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CLASSIFICATION OF ANTI ARRHYTHMIC DRUGS

CLASSIFICATION OF ANTI ARRHYTHMIC DRUGS. www.anaesthesia.co.in anaesthesia.co.in@gmail.com. DENOSUMAB. - 31. - 29. Action potential. Phase 0 Na current Phase 1 Transient outward current Phase 2,3 Ca current vs k current Phase 4 Pacemaker current. Na channel blockers.

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CLASSIFICATION OF ANTI ARRHYTHMIC DRUGS

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  1. CLASSIFICATION OF ANTI ARRHYTHMIC DRUGS www.anaesthesia.co.in anaesthesia.co.in@gmail.com

  2. DENOSUMAB

  3. - 31 - 29

  4. Action potential • Phase 0 • Na current • Phase 1 • Transient outward current • Phase 2,3 • Ca current vs k current • Phase 4 • Pacemaker current

  5. Na channel blockers Beta blockers K channel blockers Ca channel blockers

  6. Class I drugs

  7. Class IA QUINIDINE, PROCAINAMIDE, DISOPYRAMIDE • Affinity for activated Na-channel • Also have class III effects (prolong APD/ QT - TdP) • Negative inotrope

  8. Class IB LIDOCAINE (IV), MEXILETINE (PO) • Affinity for inactivated Na-channel • Little effect on atrial tissue • Greatest effect on diseased/ ischemic ventricle

  9. Class IC FLECAINIDE, PROPAFENONE • Slow kinetics, affinity for activated Na-channel • Most potent Na-blocking effect • Greatest effect on ECG • Negative inotrope

  10. Class II METOPROLOL, ATENOLOL, PROPRANOLOL, CARVEDILOL, ESMOLOL • Beta-1 receptor antagonism • Slow sinus rate • Prolong AV node conduction and refractoriness • Inhibit automaticity • Block cardiac sympathetic innervation and effect of circulating catecholamines

  11. Class III SOTALOL, DOFETILIDE, IBUTILIDE, AMIODARONE • Amiodarone has property of all 4 classes • Block cardiac potassium channels • Prolong refractoriness/ APD

  12. Class IV VERAPAMIL AND DILTIAZEM • Does not include the dihydropyridines • Blockade of cardiac L-type calcium channel -> decrease cytosolic calcium • Prolong AV node conduction and refractoriness • Mild sinus slowing effect • Mild reduction in automaticity

  13. The Sicilian Gambitt

  14. TACHYARRHYTHMIAS SUPRA VENTRICULAR & VENTICULAR

  15. Classification: Appearance of QRS complexes • Narrow complex tachycardias (QRS < 0.12 s ) • Sinus tachycardia • Atrial fibrillation • Atrial flutter • AVNRT • Accessory pathway mediated tachycardia • Atrial tachycardia • MAT • Junctional tachycardia • Wide complex tachycardias (QRS > 0.12 s ) • VT • SVT with aberrancy • Pre excited tachycardias

  16. Sinus Tachycardia • HR>100 bpm • Rhythm: regular • Treat the cause

  17. Re-entry SVT: AVNRT & AVRT • AVNRT: Most common form of PSVT • Ventricular rate – 150 to 250 bpm • Types: Typical:Antegrade conduction through slow pathway Atypical:Antegrade conduction through the fast pathway Termination:Block in the slow pathway

  18. PSVT: Management • Unstable? Cardioversion: 10 – 50 J • Stable? • Acute therapy Vagal maneuver Adenosine: 6 mg…12 mg…12 mg Diltiazem • Chronic therapy Beta-blocker, CCB, digoxin Catheter ablation

  19. Conversion with adenosine

  20. Premature atrial contractions

  21. Atrial flutter Organised atrial rhythm Atrial rate: 250 – 350 bpm

  22. Atrial fibrillation • Uncoordinated atrial activation • Deterioration of atrial mechanical function • Causes: Cardiac / thoracic surgery Electrocution Pericarditis / Myocarditis MI Hyperthyroidism Alcoholism ( Holiday heart syndrome ) With other heart disease: CAD, VHD (MS), cardiomyopathy Neurogenic AF

