Different cardiological tests are offered in this category, such as an electrocardiogram (ECG), a simple test used to check the heart's rhythm and electrical activity, a treadmill test (TMT) or cardiac stress test that helps to determine an abnormal rhythm to the heart muscles during exercise conditions and an echocardiogram, or "echo", performed with an ultrasound machine and used to look at the heart and nearby blood vessels. A Holter monitor test is also performed in this category, a small and wearable device that records the heart's rhythm and is used to detect or determine the risk of irregular heartbeats (arrhythmias).