Pharmacology and effect of amiodarone, pharmacological effects of amiodarone are

pharmachologic effect].

Mechanism of action of amiodarone: blockade of sodium, calcium, potassium channels, non-competitive blockade and receptor action.

It significantly inhibits repolarization and prolongs APD and ERP of atrial muscle, ventricular muscle, and conduction system

It can reduce the automaticity of the sinus node and the His-Pur system, increase the threshold of ventricular fibrillation, and reduce the conductivity of Purkinje fibers and the sinus node.

It has a relaxing effect on smooth muscles such as coronary blood vessels, dilates coronary blood vessels, reduces peripheral vascular resistance, reduces myocardial work and oxygen consumption, and protects ischemic myocardium. There is little negative inotropic effect.

Antiarrhythmic effect.

A prolongation of the heart fiber action potential phase course to reduce potassium influx (Vaughar Williams classification class), an effect independent of heart rate.

b Decreases sinus node automaticity, as it can lead to bradycardia that does not respond to atropine.

c Non-competitive - and - adrenergic inhibitions.

d Slows conduction in the sinus, intra-atrium, and nodal areas (more pronounced when the heart rhythm is fast).

e does not alter intraventricular conduction.

f Prolongs the refractory period and decreases myocardial excitability in the atria, nodal area, and ventricles.

g Slows down the conduction of the atrioventricular bypass pathway and prolongs its refractory period.

Antianginal effect.

a Lowers peripheral resistance and slows heart rate to reduce oxygen uptake.

b Non-competitive - and - adrenergic antagonism.

c Acts directly on the smooth muscles of the myocardial arteries to increase coronary output.

d Reduce aortic pressure and peripheral resistance and maintain cardiac output.

3. Other no obvious negative inotropic effects.

Indications: Oral is suitable for atrial premature contractions and premature ventricular contractions; Recurrent paroxysmal supraventricular tachycardia, atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation can prevent reversal, and can also prevent the onset of pre-excitation syndrome with supraventricular arrhythmias and maintenance of atrial fibrillation or atrial flutter after electrical reversion. Secondly, it has an antianginal effect.

Intravenous injection is indicated for paroxysmal supraventricular tachycardia, especially in patients with preexcitation syndrome, and for ventricular tachycardia that does not respond to lidocaine**.

It is suitable for atrial premature contractions, ventricular premature contractions, transient atrial tachycardia, and retroactive supraventricular tachycardia, and has poor efficacy for persistent atrial fibrillation or flutter, which is not as good as quinidine. Not satisfied with the effect of maintaining sinus rhythm after cardioversion of atrial fibrillation. Intravenous injection is indicated for paroxysmal supraventricular tachycardia, especially in patients with preexcitation syndrome.

It is also used in patients with ventricular tachycardia who do not respond to lidocaine**. This product is a broad-spectrum antiarrhythmic drug. The efficacy is significant, but it is currently listed as a second-line antiarrhythmic drug because of the large number of anti-arrhythmic drugs.

For severe arrhythmias that are ineffective or inappropriate for others:

1 atrial arrhythmias (maintenance of atrial flutter, atrial fibrillation and post-conversion sinus rhythm);

2 Nodal arrhythmias;

3 Ventricular arrhythmias (** life-threatening premature ventricular systoles and ventricular tachycardia and prevention of ventricular tachyarrhythmia or ventricular fibrillation);

4 Arrhythmias with w-p-w syndrome.

According to its pharmacological characteristics, amiodarone is suitable for the above arrhythmias, especially those with structural heart disease (coronary insufficiency and heart failure).

Answer]: The pharmacological effect of amiodarone is mainly to block sodium, calcium, and potassium channels, and only disturb non-competitive blocking and receptors; It significantly inhibits repolarization and prolongs APD and ERP of atrial muscle, ventricular muscle, and conduction systemIt can reduce the automaticity of the sinus node and Xiyipu system, increase the threshold of ventricular fibrillation, and reduce the conductivity of Pukenye fiber and sinus node, so the correct answer is a.

The first skin of the answer is slow]: b

Amiodarone is an antiarrhythmic drug, and its main electrophysiological effect is to prolong the action potential and effective refractory period of the central muscle tissue in each part, which is conducive to eliminating reentry agitation.

Answer] :d amiodarone is a benzofuran derivative, which belongs to a class of broad-spectrum antiarrhythmic drugs that mainly prolong the action potential, and its main mechanism of action is to prolong the action potential time course and effective refractory period of the atrium, atrioventricular refractory node and ventricle by blocking potassium ion outflow, so that the difference between the refractory period of the Lie manuscript between cardiomyocytes is reduced, the action potential tends to be consistent, and the establishment of micro-reentry is prevented, which is conducive to eliminating the reentry activation and inhibiting atrioventricular fibrillation and slowing down the automaticity of the sinus node. Slows conduction, slows the heart rate, and terminates ventricular tachycardia. Therefore, choose D.

Test center: The role and use of amiodarone.

Answer] Amiodarone :d prolongs the 3-phase duration of the action potential of the heart fiber to reduce potassium efflux and prolong the effective refractory period.

Answer] :d analysis: amiodarone has an early source effect on a variety of ion channels.

It reduced the automaticity and conductivity of sinus node and Purkinje fibers, significantly prolonged APD and ERP, and prolonged the Q-T interval and QRS complex. Master the knowledge points of "lidocaine, propranolol stupid, amiodarone, verapamil".