Download cardiac arrhythmia

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Basal metabolic rate wikipedia, lookup

G protein-gated ion channel wikipedia, lookup

Cardiac output wikipedia, lookup

Cardiac action potential wikipedia, lookup

Heart rate wikipedia, lookup

Artificial cardiac pacemaker wikipedia, lookup

Management of atrial fibrillation wikipedia, lookup

Defibrillation wikipedia, lookup

Electrocardiography wikipedia, lookup

Transcript
By Dr. Zahoor
1
CARDIAC ARRHYTHMIA
First we will have quick look at the
physiology
 SA Node is the pace maker of the heart
and is under control of ANS
(Sympathetic and Parasympathetic)
 Heart has its conductive tissue
SA Node – Internodal fibers – AV Node
– Bundle of HIS – Bundle branches
(RBB and LBB) – Purkinje fibers
2
CONDUCTIVE TISSUE OF HEART
3
CARDIAC ARRHYTHMIA

If the sinus rate (SA Node) becomes unduly
slow then lower center may assume the
role of pacemaker, this is known as ESCAPE
RHYTHM

Impulse may arise from
- AV Node (Nodal Rhythm) or
HIS bundle (Junctional Rhythm) or
Ventricles (Idioventricular Rhythm)
4
CARDIAC ARRHYTHMIA
What is CARDIAC ARRHYTHMIA?
 It is the disturbance of electrical rhythm
of the heart.
Why Arrhythmia occur?
 They are often due to structural heart
disease, but may also occur due to
abnormal conduction
5
CARDIAC ARRHYTHMIA
Normal heart rate (HR)
60-100/min
 HR > 100/min is called Tachycardia
 HR < 60/min is called Bradycardia

6
CARDIAC ARRHYTHMIA

Arrhythmia may be
1. Supraventricular
i- Sinus (SA Node)
ii- Atrial
iii- Atrioventricular nodal re-entrant
tachycardia (AVNRT)
2. Ventricular
7
CARDIAC ARRHYTHMIA
Important
 Supraventricular rhythm produces
narrow QRS complex. Why?
Because ventricles are depolarized
through AV Node and Bundle of His.
 Ventricular rhythm produce wide,
bizarre QRS complex because
ventricles are depolarized in an
abnormal sequence
8
SUPRAVENTRICULAR
ARRHYTHMIA
i. SA NODE
Sinus Arrhythmia
 Heart rate increases during inspiration and
slows during expiration, it is called sinus
arrhythmia. More commonly seen in
children. It is physiological.
Sinus Bradycardia
 Sinus rate < 60/min, may occur in healthy
people at rest, athlete or it may be
pathological e.g. hypothyroidism, increased
intracranial pressure
9
CAUSES OF SINUS BRADYCARDIA
10
SUPRAVENTRICULAR
ARRHYTHMIA
Sinus Tachycardia - Physiological
 Sinus rate > 100/min usually due to
increased sympathetic activity
associated with emotion, exercise,
pregnancy
OR
It may be pathological e.g.
hyperthyroidism, heart failure
11
CAUSES OF SINUS TACHYCARDIA
- Some pathological causes
12
ii. ATRIAL TACHYARRHYTHMIA
Atrial Tachyarrhythmia may be
1. Atrial extra systole/premature
beat/ectopic beat
2. Atrial Tachycardia
3. Atrial flutter
4. Atrial fibrillation
13
ATRIAL TACHYARRHYTHMIA
1. Atrial extra systole
 When there is atrial extra systole, it usually causes
no symptoms, but can give the sensation of miss
beat or abnormally strong beat
Atrial Ectopic Beats – 3rd 4th and 6th complexes
14
ATRIAL TACHYARRHYTHMIA
1. Atrial extra systole
 ECG shows premature beat, P wave
has different morphology. Why?
Because atria are activated from an
abnormal site ( but QRS is normal)
 Effect – usually no consequence but
very frequent atrial ectopic beat may
lead to AF
 Treatment – beta blockers can be used
15
ATRIAL TACHYARRHYTHMIA
2. Atrial tachycardia
 Heart rate is 140-250/min, it is due to atrial
automaticity, digoxin toxicity

