Download Cardiac Arrhythmias

Cardiac Arrhythmias
Co-assistenten 2014-2015
Dr. L. Al tmimi
Department of anaesthesia
University Hospitals Leuven
1
Cardiac Arrhythmias
The normal ECG
• Regular narrow-complex rhythm
• Rate 60-100 bpm
• Each QRS complex is proceeded by a P wave
• P is upright in lead II & down going in lead aVR
2
Cardiac Arrhythmias
The normal ECG
• P wave: the sequential activation of the right & left atria.
• QRS complex: right & left ventricular depolarization
• ST-T wave: ventricular repolarization
• U wave: origin for this wave is not clear - but probably
represents "after depolarizations" in the ventricles
3
Cardiac Arrhythmias
The normal ECG
4
Cardiac Arrhythmias
The normal ECG
• PR interval: time from onset of atrial depolarization to onset of
ventricular depolarization.
• QRS duration: duration of ventricular muscle depolarization.
• QT interval: duration of ventricular depolarization &
repolarization
• RR interval: duration of ventricular cardiac.
• PP interval: an indicator of atrial rate.
5
Cardiac Arrhythmias
The normal ECG
• PR Interval: 0.12 - 0.20 sec
• QRS Duration: 0.06 - 0.10 sec
• QT Interval (QT < 0.40 sec at HR = 70)
• Poor Man's Guide to upper limits of QT: For HR = 70 bpm,
QT<0.40 sec; for every 10 bpm increase above 70 subtract
0.02 sec, and for every 10 bpm decrease below 70 add 0.02
sec. For example: QT < 0.38 @ 80 bpm QT < 0.42 @ 60
bpm
• Frontal Plane QRS Axis: +90° to -30° (in adult)
6
Cardiac Arrhythmias
The normal ECG
7
Cardiac Arrhythmias
The Sinoatrial node (SA node)
• Is the primary pacemaker of the heart
• These cells lies on the wall of the right atrium near superior
vena cave entrance
8
Cardiac Arrhythmias
Other cells exhibit automaticity are found in
• Along the sulcusterminalis
• In the coronary sinus ostium
• Within the AV junction
• In purkinje system
9
Cardiac Arrhythmias
The atrioventricular node (AV node)
• Specialized tissue lies between the atria and the ventricles
near the opening of coronary sinus.
• Conduct impulse from atria to ventricles.
10
Cardiac Arrhythmias
11
Cardiac Arrhythmias
Mechanism of arrhythmia
•
Abnormal automaticity
•
Abnormal cardiac conduction
•
Or both
12
Cardiac Arrhythmias
Causes of arrhythmia in operation room
are not always possible to determine because of :
• Physiologic imbalance
• Effects of multiple drugs
• Underlying myocardial disease
13
Cardiac Arrhythmias
Mechanism of arrhythmia
14
Cardiac Arrhythmias
Causes or risk factors of abnormal rhythm
• Ischemia
• Hypoxia
• Myocardial injury
• Sever hypothermia
• Excessive catecholamine exposure
• Acute electrolytes imbalance
• Drug toxicity
• Endocrine disease e.g. thyroid
• Others
15
Cardiac Arrhythmias
Sinus rhythms
• Sinus bradycardia
• Sinus tachycardia
• Sinus arrhythmia
16
Cardiac Arrhythmias
Sinus bradycardia
• pulse : <60/min; rhythm: regular
• P wave: normal, QRS : normal
• If the HR<40 mostly not good tolerated
• Treatment:
•
according to the causes
• Atropine, Isoprenaline, P.M.
17
Cardiac Arrhythmias
Sinus bradycardia
18
Cardiac Arrhythmias
Causes of bradycardia
• medication e.g. neostigmin, myoplegin , etc.
• diseases e.g. hypothyroidism, after MI
• hypothermia & hypoxia
• halothane or gas anaesthesia in children
• vagal stimuli
• increased intracranial pressure
• others
19
Cardiac Arrhythmias
Sinus tachycardia
• Heart rate >100 to 180/min
• Rhythm is regular
• P wave is normal
• QRS is also : normal
• Treatment depends on the causes
• Beta blocker
20
Cardiac Arrhythmias
Causes of sinus tachycardia
• light anaesthesia, hypovolemia
• pain, anxiety
• hyperthyroidism
• medication e.g. atropine
• fever & anaemia
• etc.
