1. Cardiac Arrhythmias: An Update
Dr N.M.Gandhi
Consultant Cardiologist
Spire Gatwick Park Hospital, Horley
East Surrey Hospital, Redhill
Royal Sussex County Hospital, Brighton

2. Objectives
Identify common arrhythmias encountered by the family physician
Discuss initial Mg options
AF and Ventricular arrhythmias case studies
Which patients needs to be referred? ECG examples

3. THE CONDUCTION SYSTEM
We use the term Conduction System to describe the electrical pathway of an electrical impulse that causes a heart beat.

4. Atrial Depolarization
After the SA node fires, the resulting depolarization wave passes through the right and left atria, which produces the P-wave on the surface EKG and stimulates atrial contraction.

5. Ventricular Depolarization
The impulse passes quickly through the bundle of His, the left and right bundle branches, and the Purkinje fibers, leading to depolarization and contraction of the ventricles.
The QRS complex on the EKG represents the depolarization of the ventricular muscle mass.

6. CARDIAC ARRHYTHMIAS
Disturbances of either :
Impulse generation
Impulse propagation

7. ELECTROPHYSIOLOGIC PRINCIPLES
BRADYARRHYTHMIAS
SINUS NODE DYSFUNCTION
AV CONDUCTION DISTURBANCES
TACHYARRHYTMIAS
ATRIAL TACHYCARDIAS
VENTRICULAR TACHYCARDIA A R H Y T M I S

8. Bradyarrhythmias Impulse formation: Impulse conduction:
Decreased automaticity: Sinus bradycardia
Impulse conduction:
Conduction blocks: 1º, 2º, 3º AV blocks

9. Tachyarrythmias Impulse formation Impulse conduction
Enhanced automaticity:
Sinus node: sinus tachycardia
Ectopic focus: Ectopic atrial tachycardia
Triggered activity
Early afterdepolarization: torsades de pointes
Digitalis-induced SVT
Impulse conduction
Reentry: Paroxysmal SVT, atrial flutter and fibrilation, ventricular tachycardia and fibrillation.

10. Normal Sinus Rhythm
Implies normal sequence of conduction, originating in the sinus node and proceeding to the ventricles via the AV node and His-Purkinje system.
EKG Characteristics: Regular narrow-complex rhythm
Rate bpm
Each QRS complex is proceeded by a P wave
P wave is upright in lead II & downgoing in lead aVR

11. PAC Benign, common cause of perceived irregular rhythm
Can cause sxs: “skipping” beats, palpitations
No treatment, reassurance
With sxs, may advise to stop smoking, decrease caffeine and ETOH
Can use beta-blockers to reduce frequency

12. PVC
Extremely common throughout the population, both with and without heart disease
Usually asymptomatic, except rarely dizziness or fatigue in patients that have frequent PVCs and significant LV dysfunction

13. PVC Reassurance Optimize cardiac and pulmonary disease management
Beta-blocker
Ablation in a small number of cases

14. Bradyarrhythmias Impulse formation: Impulse conduction:
Decreased automaticity: Sinus bradycardia
Impulse conduction:
Conduction blocks: 1º, 2º, 3º AV blocks

15. Sinus Bradycardia HR< 60 bpm; every QRS narrow, preceded by p wave
Can be normal in well-conditioned athletes
HR can be 30 bpm in adults during sleep, with up to 2 sec pauses

16. Sinus arrhythmia
Usually respiratory--Increase in heart rate during inspiration
Exaggerated in children, young adults and athletes—decreases with age
Usually asymptomatic, no treatment or referral
Can be non-respiratory, often in normal or diseased heart, seen in digitalis toxicity
Referral may be necessary if not clearly respiratory, history of heart disease

17. Sick Sinus Syndrome All result in bradycardia
Sinus bradycardia with a sinus pause
Often result of tachy-brady syndrome: where a burst of atrial tachycardia (such as afib) is then followed by a long, symptomatic sinus pause/arrest, with no breakthrough junctional rhythm.

