Which medication is not typically used to manage cardiac arrhythmias and can lengthen QTc?

The correct answer identifies calcium channel blockers as a medication that is not typically used to manage cardiac arrhythmias and can also lengthen the QTc interval. While calcium channel blockers are valuable in treating various cardiovascular conditions, they are not the first-line treatment for most types of arrhythmias. Instead, they are primarily used for managing hypertension, angina, and certain cases of tachyarrhythmias but with limited efficacy in controlling arrhythmias compared to other medication classes.

In addition to their primary uses, some calcium channel blockers can have effects on the heart's electrical conduction system, which may contribute to a prolonged QTc interval, potentially increasing the risk of life-threatening ventricular arrhythmias like Torsades de Pointes.

In contrast, beta-blockers are widely recognized and commonly used to manage a range of cardiac arrhythmias by slowing heart rate and stabilizing electrical conduction. Antipsychotics and certain antidepressants, particularly some of the tricyclic antidepressants, may also be known to cause QTc prolongation but are sometimes applied in specific scenarios involving arrhythmias, especially when considering the underlying psychological conditions that can contribute to cardiac instability. Thus, the emphasis is on the distinctive roles of calcium channel blockers compared to these other classes