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Ant arrhythmic drugs
This document discusses anti-arrhythmic drugs and their mechanisms and classifications. It summarizes that anti-arrhythmic drugs work by blocking sodium, potassium, calcium, or beta receptor channels to normalize abnormal electrical conduction in the heart and treat arrhythmias. The drugs are classified into four main classes based on their ion channel targets and actions. Class I drugs block sodium channels, Class II block beta receptors, Class III prolong repolarization by blocking potassium channels, and Class IV block calcium channels. Each class has subgroups that differ in their specific channel blocking profiles and effects on heart rhythms.
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Ant arrhythmic drugs
- 1. Anti-Arrhythmic Drugs By:- Dr.Manish Pal Singh, Associate Professor 1AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA Source*- www.physio-pedia.com
- 2. Cardiac Arrhythmia: ❑ Cardiacarrhythmias results from alterations in the orderly sequence of depolarization followed by repolarization in the heart. ❑ Arrhythmias are the most important cause of sudden cardiac death. ❑ Abnormal automaticity or impaired conduction or both underline cardiac arrhythmias. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 2 Source*-https://www.ohsu.edu/doernbecher/pediatric- electrophysiology-and-arrhythmia
- 3. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 3 Divided into five phases (0,1,2,3,4) • Phase 0 – rapid depolarization • Phase 1 – early repolarization • Phase 2 – plateau phase • Phase 3 – rapid repolarization • Phase 4 – resting phase, diastolic depolarization Source*- https://www.google.com/uFbasicmedicalkey.com
- 4. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 4 ARRHYTHMIA Abnormal impulse conduction Abnormal impulse generation Triggered activity Arrhythmia may be occur due to- • Abnormal pacemaker activity •Shift of the pacemaker from SA node to another place in the heart. • Block at different points in the spread of the impulses through the heart. •Abnormal pathways of impulse transmission through the heart. •Spontaneous generation of spurious impulses in almost any part of the heart.
- 5. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 5 Abnormal impulse conduction
- 6. ❑ Conduction Block:- ▪Due to depression of impulse conduction at AV node & bundle of His, due to vagal influence or ischemia. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 6 1st degree heart block – slowed conduction 2nd degree block – some supraventricular complex not conducted 3rd degree block – no supraventricular complex are conducted Premature contraction
- 7. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 7 Re-Entry Moments- “Circus Movements Source*- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.slideshare.net
- 8. ➢ Due toabnormality of conduction , an impulse may recirculate in the heart and causes repetitive activation without the need for any new impulse to be generated. ➢ When the normal cardiac impulses in the normal heart has traveled through the extent of the ventricles, it has no place to go because all the ventricles muscle is refractory & can’t conduct the impulse further. Therefore, that impulses dies & the heart awaits a new AP to begin in the SA node. ➢ Circus movement type:- A premature impulse temporarily blocked in one direction by refractory tissue, makes a one-way transit around an obstacle finds the original spot in an advanced state of recovery and rexicites it, setting up recurrent activation of adjacent myocardium. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 8
- 9. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 9 Accessory tract pathway Source*- https://www.google.com/url Accessory pathway in the heart called Bundle of Kent
- 10. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 10 Important Types of Arrhythmia :- 1. ES (Extra systoles)- premature beats 2. PVST (Paroxysmal supraventricular tachycardia)- Due to circus movement type of Re-entry or accessory pathway 3. AFL (Atrial flutter)- Due to re entry circuit in right atrium 4. AF (Atrial Fibrillation)- Due to electrophysiological in homogeneity of atrial fibers. 5. Ventricular Tachycardia (VT)- Due to either discharge from ectopic focus or reentry circuits 6. Torsades de Points- Polymorphic VT with rapid asynchronous complex, twisting along the baseline on ECG with long QT interval 7. Ventricular fibrillation - Grossly irregular, rapid & fractionated action of ventricles – resulting in in coordinated contraction of ventricles with loss of pumping function.