ECG produces narrow complex tachycardia
(QRS is narrow) with abnormal P wave
16
ATRIAL TACHYARRHYTHMIA
2. Atrial Tachycardia
Treatment
 Beta blockers – they reduce automaticity
 If ventricular response is rapid, A..V node
blocking drugs (calcium blockers e.g.
verapamil)
 Cathetor ablation to target the ectopic site in
case of recurrent atrial tachycardia
17
ATRIAL TACHYARRHYTHMIA
3. Atrial Flutter
 Atrial rate is approximately 300/min and
usually associated with 2:1, 3:1 or 4:1 A.V
block (with heart rate of 150, 100, or 75/min)

ECG shows saw – toothed flutter waves. It is
narrow complex tachycardia
18
ATRIAL TACHYARRHYTHMIA
3. Atrial Flutter
Management
 Beta blocker, verapamil, digoxin can be
used to control the ventricular rate
 To restore sinus rhythm, we use direct
current, DC cardio version or
Amiodarone IV
 Catheter ablation – 90% chance of
complete cure
19
ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation (AF)
 It is due to abnormal automatic firing in the
atria
 In AF – atria beat rapidly
 Atrial rate 350 to 500/min but in
uncoordinated and ineffective manner
 The ventricles are activated irregularly at a
rate determined by conduction through the
AV Node. This produces irregularly
irregular pulse
20
ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation

ECG shows no P-wave but fibrillation
waves. QRS complex is normal but
coming at irregular interval
21
ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation
 It may be
1. Paroxysmal (intermittent, self terminating
episode)
2. Persistent (prolonged episode)
3. Permanent
 AF causes are – coronary artery disease,
valvular heart disease, hypertension,
hyperthyroidism, alcohol, idiopathic (lone
AF)
22
ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation
Causes
23
ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation
Do ECG, echo cardiogram, thyroid function
test
Management
1. Paroxysmal AF
 Paroxysmal AF may not require treatment.
Beta blockers are used
 Other drugs used are digoxin, verapamil to
limit the heart rate by blocking AV node
 Ablation is used for ectopic focus
24
ATRIAL TACHYARRHYTHMIA
Management
2. Persistent AF and 3. Permanent AF
 There are two ways to treat
i). Rhythm control – to restore and maintain
sinus rhythm by DC cardioversion (after the
administration of anti coagulants)
Indication – Attempts to restore and
maintain sinus rhythm are most successful
when AF is present < 3months, patient is
young, no structural heart disease
25
ATRIAL TACHYARRHYTHMIA
Management ( cont )
2. Persistent and Permanent AF (cont)
ii). Rate control using treatment to
control ventricular rate and prevent
embolic complication
 Drugs used are digoxin, beta blocker,
calcium antagonist e.g. verapamil or
diltiazem (they act by increasing AV
node delay)
26
ATRIAL TACHYARRHYTHMIA
Prevention of thromboembolism in AF
 Loss of atrial contraction and left atrial
dilatation causes stasis of blood in left
atrium and may lead to thrombus
formation. It predisposes the patient to the
stroke.
 Treatment advised
- Warfarin – it decreases the risk by 62%
- Aspirin – it decreases the risk by 22%
27
SUPRAVENTRICULAR
TACHYCARDIA (SVT)
iii. Atrioventricular nodal re-entrant
tachycardia (AVNRT)- Junctionalarryhythmias
 These tachycardia are due to re-entry in
a circuit involving AV node.
 It produces regular tachycardia with a
rate of 120-240/min. Episode may last
from few seconds to many hours
28
SUPRAVENTRICULAR
TACHYCARDIA (SVT)
HR 180/min
Management
 Carotid sinus pressure – it increases vagal tone
 IV adenosine or verapamil will restore sinus rhythm in most
cases
 Beta blockers
 DC cardio version if SVT with hemodynamic compromise
 Catheter abalation
29
WOLFF – PARKINSON WHITE
SYNDROME (WPW Syndrome)

