Question

What is the first-line antiarrhythmic agent given in cardiac arrest?

A) Magnesium sulfate
B) Lidocaine
C) Epinephrine
D) Amiodarone

Answer 1

The first-line antiarrhythmic agent given in cardiac arrest is C) Epinephrine, which enhances cerebral and coronary blood flow and increases heart rate and force of contraction. Amiodarone and procainamide are potassium channel blockers that affect the action potential's repolarization phase.

Step-by-step explanation:

The first-line antiarrhythmic agent given in cardiac arrest according to Advanced Cardiac Life Support (ACLS) guidelines is C) Epinephrine. Epinephrine is administered for its vasoconstrictive effects that enhance cerebral and coronary blood flow during the resuscitation period. It is also used for its ability to increase heart rate and force of contraction, aiding in the return of spontaneous circulation. While Amiodarone and Lidocaine are also antiarrhythmic agents used in the management of cardiac arrest situations, they are not the first-line treatment. Magnesium sulfate is used in specific situations such as Torsades de Pointes or hypomagnesemia-induced arrhythmias.

Potassium channel blockers like amiodarone and procainamide would affect the repolarization phase of the action potential, as this phase is primarily governed by the outflow of K+ through voltage-gated potassium channels. By blocking these channels, these drugs can alter the duration of the action potential and the refractory period, which can have therapeutic effects in cases of dysrhythmia.

Answer 2

Epinephrine is the first-line treatment in cardiac arrest to restore heart rhythm, while potassium channel blockers like amiodarone affect the repolarization phase of the action potential. AEDs are crucial devices used to correct arrhythmias in sudden cardiac arrest.

Step-by-step explanation:

The first-line antiarrhythmic agent given in cardiac arrest is Epinephrine (Answer: C). Epinephrine is administered in cases of cardiac arrest to increase coronary and cerebral blood flow during resuscitation by stimulating alpha and beta-adrenergic receptors.

Potassium channel blockers, such as amiodarone and procainamide, are used to treat cardiac dysrhythmia by impeding the movement of K+ through voltage-gated K+ channels. These drugs would affect the repolarization phase of the cardiac action potential, prolonging it and thereby slowing the heart rate.

Automated External Defibrillators (AEDs) are portable devices used to treat victims of sudden cardiac arrest. They can diagnose heart conditions and apply a shock to terminate arrhythmias allowing the natural pacemaker to restore normal heart rhythm.