Cardiac Arrhythmias: An Update

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

4. Atrial Depolarization

5. Ventricular Depolarization

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 R H Y T H M I A S

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

9. Tachyarrythmias • Impulse formation • Enhancedautomaticity: • Sinusnode: sinustachycardia • Ectopicfocus: Ectopic atrial tachycardia • Triggeredactivity • Earlyafterdepolarization: torsades de pointes • Digitalis-induced SVT • Impulse conduction • Reentry: Paroxysmal SVT, atrial flutter and fibrilation, ventricular tachycardia and fibrillation.

10. Normal Sinus Rhythm www.uptodate.com 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 60-100 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: • 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 • Enhancedautomaticity: • Sinusnode: sinustachycardia • Ectopicfocus: Ectopic atrial tachycardia • Triggeredactivity • Earlyafterdepolarization: torsades de pointes • Digitalis-induced SVT • Impulse conduction • Reentry: Paroxysmal SVT, atrial flutter and fibrilation, ventricular tachycardia and fibrillation.

23. SUPRAVENTRICULAR T. • SinusTachycardia • Atrial flutter • Atrial fibrilation • ParoxysmalSupraventricular • Multifocal Atrial T. • PreexcitationSyndrome(Wolff-Parkinson-whiteSy.)

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 • Iscaracterizedbyrapidcoarse “sawtooth” appearing atrial activity, at rate of 250 to 350 x min. • Many of thesefast impulses reachthe AV nodeduringitsrefractoryperiod, so thatthe ventricular rateisgenerallylower. • Frequentlyitdegeneratesinto atrial fibrilation • Themostexpiditioustherapyiselectricalcardioversion, whichisundertakendirectlyforhighlysymptomaticpatients. (torevertchronicrefractory atrial flutterthat has not responded tootherapproaches)

30. Preexcitation Syndrome • Wolff-Parkinson-White Syndrome • EKG: Althoughdifferenttypes of bypass tractshavebeenidentified, thebundle of Kent, isthemostcommon and can usuallyconduct in boththeanterograde 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 24-48 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 24-48 hours: need 4-6 weeks of anticoagulation prior to cardioversion, and warfarin for 4-12 weeks after

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

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

35. 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

36. CHADS 2 scoring • Any patients with AF with a score of =/>2 would benefit from being on Warfarin

37. 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

38. Follow-up • 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

39. VENTRICULAR ARRHYTHMIAS • Ventricular tachycardia • Torsades De Pointes • Ventricular fibrillation

40. 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.

41. 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

42. 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.

43. Specialist Referral ECG Examples