In WPW Syndrome, there is abnormal
band of conductive tissue which
connects atria to the ventricles. It is like
Purkinje tissue that conducts very
rapidly and is called accessory pathway
30
31
WOLFF – PARKINSON WHITE
SYNDROME (WPW Syndrome)
ECG shows short PR and slurring of QRS
complex called Delta wave
Treatment
 Carotid sinus pressure
 IV adenosine
 Catheter abalation in symptomatic patient
For prophylaxis
- Amiodarone, flecainide (they slow the
conduction in the accessory pathway)

32
VENTRICULAR TACHYARRYTHMIA

They are
1. Ventricular ectopic beats
2. Ventricular Tachycardia (VT)
3. Ventricular Fibrillation (VF)
33
VENTRICULAR TACHYARRYTHMIA
1. Ventricular ectopic beat (extra systole,
premature beat)
 In ventricular ectopic beat, QRS is broad
and bizarre because ventricles are
activated by abnormal focus
 QRS may be unifocal (identical), when they
arise from single ectopic focus or QRS may
be multi focal (varying morphology) as they
arise from multiple foci
34
VENTRICULAR TACHYARRYTHMIA
Ventricular ectopic beat (extra systole,
premature beat)
QRS Complex (arrows) are broad, bizarre with no preceding P
wave
35
VENTRICULAR TACHYARRYTHMIA
Ventricle ectopic beat may occur in
Healthy subject – more prominent at rest and
disappear at exercise
 Treatment in symptomatic patient - beta blocker
Ventricular ectopic beat in Heart Disease
 Occur during acute MI
 Heart failure
 Digoxin toxicity
 Mitral valve prolapse
36
2. VENTRICULAR TACHYCARDIA (VT)

ECG shows tachycardia with broad, abnormal
QRS complex with a rate of > 120/min
37
VENTRICULAR TACHYCARDIA (VT)
Common causes of VT
 Acute MI
 Cardiomyopathy
 Chronic IHD with poor LV function
38
VENTRICULAR TACHYCARDIA (VT)
Treatment of VT
 Synchronized DC cardio version shock, if
systolic BP < 90mmHg
 If VT is well tolerated then
- IV Amiodarone as bolus and then continuous
infusion
- IV lidocaine
Note – Correct hypokalaemia, hypomagnesaemia,
acidosis and hypoxaemia
39
TORSADES DEPOINTES
(VENTRICULAR TACHYCARDIA)

This type of VT occurs in patients who
have prolonged QT interval
(hypocalcaemia, hypomagnesaemia,
hypokalaemia)

ECG shows bradycardia with long QT
interval followed by VT, rapid, irregular
QRS complex
40
3. Ventricular Fibrillation (VF)
41
3. Ventricular Fibrillation (VF)
It is life threatening, medical emergency
There is very rapid, irregular ventricular
activation with no pumping of blood
 Patient is pulseless, becomes rapidly
unconscious and respiration ceases
(Cardiac arrest)
 Can lead to death in minutes
Treatment
1- Defibrillation
2- CPR


42
HEART BLOCKS
First degree AV Block
 In first degree heart block, AV conduction is
delayed. PR interval is prolonged > 0.2
second
 It rarely causes symptoms
First Degree AV Block
Prolonged PR interval 0.26 second
43
HEART BLOCKS
Second degree AV Block
 In this condition, some impulse from atria to
ventricle fail to conduct, therefore, drop beat
occur.
 There are two types
1. Wenchebach’s Phenomenon or Mobitz
type I
2. Mobitz type II
44
1. Wenckebach’s phenomenon
or Mobitz type I
Here PR interval progressively
increases, until P wave is not
followed by QRS (drop beat)
Wenchebach’s Phenomenon or Mobitz type I
45
2. Mobitz type II – second degree AV block
Here PR interval remains constant but
some P wave are not conducted
46
HEART BLOCKS
Third degree (complete) AV block
 There is no conduction taking place through
AV node, therefore atria and ventricle beat
independently

Atrial rate may be 80/min, ventricular rate
38/min
47
AV BLOCK
Treatment
 For second and third degree AV block
 Atropine 0.6mg IV, repeated as necessary
 If it fails – temporary pacemaker
 Permanent pacemaker is indicated in
patients with chronic Mobitz type II second
degree heart block and third degree AV
block because of risk of asystole and
sudden death
48
Thank you
49