Antiarrhythmic

 

1- Classification of Vaughan Williams:

* Class I: sodium channel inhibitors (+ membrane stabilizing effect)

– Ia: quinidine; disopyramide (Rythmodan)

– Ib: lidocaine; phenytoin; mexiletine

– Ic: Cibenzoline, propafenone (Rythmol®) flecainide

* Class II: Beta-blockers

* Class III: inhibitors of potassium flux

– Amiodarone (Cordarone)

– Sotalol (Sotalex®)

– Bretylium

* Class IV: calcium channel blockers

– Verapamil (Isoptine)

– Diltiazem (Tildiem®)

– Bepridil

2- Action Sites:

* Atrioventricular node: Class II; Class IV; digitalis

* Atrial Ventricular Myocardium &: class Ia and Ic.

* Ventricular myocardium: Class Ib

* Atrial Ventricular Myocardium & & atrioventricular node: Class III; propafenone (Rythmol)

Action potential non-automatic cardiac cells

Action potential non-automatic cardiac cells

3- Amiodarone:

A- Indication:

– Adjustment of AF, flutter or atrial tachysystole

– Preventive or curative treatment of ventricular arrhythmias

– Arrhythmias WPW syndrome

– Preventive treatment of angina

B- cons-indications:

Sinus node dysfunction

– AVB II or III unaided

– Thyroid Dysfunction; iodine allergy

– Association with drugs that prolong the QT.

C- Side effects:

– Hepatitis

– Thyroid Dysfunction

– Interstitial lung disease

– Peripheral neuropathy

– Torsades de pointes

– Other: photosensitivity, reversible corneal deposit

4- Class I:

A- quinidine:

1- Indications:

– Prevention of recurrence fibrillation or flutter after return to sinus rhythm

– Prevention of paroxysmal supraventricular tachycardia crises

– Treatment and prevention of ESA and ESV

2- Side effects:

– Idiosyncrasie fever, hypotension, QT prolongation

– Effect proarythmyque: torsade de pointes, BAV, BSA, ESV

– Dizziness, deafness, tinnitus

B- Lidocaine:

1- Indications:

Correction and prevention of ventricular arrhythmias in the acute phase of MI.

2- adverse drug effects:

– Neurological: tremor, confusion, convulsion

– Hypotension, bradycardia

5- General characteristics:

A- Class Ia:

– Increases the duration of PA

– QT high (risk TDP)

– Widening of the QRS

– Flattening of the T wave

– Negative inotropic effect

– Act sue the atria and ventricles.

B- Class Ib:

– Reduction of the duration of PA

– Unchanged ECG

– Unchanged inotropic

– Exclusive ventricular Action

C- Class Ic:

– Enlargement of QRS with a possible BB

– Unchanged QT

– Negative inotropic effect

– Action in the atria and ventricles.

D- Amiodarone:

– Increased the duration of the AP and refractory periods.

– QT elevation; the sinus rate decreases; PR increases; T wave flattening; U wave

– Do not change the inotropic

– Action at all levels

6- Associations:

A- prohibited Associations:

– Two AA of the same family

– II + IV

– III + IV

B- AF or flutter Prevention:

– Ia + digoxin

– Ia + beta blocker

C- Preventing recurrence TV:

Amiodarone + beta blocker

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