1. By Dr. Zahoor
CARDIAC ARRHYTHMIA

2. 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

3. CONDUCTIVE TISSUE OF HEART

4. 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)

5. 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

6. CARDIAC ARRHYTHMIA Normal heart rate (HR) 60-100/min
HR > 100/min is called Tachycardia
HR < 60/min is called Bradycardia

7. CARDIAC ARRHYTHMIA Arrhythmia may be 1. Supraventricular
i- Sinus (SA Node)
ii- Atrial
iii- Atrioventricular nodal re-entrant
tachycardia (AVNRT)
2. Ventricular

8. 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

9. 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

10. CAUSES OF SINUS BRADYCARDIA

11. 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

12. CAUSES OF SINUS TACHYCARDIA
- Some pathological causes

13. ii. ATRIAL TACHYARRHYTHMIA
Atrial Tachyarrhythmia may be 1. Atrial extra systole/premature beat/ectopic beat 2. Atrial Tachycardia 3. Atrial flutter 4. Atrial fibrillation

14. 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

15. 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

16. ATRIAL TACHYARRHYTHMIA
2. Atrial tachycardia
Heart rate is /min, it is due to atrial automaticity, digoxin toxicity
ECG produces narrow complex tachycardia (QRS is narrow) with abnormal P wave

17. 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

18. 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

19. 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

20. 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

21. ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation
ECG shows no P-wave but fibrillation waves. QRS complex is normal but coming at irregular interval

22. 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)

23. ATRIAL TACHYARRHYTHMIA
4. Atrial Fibrillation Causes

24. 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

25. 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 – when AF is present < 3months, patient is young, no structural heart disease

26. 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)

27. 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%

28. SUPRAVENTRICULAR TACHYCARDIA (SVT)
iii. Atrioventricular nodal re-entrant tachycardia (AVNRT)- Junctional-arryhythmias
These tachycardia are due to re-entry in a circuit involving AV node.
It produces regular tachycardia with a rate of /min. Episode may last from few seconds to many hours

29. SUPRAVENTRICULAR TACHYCARDIA (SVT)
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
HR 180/min

30. 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

32. 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)

33. VENTRICULAR TACHYARRYTHMIA
They are
1. Ventricular ectopic beats
2. Ventricular Tachycardia (VT)
3. Ventricular Fibrillation (VF)

34. 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

35. VENTRICULAR TACHYARRYTHMIA
Ventricular ectopic beat (extra systole, premature beat)
QRS Complex (arrows) are broad, bizarre with no preceding P wave

36. 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

37. 2. VENTRICULAR TACHYCARDIA (VT)
ECG shows tachycardia with broad, abnormal QRS complex with a rate of > 120/min

38. VENTRICULAR TACHYCARDIA (VT)
Common causes of VT
Acute MI
Cardiomyopathy
Chronic IHD with poor LV function

39. 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

40. 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

41. 3. Ventricular Fibrillation (VF)

42. 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

43. Prolonged PR interval 0.26 second
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

44. 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

45. 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

46. 2. Mobitz type II – second degree AV block
Here PR interval remains constant but
some P wave are not conducted

47. 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

48. 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

49. Thank you