18. 1st Degree AV Block PR interval >200ms
If accompanied by wide QRS, refer to cardiology, high risk of progression to 2nd and 3rd deg block
Otherwise, benign if asymptomatic

19. 2nd Degree AV Block Mobitz type I (Wenckebach)
Progressive PR longation, with eventual non-conduction of a p wave
May be in 2:1 or 3:1

20. 2nd degree block Type II (Mobitz 2)
Normal PR intervals with sudden failure of a p wave to conduct
Usually below AV node and accompanied by BBB or fascicular block
Often causes pre/syncope; exercise worsens sxs
Generally need pacing, possibly urgently if symptomatic

21. 3rd Degree AV Block
Complete AV disassociation, HR is a ventricular rate
Will often cause dizziness, syncope, angina, heart failure
Can degenerate to Vtach and Vfib
Will need pacing, urgent referral

22. Tachyarrythmias Impulse formation Impulse conduction
Enhanced automaticity:
Sinus node: sinus tachycardia
Ectopic focus: Ectopic atrial tachycardia
Triggered activity
Early afterdepolarization: torsades de pointes
Digitalis-induced SVT
Impulse conduction
Reentry: Paroxysmal SVT, atrial flutter and fibrilation, ventricular tachycardia and fibrillation.

23. SUPRAVENTRICULAR T. Sinus Tachycardia Atrial flutter
Atrial fibrilation
Paroxysmal Supraventricular
Multifocal Atrial T.
Preexcitation Syndrome (Wolff-Parkinson-white Sy.)

24. Sinus tachycardia HR > 100 bpm, regular
Often difficult to distinguish p and t waves

25. Paroxysmal Supraventricular T.
Sudden onset and termination
Atrial rates of 140 to 250 /min
Normal QRS complexes
The mechanism is most often reentry.

26. Paroxysmal Supraventricular Tachycardia
Refers to supraventricular tachycardia other than afib, aflutter and MAT
Usually due to reentry—AVNRT or AVRT

27. PSVT
CSM or adenosine commonly terminate the arrhythmia, esp, AVRT or AVNRT
Can also use CCB or beta blockers to terminate, if available
Counsel to avoid triggers, caffeine, Etoh, pseudoephedrine, stress

28. Multifocal Atrial T.
Is due to enchanced automaticity within the atria, resulting in abnormal discharges from several ectopic foci
Most often occurs in the setting of severe pulmonary disease and hypoxemia.
EKG: irregular rhythm with multiple (at leats 3) P waves morphologies

29. Atrial flutter
Is caracterized by rapid coarse “sawtooth” appearing atrial activity, at rate of 250 to 350 x min.
Many of these fast impulses reach the AV node during its refractory period, so that the ventricular rate is generally lower.
Frequently it degenerates into atrial fibrilation
The most expiditious therapy is electrical cardioversion, which is undertaken directly for highly symptomatic patients. (to revert chronic refractory atrial flutter that has not responded to other approaches)

30. Preexcitation Syndrome
Wolff-Parkinson-White Syndrome
EKG: Although different types of bypass tracts have been identified, the bundle of Kent, is the most common and can usually conduct in both the anterograde and retrograde directions.

31. Atrial Fibrillation Irregular rhythm Absence of definite p waves
Narrow QRS
Can be accompanied by rapid ventricular response

32. Atrial fibrillation--management
Rhythm vs Rate control—if onset is within last hours, may be able to arrange cardioversion—use heparin around procedure
Need TEE if valvular disease (high risk of thrombus)
If unable to definitely conclude onset in last hours: need 4-6 weeks of anticoagulation prior to cardioversion, and warfarin for 4-12 weeks after

