How does an internal cardiac pacemaker differ from an automated implanted cardioverter/defibrillator?

An internal cardiac pacemaker is specifically designed to regulate heart rhythm by ensuring that the heart rate does not drop below a predetermined level. This is particularly important in patients who have bradycardia, a condition characterized by a slow heart rate. The pacemaker sends electrical impulses to the heart muscle, prompting it to contract and maintain an adequate heart rate, thus handling situations where the heart's natural pacemaker fails.

In contrast, an automated implanted cardioverter/defibrillator (AICD) primarily functions to detect and treat life-threatening arrhythmias, such as ventricular tachycardia or ventricular fibrillation. Unlike a pacemaker, which continuously manages heart rate, the AICD intervenes only during episodes of abnormal heart rhythms, delivering shock therapy to restore a normal heart rhythm.

Therefore, the distinguishing feature of the pacemaker lies in its active regulation of heart rate, making the correct choice clearly focused on its ability to provide consistent pacing when the heart rate drops below a set threshold. While the AICD has a life-saving role in detecting and correcting arrhythmias, it does not maintain a steady heart rate in the same manner as a pacemaker does.