bradyaarythmias

1. MANAGEMENT OF BRADYARRYTHMIAS PRASAD K M

2. Normal Impulse Conduction Sinoatrial node AV node Bundle of His Bundle Branches Purkinje fibers For more presentations www.medicalppt.blogspot.com

3. Mechanism of Bradyarrhythmia • Failure of impulse formation . Failure of impulse conduction

4. SinusBradycardia • Sinus rate < 60 beats/min • Normal variant in many normal and older people • Causes: Trained athletes, during sleep, drugs (ß-blocker) , Hypothyriodism, CAD or SSS • Symptoms: • Most patients have no symptoms. • Severe bradycardia may cause dizziness, fatigue, palpitation, even syncope. • Needn’t specific therapy, If the patient has severe symptoms, planted an pacemaker may be needed.

5. Sinus Bradycardia • Deviation from NSR - Rate < 60 bpm For more presentations www.medicalppt.blogspot.com

6. Sinus Arrest or Sinus Standstill • Sinus arrest or standstill is recognized by a pause in the sinus rhythm. • Causes: myocardial ischemia, hypoxia, hyperkalemia, higher intracranial pressure, sinus node degeneration and some drugs (digitalis, ß-blocks). • Symptoms: dizziness, syncope • Therapy is same to SSS

7. Sinoatrial exit block (SAB) • SAB: Sinus pulse was blocked so it couldn’t active the atrium. • Causes: CAD, Myopathy, Myocarditis, digitalis toxicity, et al. • Symptoms: dizziness, fatigue, syncope • Therapy is same to SSS

8. Sinoatrial exit block (SAB) • Divided into three types: Type I, II, III • Only type II SAB can be recognized by EKG.

9. Sick Sinus Syndrome (SSS) • SSS: The function of sinus node was degenerated. SSS encompasses both disordered SA node automaticity and SA conduction. • Causes: CAD, SAN degeneration, myopathy, connective tissue disease, metabolic disease, tumor, trauma and congenital disease. • With marked sinus bradycardia, sinus arrest, sinus exit block or junctional escape rhythms • Bradycardia-tachycardia syndrome

10. Sick Sinus Syndrome (SSS) • EKG Recognition: • Sinus bradycardia, ≤40 bpm; • Sinus arrest > 3s • Type II SAB • Nonsinus tachyarrhythmia ( SVT, AF or Af • Instinct heart rate < 80bmp

12. Sick Sinus Syndrome (SSS) • Therapy: • Treat the etiology • Treat with drugs: anti-bradycardia agents, the effect of drug therapy is not good. • Artificial cardiac pacing.

13. Cardiac conduction block • Block position: Sinoatrial; intra-atrial; atrioventricular; intra-ventricular • Block degree • Type I: prolong the conductive time • Type II: partial block • Type III: complete block

14. Atrioventricular Block • AV block is a delay or failure in transmission of the cardiac impulse from atrium to ventricle. • Etiology: Atherosclerotic heart disease; myocarditis; rheumatic fever; cardiomyopathy; drug toxicity; electrolyte disturbance, collagen disease, lev’s disease.

15. Atrioventricular Block • AV block is a delay or failure in transmission of the cardiac impulse from atrium to ventricle. • Etiology: Atherosclerotic heart disease; myocarditis; rheumatic fever; cardiomyopathy; drug toxicity; electrolyte disturbance, collagen disease, lev’s disease.

16. AV Block • AV block is divided into three categories: • First-degree AV block • Second-degree AV block: further subdivided into type I and type II • Third-degree AV block: complete block

17. AV Block • Manifestations: • First-degree AV block: almost no symptoms; • Second degree AV block: palpitation, fatigue • Third degree AV block: Dizziness, agina, heart failure, lightheadedness, and syncope may cause by slow heart rate, Adams-Stokes Syndrome may occurs in sever case. • First heart sound varies in intensity, will appear booming first sound

18. 1st Degree AV Block / EKG Characteristics: Prolongation of the PR interval, which is constant All P waves are conducted

19. 2nd Degree AV Block Type 1 (Wenckebach) EKG Characteristics: Progressive prolongation of the PR interval until a P wave is not conducted. As the PR interval prolongs, the RR interval actually shortens Type 2 EKG Characteristics: Constant PR interval with intermittent failure to conduct

20. 3rd Degree (Complete) AV Block EKG Characteristics: No relationship between P waves and QRS complexes Relatively constant PP intervals and RR intervals Greater number of P waves than QRS complexes

21. AV Block • Treatment: • I or II degree AV block needn’t antibradycardia agent therapy • II degree II type and III degree AV block need antibradycardia agent therapy • Implant Pace Maker

22. Anti-bradycardia agents • Isoprenaline • Epinephrine • Atropine • Aminophylline

23. Pacemaker Components: Artificial cardiac pacemakers have two components: Power Source battery with pulse generator Electrode  delivers current to the heart a) Transvenous b) Epicardial c) Transthoracic d) Transcutaneous (external pacer)

24. In permanent pacemaker placement, the power source is implanted subcutaneously and the electrodes are run through the veins to inside the heart or through the subcutaneous tissue to the epicardial surface. In temporary pacemaker placement, the power source is external to the body and electrodes are placed in one of three ways: Transvenous to an intracardiac location Transthoracic via a needle puncture through the skin into the ventricular myocardium Transcutaneous with electrodes placed on the thoracic skin (most commonly used in emergency situations)

25. Pacer Rhythms The pulse generator can be designated to operate in one of two ways: 1) Fixed-Rate Mode (asynchronous or competitive) Produces an electrical signal at the preset rate regardless of the patient’s own intrinsic cardiac rhythm. Serious arrhythmias or ventricular fibrillation may occur if the pacemaker discharges during the vulnerable period (T wave).

