What effect can controlled electric shocks have on fibrillation?

Controlled electric shocks, such as those delivered during defibrillation, are specifically designed to correct abnormal heart rhythms, including fibrillation. When the heart is in a state of fibrillation, it is unable to pump blood effectively, which can lead to a lack of oxygen supply to vital organs. The application of controlled electric shocks can help to reset the heart's electrical system and restore a normal rhythm.

In particular, when these shocks are administered, they can depolarize the heart muscle all at once. This can effectively interrupt the chaotic electrical activity that causes fibrillation, allowing the heart’s natural pacemaker cells to regain control. As a result, this intervention can successfully stop fibrillation and restore a proper, organized heartbeat.

The other options do not accurately describe the potential outcomes of controlled electric shocks on fibrillation. For example, stating that it worsens the condition does not reflect the clinical use of defibrillation, which aims to save lives. Similarly, increasing heart rate without addressing arrhythmias would not be a desired outcome in a clinical setting, and the assertion that it can only be fatal overlooks the critical lifesaving benefits of appropriately administered electric shocks in medical emergencies.