- 11. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 11 Source*- https://www.google.com/Fen.wikipedia.org Approachable Targets of Anti-arrhythmic Drugs
- 12. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 12 Targets mechanisms of Anti-arrhythmic Drugs
- 13. Classification of Anti-arrhythmicdrugs AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 13Source*- https://www.google.com/Fbpspubs.onlinelibrary.wiley.com (Na+-channel blocker) (β blocker) K+ channel blocker (Ca+- channel blocker)
- 14. CLASS-I- Drugs: AGRA PUBLICPHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 14 They act on open Na+ channels or inactivated only They ↓ automaticity in non-nodal tissues (atria, ventricles, and purkinje fibers)
- 15. Subclass- IA: ❑ Theoldest anti-arrhythmic drugs- ‘Quinidine & Procainamide’. ❑ They are open state Na+- channel blockers, which suppress A-V conduction & prolong refractoriness. ❑ Slowing the rate of rise in phase 0 ❑ They prolong action potential & ERP ❑ ↓the slope of Phase 4 spontaneous depolarization ❑ ↑ QRS & QT interval AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 15
- 16. ADR’s: • Cinchonism” –tinnitus, vertigo, • headache, nausea & blurred vision. • Gastrointestinal intolerance. • Hypersensitivity reactions. Drug Interactions: ▪ Quinidine can interact the plasma concentration of digoxin, which may in turn lead to signs and symptoms of digitalis toxicity. ▪ Cimitidine increases hepatic metabolism of quinidine. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 16Source*- https://www.google.com/imgres?imgurl
- 17. Subclass- IB: ❑ Thesedrugs block Na+- channels more in the inactivated than in the open state. ❑ They shorten Phase 3 repolarization. ❑ the duration of the cardiac action potential ❑ Prolong phase 4. ❑ Lidocaine used as local anaesthetic drug, in addition it is a popular antiarrhythmic drug. ❑ Its cardiac action is suppression oof Of automaticity in ectopic foci. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 17
- 18. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 18 Source*- =https%3A%2F%2Fdir.indiamart.com%2Fimpcat%2Flidocaine. ADR’s:- Neurological effects- Drowsiness, Slurred speech, Confusion and convulsions. Contraindications:- Lidocaine is contraindicated in the presence of second and third degree heart block, since it may increase the degree of block and can abolish the idioventricular Pacemaker responsible for maintaining the cardiac rhythm. Drug Interactions:- Proponolol increases its toxicity. The myocardial depressant effect of lidocaine is enhanced by phenytoin administration.
- 19. Subclass- IC: ❑ Theseare most potent Na+- channel blockers with more prominent action on open state & the longest recovery times. ❑ markedly slow Phase 0 depolarization. ❑ slow conduction in the myocardial tissue ❑ minor effects on the duration of action potential and ERP ❑ reduce automaticity by increasing threshold potential rather than decreasing slope of Phase 4 depolarization. ❑ They have profound effect on His-Purkinje as well as accessory pathway conduction. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 19
- 20. ❑ Flecainide produceADR’s like- • torsades de point, • Visual disturbances & headache • Digoxin toxicity • Contraindiaction- cardiogenic shock ❑ Propafenone produce ADR’s like- • proarrhythmogenic effect, • metallic taste & constipation • Contraindication- Heart failure AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 20 Source*- https://www.google.com/imgres?imgurlt
- 21. CLASS-II ❑ Its suppressadrenergically mediated ectopic activity. ❑ Depress phase 4 depolarization ❑ Depress automaticity ❑ Prolong AV conduction -↑ ERP -Prolong PR interval - ↓ HR ❑ ↓ contractility ❑ Use inappropriate sinus tachycardia Sympathetic mediated arrhythmias AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 21
- 22. CLASS-III ❑ K+ channelblockers . ❑ This class is prolongation of repolarization; AP is widened & ERP is increased. ❑ Prolong QT & PR AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 22 AMIDARONE----- Next PPT
- 23. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 23 Iodine – containing Block of delayed rectifier K+ ↓HR & AV nodal conduction QT prolongation Preferentially block Na+ channel Arrhythmic death in post MI ADR- heart block, pulmonary, hepatitis, dermatitis Interaction – digoxin, diltiazem & quinidine Uses =VF, VT & AF
- 24. CLASS-IV ❑ The primaryaction to inhibit L-type Ca++- channel mediated slow channel inward current. ❑ ↓ Rate of phase 4 in SA / AV node ❑ Slow conduction – prolong ERP ❑ Phase 0 upstroke ↓ ❑ The basic action of verapamil is to depress Ca++ mediated depolarization. AGRA PUBLIC PHARMACY COLLEGE, ARTONI, AGRA, UP, INDIA 24
- 25. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 25 Source*- www.slideshare.net%2Fnasertadvi%2Fantiarrhythmic-drugs
- 26. AGRA PUBLIC PHARMACYCOLLEGE, ARTONI, AGRA, UP, INDIA 26 Source*- https%3A%2F%2Fwww.diabetesselfmanagement.com%2