-60b/min
• Rhythm: regular
• P-wave: Normal, but dissociative from QRS complexes
• QRS-complex: Normal if ventricles controlled by a Junctional
pacemaker, wide if controlled by a ventricular pacemaker
• Conduction: Normal through atria. All impulses are blocked at the AV
node or in the bundle of branches, so there is no conduction to the
ventricles. Conduction through the ventricles is normal if a junctional
escape rhythm occurs and is abnormally slow if a ventricular escape
rhythm occurs.
• Treatment: Pacemaker implantation.

36. Third degree AV block

37. Management of ARHYTHMIA
• Antiarrhythmic drugs
• Defibrilation
• Implantable cardioverter defibrilators
• Cardioversion
• Pacemaker
• Radiofrequency catheter ablation therapy