1 The Romans also used a 12 hour clock. 2  The 12 hour dial became popular with mechanical clocks during the 15th and 16th centuries and this has continued to this day.  The abbreviations for am and pm are often also written as a.m. and p.m. or AM and PM.
Stress Testing/Stress Echocardiogram. A stress echocardiogram is a non-invasive test that combines two tests--a treadmill stress test (TST) and an echocardiogram (ECHO). This test is used to see how the heart muscle contracts during rest and during exercise. A stress echo is made up of three parts: a resting echo study, a stress test, and a repeat echo while the heart is beating fast. (See also Drug Induced Stress Test or Nuclear Stress Test--below)
Your doctor can use the results of your stress echo test to decide whether you need treatment or additional tests to evaluate the health of your heart. What to Expect. If you are going to have a stress echo test, you will be in the cardiology office for approximately 1 1/2 hours. The stress echo test will take about 30 to 60 minutes of that time. A technician will attach electrodes to your chest and back to monitor your heart function throughout the test.