21
Cardiac Arrhythmias
Sinus arrhythmia
• Normal increase in HR occurs during inspiration, more seen
in children
• Rhythm is irregular
• Normal QRS after each wave
• No treatment is required
22
Cardiac Arrhythmias
Atrial rhythms
• Premature atrial complexes
• Atrial flutter
• Atrial fibrillation
• Supraventricular tachycardia & nodal rhythm
• Wolff-Parkinson-White (WPW)
23
Cardiac Arrhythmias
Premature atrial complexes
• Occur as single or repetitive events and have unifocal or
multifocal origins.
• The ectopic P wave is often hidden in the ST-T wave of the
preceding beat.
24
Cardiac Arrhythmias
Atrial flutter
• Atrial rate between 250-350 bpm
• A saw-tooth appearance (F waves) is in leads II, III, aVF &V1.
• Variable degrees of AV block is
25
Cardiac Arrhythmias
Atrial flutter
• Usually results from a re-entrant circuit located totally within
the atrial wall.
• It is generally associated with heart disease - e.g. rheumatic
heart disease (with mitral stenosis).
• Hemodynamic compromise may warrant electrical
cardioversion.
26
Cardiac Arrhythmias
Atrial flutter treatment
• Digoxine
• Synchronal defibrillation
• Beta-blocker
• Verapamil
• Amiodarone
27
Cardiac Arrhythmias
Atrial fibrillation (AF)
• Most common arrhythmia; risk increases with age.
• Irregular fibrillating atrial waves at a rate of 300-600 bpm,
best seen in leads II, III, aVF &V1.
• Absence of P waves
• Fibrillation is may caused by numerous microentry circuits
within the atrial muscle.
•
Ventricular rate is irregularly irregular with AV block
28
Cardiac Arrhythmias
Atrial fibrillation (AF)
29
Cardiac Arrhythmias
Clinical significance of AF
• AF is usually associated with chronic heart disease.
• Also in hyperthyroidism, pulmonary embolism & COPD
• DC may be required in the acute cases with hemodynamic
compromise.
• Anticoagulation is always necessary
30
Cardiac Arrhythmias
AF Differential diagnosis includes
• Atrial flutter with an irregular ventricular response
• Multifocal atrial tachycardia which is usually irregular
Rx:
• Digoxine
• Amiodarone
• Beta-blocker
• Verapamil
• Synchronal defibrillation
31
Cardiac Arrhythmias
Supraventricular tachycardia (SVT)
•
Is a rapid rhythm of the heart in which the origin of the
electrical signal is either the atria or the AV node.
32
Cardiac Arrhythmias
Possible symptoms of SVT
• Pulse rate of 140 – 200/ min or faster.
• Palpitations & Angina may be triggered by an episode of SVT.
• Dizziness & Dyspnoea
Treatment
• Verapamil, beta blocker, or even Amiodarone
• Synchronic defibrillation in some occasion
33
Cardiac Arrhythmias
Junctional rhythm
• HR : variable, 40 tot 180/min
• Rhythm : regular
• P wave: High nodal before QRS
Mid nodal in QRS
Low nodal after QRS
• QRS : normal
34
Cardiac Arrhythmias
Junctional tachycardia
• The AV node initiates electrical activity in the heart.
• An ECG of a Junctional rhythm commonly presents with an
inverted "P" wave due AV nodal origin of electrical signal
35
Cardiac Arrhythmias
Treatment of junctional rhythm
• No treatment is usually needed unless low cardiac output
• Atropine or isoprenaline if junctional bradycardia
• Deeping of the anaesthesia
• Beta-blocker in nodal tachycardia
36
Cardiac Arrhythmias
Wolff-Parkinson-White (WPW) syndrome
• Is a congenital abnormality.
• Presence of abnormal conductive tissue between the atria
and the ventricles.
• Is often associated with supraventricular tachycardia (SVT).
37
Cardiac Arrhythmias
Wolff-Parkinson-White (WPW) syndrome
38
Cardiac Arrhythmias
Wolff-Parkinson-White (WPW) syndrome
• Presence of a short PR interval (<120 ms)
• A wide QRS complex of longer than 120 milliseconds with a
slurred onset of the QRS waveform producing a delta wave in
the early part of QRS
• Secondary ST-T wave changes
39
Cardiac Arrhythmias
Treatment of WPW
• Asymptomatic patients with the WPW shown are not treated.
