Cardio: Class IV Antiarrhythmics Flashcards

1
Q

What is the basic function of class IV antiarrhythmics?

A

They, like the class II drugs, slow heart rate. Class IV drugs do so by blocking nodal calcium channels.

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2
Q

What type of calcium channels do the class IV drugs block?

A

L-type, also called non-dihydropyridine (think of the L-shaped handle of the Non-Dairy soft-serve dispenser)

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3
Q

What are the classic class IV drugs?

A

Verapamil (Very Vanilla ice cream)Diltiazem (Delicious Dark chocolate)

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4
Q

What do calcium-channel blockers do to the cardiac action potential?

A

It slows the phase 0 upslope, thereby decreasing sinus activity, prolonging conduction velocity, and lengthening refractory period –all nodal effects.

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5
Q

True or false: class IV drugs can cause increased QT interval.

A

False. They cause increased PR interval, because they slow conduction between the atria and ventricles.

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6
Q

Which part of the heart can class IV drugs treat?

A

The atria (think of the broken bottom half of the heart sign), because class IV drugs block nodal rhythms

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7
Q

What kind of arrhythmias can class IV drugs treat?

A

Atrial fibrillation and atrial flutter (think of the TV with static in the shop) because they prolong conduction time and can prevent the atria from inducing ventricular tachycardias

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