  23. AF: Types • Lone AF: No clinical / ECG evidence of cardiopulmonary disease, ≤ 60 yrs • Idiopathic AF • Recurrent: ≥ 2 episodes of AF • Paroxysmal: Self terminating • Persistent: ≥ 7 days and requires cardioversion for termination • Permanent: Unsuccessful cardioversion

  24. AF: Clinical evaluation • History: symptoms, type, onset, frequency, duration, precipitating factors, underlying heart disease • Investigations: ECG, CXR, Echo (TEE), TFT

  25. Treatment • Unstable: Electrical Cardioversion: 100 J • Stable: Rate control ± rhythm control

  26. Rate control • Why rate control? Symptomatic relief Myocardial oxygen demand Tachycardia related cardiomyopathy • Adequate ventricular rate control? 60 - 80 bpm (at rest) 90 - 115 bpm (moderate exercise) Rawles JM,Br Heart J 1990 , Resnekov LBr Heart J 1971;33:339–50.

  27. Rate control – Acute AF

  28. Rate control – Persistent AF

  29. Why rhythm control??? • Relief of symptoms • Prevention of thromboembolism • Tachyarrhythmia induced myocardial remodeling and HF

  30. AF ≤ 7 days

  31. AF ≥ 7 days

  32. Drugs to maintain sinus rhythm

  33. Risk factors for ischemic stroke in AF • High • H/O of prior thromboembolism • Rheumatic MS • Prosthetic heart valves • Moderate • Age ≥ 75 • LVEF ≤ 35 • CHF • HTN • DM • Low • Females • Age 65 – 74 • CAD • Thyrotixicosis

  34. Antithrombotic therapy • Antithrombotic therapy to all patients with AF, except those with lone AF • Target INR of 2 to 3 in patients at high risk of stroke • AF due to RHD / prosthetic valves – Target INR > 2 - 3 • Contraindication: Aspirin in a dose of 325 mg daily

  35. Antithrombotic therapy in AF • > 75 yrs – INR 1.6 – 2.5 • Interrupt anticoagulation for a period of up to 1 week for surgical or diagnostic procedures that carry a risk of bleeding, without substituting heparin in patients with AF who do not have mechanical prosthetic heart valves • Aspirin optional for primary prevention of stroke in patients < 60 years of age without heart disease or risk factors for thromboembolism (lone AF)

  36. Cardioversion • Electrical: 100 J • Pharmacological • Simple • Less efficacious

  37. Cardioversion & Thromboembolism • Risk of thromboembolism - 1% and 5% in case-control series • LAA thrombus in TEE - High risk of thromboembolism after cardioversion of AF or atrial flutter • Treated with anticoagulant for at least 3 to 4 weeks before and after cardioversion

  38. Prophylaxis during elective cardioversion • Administer anticoagulation therapy regardless of the method used to restore sinus rhythm • Anticoagulate patients with AF >48 h or of unknown duration, for at least 3 to 4 weeks before and after cardioversion (INR 2 to 3)

  39. AF with instability • Heparin bolus – infusion to prolong aPTT to 1.5 – 2 times normal • Oral anticoagulation 3 – 4 wks post cardioversion

  40. Alternative to routine preanticoagulation before elective cardioversion Screen by TEE for LAA thrombus • No thrombus • IV heparin bolus – infusion till aPTT 1.5 – 2 times normal • Oral AC ( INR 2 – 3 ) for 3 – 4 wks post cardioversion • Thrombus • AC 3 – 4 wks before and after cardioversion

  41. Junctional rhythms • Arrhythmia of the AV junction • Types: High nodal Mid nodal Low nodal • ECG: Variable, regular HR Abnormal p wave Varying PR interval

  42. Junctional rhythm: Significance • 20 % of patients under anesthesia • Halogenated anesthetic agents • Upto 30 % decrease in BP in those with heart disease

  43. Junctional rhythm: Treatment • Reverts spontaneously • Pharmacological • Atropine • Ephedrine • Isoprenaline • Pacing

  44. VENTRICULAR TACHYARRHYTHMIAS

  45. VPC

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