Drug therapy: according to the arrhythmia associated with WPW.
Digoxine is contraindicated in WPW with AF. Amiodarone or
procainamide may help.
Electrical ablation
• Symptomatic tachyarrhythmias
• Occupations in which the development of symptoms would put
themselves or others at risk (e.g. truck drivers or airline pilots
• Selected asymptomatic patients
Surgical ablation
40
Cardiac Arrhythmias
Ventricular arrhythmias
• Ventricular extrasystole
• Ventricular tachycardia
• Ventricular fibrillation
41
Cardiac Arrhythmias
Ventricular extrasystole
• Also called premature ventricular contraction (PVC) or
ventricular premature beat (VPB)
• Is a form of irregular heart beat in which the ventricle
contracts prematurely
42
Cardiac Arrhythmias
Possible triggers for ventricular extrasystole ( PVC )
• Anxiety/Stress
• Chocolate ,Caffeine, Cocaine or other stimulant
• Calcium/magnesium imbalance
• Dehydration , Exercise, Hormonal imbalance
• Hypercapnia (CO2 poisoning)
• Hyperstimulation of the Vagus nerve
• Lack of sleep/exhaustion
43
Cardiac Arrhythmias
What is this arrhythmia?
Ventricular tachycardia
usually caused by reentry, and most commonly seen in
patients following myocardial infarction.
44
Cardiac Arrhythmias
Ventricular tachycardia
• HR : 100 tot 300/min
• Rhythm: regular
• P top : through VT
• QRS :wide complex
45
Cardiac Arrhythmias
Ventricular tachycardia
• VT can be monomorphic or polymorphic with prolong QT
interval (torsade de pointes )
46
Cardiac Arrhythmias
Ventricular tachycardia (VT) treatment
• Synchronous defibrillation
• Xylocaïne
• Bretyllium
• Amiodarone
• Beta-blocker
47
Cardiac Arrhythmias
Ventricular arrhythmias: “ Torsade de pointes” Rx:
• Withdrawal of any offending drugs and correction of
electrolyte abnormalities
• Intravenous magnesium sulfate
• Potassium repletion to 4.5 to 5 mmol/liter
• Beta blockers combined with cardiac pacing as acute therapy
for patients with TdP and sinus bradycardia
• Intravenous lidocaine
• Non-synchronous defibrillation
48
Cardiac Arrhythmias
Ventricular tachycardia
49
Cardiac Arrhythmias
Ventricular fibrillation
• Ventricular fibrillation has been described as "chaotic
asynchronous fractionated activity of the heart" (Moe et al.
1964).
• No cardiac output
• Treatment is : CPR
50
Cardiac Arrhythmias
Rhythms Produced by Conduction Block
• AV Block (relatively common)
– 1st degree AV block
– 2nd degree AV block Type 1
– 2nd degree AV block Type 2
– 3rd degree AV block
• SA Block (relatively rare)
51
Cardiac Arrhythmias
1st Degree AV Block
• Prolongation of the PR interval, which is constant.
• All P waves are conducted
52
Cardiac Arrhythmias
2nd Degree AV Block: Mobitz I or Wenckebach block
•
Progressive prolongation of the PR interval until a P wave is
not conducted.
53
Cardiac Arrhythmias
2nd Degree AV Block: Mobitz II
• Constant PR interval with intermittent failure to conduct
54
Cardiac Arrhythmias
3rd Degree (Complete) AV Block
• No relationship between P waves and QRS complexes
•
Relatively constant PP intervals and RR intervals
•
Greater number of P waves than QRS complexes
55
Cardiac Arrhythmias
Bundle branch block
56
Cardiac Arrhythmias
Right bundle branch block
57
Cardiac Arrhythmias
Left bundle branch block
58
Cardiac Arrhythmias
Left bundle branch block
59
Cardiac Arrhythmias
Left bundle branch block
Patient with LBBB in whom a PA catheter is being placed
may need availability of transcutaneous PM because of the risk
of inducing Right BBB & thus complete heart block during
passage of the PA catheter
60
Cardiac Arrhythmias
success
61