Which of the following tests takes place over several weeks?

An electrocardiograph (ECG or EKG) is a test that records the electrical activity of the heart for a brief duration, usually just a few minutes. It provides a snapshot of heart activity at a single point in time and is not intended for long-term monitoring, making it unsuitable for identifying infrequent or episodic heart problems.

A Holter monitor is a portable device that continuously records the heart's rhythms for 24 to 48 hours, providing a more extended view than an ECG but still limited to a couple of days. While it offers better insight into daily heart activity than a standard ECG, it does not extend to several weeks of monitoring like an event recorder does.

A nuclear stress test evaluates the heart's function and blood flow during exercise or rest, using radioactive material to create images of the heart. Typically conducted within a single day, this test does not involve prolonged monitoring, as it aims to assess heart performance in a controlled environment rather than over an extended period.