What technique is used to assess the heart's electrical activity in real-time?

The technique that is used to assess the heart's electrical activity in real-time is continuous telemetry monitoring. This method involves placing electrodes on the patient's skin, which detect electrical impulses generated by the heart. These impulses are transmitted continuously to a monitoring system, allowing healthcare providers to observe the heart's rhythm and detect any abnormalities or changes as they occur. This real-time monitoring is critical in managing patients with cardiac conditions, as it enables immediate response to dysrhythmias or other electrical disturbances of the heart.

In contrast, cardiac MRI and chest X-ray are imaging techniques that provide visual representations of heart structure and function but do not measure electrical activity. Cardiac catheterization is an invasive procedure primarily used to diagnose and treat certain heart conditions through the direct measurement of pressures and blood flow within the heart's chambers and vessels, rather than assessing electrical activity.