Verapamil blocks which ion channels to affect cardiac conduction?

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Multiple Choice

Verapamil blocks which ion channels to affect cardiac conduction?

Calcium channels are what Verapamil targets. It blocks voltage-gated L-type calcium channels, which are crucial for depolarization in the heart’s nodal tissue (SA and AV nodes) and contribute to the plateau phase of the cardiac action potential. When these calcium channels are inhibited, calcium influx decreases, slowing the rate of depolarization in the nodal cells and reducing conduction through the AV node. This slows heart rate and can help terminate or prevent certain supraventricular tachycardias. In contrast, sodium channels drive the rapid upstroke of the action potential in atrial and ventricular muscle, potassium channels govern repolarization, and chloride channels play little role in conduction, so they are not the targets here.

Calcium channels are what Verapamil targets. It blocks voltage-gated L-type calcium channels, which are crucial for depolarization in the heart’s nodal tissue (SA and AV nodes) and contribute to the plateau phase of the cardiac action potential. When these calcium channels are inhibited, calcium influx decreases, slowing the rate of depolarization in the nodal cells and reducing conduction through the AV node. This slows heart rate and can help terminate or prevent certain supraventricular tachycardias. In contrast, sodium channels drive the rapid upstroke of the action potential in atrial and ventricular muscle, potassium channels govern repolarization, and chloride channels play little role in conduction, so they are not the targets here.

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