33. Atrial Fibrillation: Clinical Problems
Embolism and stroke (presumably due to LA clot)
Acute hospitalization with onset of symptoms
Anticoagulation, especially in older patients (> 75 yr.)
Congestive heart failure
Loss of AV synchrony
Loss of atrial “kick”
Rate-related cardiomyopathy due to rapid ventricular response
Rate-related atrial myopathy and dilatation
Chronic symptoms and reduced sense of well-being

34. AF: Medical Management
Treatment of underlying cause
Ventricular rate control
Anticoagulation
Antiarrhythmics with a view to restore sinus rhythm

35. Control of Ventricular Rate in Atrial Fibrillation
Betablockers
Calcium channel blockers
Verapamil, diltiazem
Digoxin
Amiodarone

36. Anticoagulation

37. Anticoagulation
Assessment of bleeding risk should be part of the clinical assessment of AF patients prior to starting anticoagulation
Antithrombotic benefits and potential bleeding risks of long-term coagulation should be explained and discussed with the patient
Aim for a target INR of between 2.0 and 3.0
NICE 2006
NOTES FOR PRESENTERS
Refer to NICE guideline – pages 22 and 23
In order to provide adequate thromboprophylaxis with minimal risk of bleeding, current clinical practice aims for a target INR of between 2.0 and 3.0; INRs higher than 3.0 are associated with increases in bleeding, and INRs lower than 2.0 are associated with increases in stroke risk.

38. CHADS 2 scoring
CCF
Hypertension
Age > 75
Diabetes
Stroke/TIA
1 point
1point
2 points
Any patients with AF with a score of =/>2 would benefit from being on Warfarin

39. Cardioversion

40. Cardioversion Cardioversion results in SR in at least 90% of cases
SR is only maintained in 30-50% at one year
Class 1a, 1c and III agents increase likelihood of maintained SR from 30-50% to 50-70% at one year

41. Follow-up Reassess the need for anticoagulation at each review
Follow-up after cardioversion should take place at 1 month, and the frequency of subsequent reviews should be tailored to the patient
Reassess the need for anticoagulation at each review
NOTES FOR PRESENTERS
For further details, refer to the NICE guideline – page 25.
The commonest reason for referral for specialist investigation or intervention is failed medical therapy

42. Catheter Ablation for AF

44. AF Ablation
Success rates – approx 70% but may require repeat procedure
Often increase in symptoms for first 3-6 months after procedure does not indicate failure
Risks
– damage to existing conduction mandating pacing
Cardiac perforation/tamponade
Bleeding
Stroke/thromboembolism
Death

45. Catheter Ablation: Indications
Symptomatic patients
Refractory to Antiarrhythmics
Medical therapy contraindicated due to co-morbidities or intolerance
NICE 2006

46. Which AF patients need Specialist Referral?
Patients with:
- WPW syndrome
- Uncontrolled ventricular rate (> 200/min)
- Tachy-brady syndrome
- For rhythm control strategy
- CCF
- Intolerant to Drugs
- Invasive options

47. VENTRICULAR ARRHYTHMIAS
Ventricular tachycardia
Torsades De Pointes
Ventricular fibrillation

48. Ventricular tachycardia
Is divided in 2 categories:
If it persist for more than 30 seconds “sustained VT”
Less than 30 seconds: “nonsustained VT”
Symptoms vary depending on the duration.
Major manifestations are hypotension and loss of consciousness.

49. Non-sustained ventricular tachycardia
Need to exclude heart disease with Echo and stress testing
May need anti-arrhythmia treatment if sxs
In presence of heart disease, increased risk of sudden death
Need referral for EPS and/or prolonged Holter monitoring
ICD may be life saving

50. Torsades De Pointes Varying amplitudes of the QRS.
It can be produced by afterdepolarizations (triggered activity).
Particularly in prolonged QT interval.
Occur with some drugs (quinidine), electrolite disturbances, and congenital prolongation of the QT interval.

51. Specialist Referral
ECG Examples

63. Contact...
* * Fax: * Phone: Spire ESH , ext.6333