26. Pacer Rhythms Demand Mode Generator has a sensing circuit which detects spontaneous cardiac activity and will discharge only if no cardiac depolarization is detected for a present interval; fires only when the natural heart rate drops below a set rate. Two Response Modes 1. Inhibited (most commonly used). Pulse generator is inhibited by the sensed cardiac activity and does not generate an impulse. 2. Triggered. Pacemaker detects the patient’s intrinsic cardiac activity and then discharges during the absolute refractory period.

27. Pacer Coding System

28. Pacer Coding System The most common type of pacemaker used – the ventricular demand inhibited response pacemaker designated as  VVI The dual pacers are becoming very popular, especially with CHF patients. Known as AV Sequential Pacers or Dual Chamber Pacers. Letter Coding  DDD

29. Power source Power Source Permanent pacemakers are powered by: Mercury – zinc battery (5-6 years life) Lithium battery (8-12 years life) Permanent pacers are preset for rates around 70. Manufacture supplies each unit with an identification card that the patient should carry with them.

30. Pacer Rhythms Temporary pacemakers are powered by: 9 volt radio-type battery Mode Settings a) Fixed b) Demand Rate settings a) 40-140 Stimulus Strength a) 0.2 to 20 mA

31. Pacemakers Ventricular pacemakers stimulate only the right ventricle, resulting in a rhythm that resembles IVR. Dual-chambered pacemakers (AV sequential pacemakers) stimulate the atria first and then the ventricles; benefits patients with marginal cardiac output that need the extra atrial kick.

32. Pacemakers Usually inserted into patients who have: 1. Chronic high-grade heart block 2. Sick sinus syndrome 3. Episodes of severe symptomatic bradycardia

33. Pacer Rhythms Indications for Emergency Pacing: Therapeutically Symptomatic Bradyarrhythmias that are symptomatic/unstable or not responding to other appropriate therapies. Prophylactically Conduction Defects High risk of developing sudden complete heart block or asystole. Symptomatic bradyarrhythmias should be treated with Atropine as a temporary measure to support cardiac rhythm until pacing is available.

34. Pacer Rhythms Any patient with acute myocardial infarction who has a new or age-indeterminant 2nd degree AV Block, Type 2; and, of course, 3rd degree AV block.

35. Pacer Rhythms Pacemaker Malfunction Permanent pacemaker malfunction can result from: Failure to properly sense the intrinsic cardiac rhythm Occurs when the voltage of the patient’s own intrinsic QRS complex is to low to be detected by the sensing circuit of the pacemaker. May cause the pacemaker to discharge during the T wave and trigger serious arrhythmias

36. Failure to effectively pace Occurs when tissue reaction around the electrode makes the myocardium insensitive to the electric discharge generated by the pacemaker. Failure to sense of pacemaker May be due to: 1. Battery Exhaustion 2. Catheter Wire Fracture

37. Artificial Pacemaker Rhythms

38. The most common indication for pacing A: Bifascicular / trifascicular Block B: AV block C: Sinus node disease D:Neurally mediated syncope E: Post AVN ablation H.ELMAHY 2010

39. Factors that help determine the need for brady pacemaker include: • A: Symptoms such as syncope / presyncope • B: bradyarrhythmia • C: symptoms correlated to bradyarrhythmia • D: symptoms not correlated to arrhythmia • E: none of the above H.ELMAHY 2010

40. Following AMI PPM is indicated in the presence of • A: persistent 2nd degree Type II AV block • B: transient 3rd degree block with LBBB • C: Persistent 3rd degree block • D: transient 2nd degree block with RBBB H.ELMAHY 2010

41. Classes of recommendation in ACC / AHA Guidelines H.ELMAHY 2010

42. PPM in AV BLOCK IS NOT INDICATED • When expected to resolve and / or unlikely to recur (e.g. Lyme disease or drug toxicity) • Asymptomatic 1st degree • Asymptomatic type I 2nd degree H.ELMAHY 2010

43. ACC/ AHA Class I indications for pacing in 3rd (and advanced 2nd ) degree AVB H.ELMAHY 2010

44. Pacing in chronic bi / trifascicular block INDICATED NOT INDICATED Intermittent 3rd degree block Advanced type II 2nd degree block Alternating BBB Fascicular block with out AV block or symptoms Fascicular block with 1st degree AV block without symptoms H.ELMAHY 2010

45. Factors that help determine the need for brady pacemaker include: • A: Symptoms such as syncope / presyncope • B: bradyarrhythmia • C: symptoms correlated to bradyarrhythmia • D: symptoms not correlated to arrhythmia • E: none of the above H.ELMAHY 2010

46. Take home message! There are only two indications for pacing (excluding pacing for heart failure): 1- symptoms + slow HR 2- high risk of symptoms + slow HR developing in the future H.ELMAHY 2010