4-ANTIARRHYTHMIC DRUGS CARDIAC ARRHYTHMIAS All arrhythmia Result From 2-Abnormalities of impulse formation 2-Abnormalities of impulse conduction. 3-Both. Types of arrhythmia : 1. Sinus tachycardia. 2. Sinus bradycardia 3. Extra systoles 4. Atrial flutter 5. Atrial fibrillation 6. Paroxysmal atrial tachycardia 7. Paroxysmal ventricular tachycardia 8. Ventricular fibrillation

9. Heart block 8. Bundle branch block N.B. Wolf-Parkinson-White Syndrome (WPW): accessory atrioventricular pathway which conduct more

ANTIARRHYTHMIC DRUGS  Non-pharmacological treatment are preferred because: 1-Arrhythmogenic effect of the drugs used in treatment of arrhythmias. 2-Efficacy of these methods. Non Pharmacological techniques Ablation technique.. Implantable cardiovector defibrillator . Artificial pacemaker.

A-Mechanistic Classifications CLASS I (SODIUM CHANNEL BLOCKERS) Ia: Quinidine Ib: Lidocaine CLASS II (BETA-BLOCKERS) CLASS III (POTASSIUM CHANNEL BLOCKERS) Amiodarone CLASS IV  Calcium channel blockers e.g. verapamil, diltiazem( not nifidipine cus it will caus reflex sympathetic stimulation ) Potassium channel openers ( indirect C.C.B) e.g. adenosine

B-Therapeutic Classification of Antiarrhythmic Drugs Supraventricular arrhythmias: verapamil digoxin beta-blockers Ventricular arrhythmias: Lidocaine Supraventicular and ventricular arrhytmias: Amiodarone Quinidine

CLASS Ia ANTIARRHYTHMICS QUINIDINE. Pharmacodynamics Fast sodium channels blocker atropine like action alpha receptor blocking effect

Pharmacological Effects  Effects on the cardiovascular system  Cardiac effects -ve inotropic effect. ↓ excitability ↓ automaticity ENHANCE conductivity in the A-V node ( cus it has atropine like effect) and bundle of His ^ this effect is dangerous can cause paradoxical techacardiya causin death Effect on blood vessels and BP: vasodilatation hypotension with large dose

Therapeutic Indications Atrial fibrillation (of less than 6 months duration). Patient should be digitalized before quinidine? to prevent the possible occurrence of "Paradoxical tachycardia". Atrial flutter less active than in atrial fibrillation can be used when digitalis fails. Paroxysmal atrial tachycardia. Extrasystoles. Atrial and ventricular. Ventricular tachycardias. Maintenance of sinus rhythm after successful direct current cardioversion.

Side Effects and Toxicity  Idiosyncrasy : abnormal individual response Cinchonism: حس إن أجراس تدق باذنه وجاي من اسم الشجرة ringing of the ear Embolism Paradoxical tachycardia. Quinidine syncope. Hypotension: particularly if given intravenously.

Precautions before giving QUINIDINE 1- @ 1st give testing dose 2-digoxin (digitalize the heart) 3-give anti coagulant 4-u shouldn't give QUINIDINE for Old standing atrial fibrillation ( AF) more than 6 months

Old standing atrial fibrillation. Congestive heart failure. Contraindications Complete A.V block Old standing atrial fibrillation. Congestive heart failure. Hypotension. Hypersensitivity. Myasthenia gravis.

PROCAINAMIDE Pharmacological Effects Similar to quinidine It has weak anticholinergic effects. has a ganglion blocking effect. It doesn’t have alpha blocking activity Therapeutic Uses more in Ventricular arrhythmias

CLASS Ib ANTIARRHYTHMICS LIDOCAINE** the least cardio toxic of antiarrhythmic Therapeutic Uses Ideal drug for treatment of ventricular arrhythmias . *Given IV only PHENYTOIN (Diphenylhydantoin, DPH) 1-treating epileptic seizures 2-ventricular arrhythmias. Adverse Effects Gum hyperplasyia gingival hyperplasia

CLASS III AMIODARONE**لا يخلو امتحان من سؤال عن هذا الدواء CLASS II BETA-ADRENOCEPTOR BLOCKERS يستعمل في حالات معينة Therapeutic Uses : Supraventricular arrhythmias drug of choice for chest pain and arrhythmias of mitral valve prolapse CLASS III AMIODARONE**لا يخلو امتحان من سؤال عن هذا الدواء POTASSIUM CHANNEL BLOCKERS Broad-spectrum antiarrhythmic drug ( all types of arrhythmia ) Adverse Effects Corneal microdeposists disturb thyroid function photosensitivity pulmonary fibrosis myopathy peripheral neuropathy hepatotoxicity

CLASS IV CALCIUM CHANNEL BLOCKERS verapamil and diltiazem Mechanism of Action: delaying conduction in A.V node OTHER ANTIARRHYTHMICS DIGOXIN: Delay conduction in A.V node ADENOSINE MAGNESIUM SULFATE ELECTRIC SHOCK THERAPY  Direct current electric shock will depolarize the heart , then S.A node will work , after that give quinidine

CLINICAL APPLICATIONS OF ANTIARRHYTHMIC DRUGS Atrial Fibrillation  Emergency Treatment Digitalis IV is the drug of choice. Cardioversion  Non-emergency Treatment Digitalis is given orally. Quinidine Atrial Flutter Emergency Treatment I.V. digitalis  Non-Emergency Treatment Digitalis is given orally

Wolf-Parkinson-White (WPW) Syndrome Amiodarone ,sotalol Cardioversion. Junctional Tachycardias Vagotonic maneuvers ..( stimulate vagal nerve) I.V. verapamil ADENOSINE

Ventricular Tachycardia  Emergency Treatment Lidocaine ( IV) is the first choice I.V. amiodarone Cardioversion Prophylaxis I.V. drips quinidine (72 hrs) Oral quinidine should be continued for at least 3 months especially if there is acute myocardial infarction.

Ventricular fibrillation Torsade de pointes MAGNESIUM SULFATE Artificial pacemaker Ventricular fibrillation  Lidocaine procainamide amiodarone Bradyarrhythmias and Heart Block Cardiac pacemaker Atropine I.V. . Hydrocortisone I.V. ( if there’s inflammation in conducting tissue)