Friable heart tissue is seen in early days after a heart attack till the scar formation is complete. This region is prone for rupture which can be fatal.
Most silent heart attacks are detected by an ECG. In Framingham Heart Study, 25 percent of the heart attacks were silent, being detected by routine ECG.
Cardiac monitors are devices with displays to show ECG, heart rate etc on a continuous basis, usually used in the intensive care unit or operation theatre.