Focused cardiac ultrasonography is more effective than physical examination for the identification of left ventricular systolic dysfunction, with a sensitivity of 73 to 100% and a specificity of ...

A cardiac cycle lasts about 0.8 seconds, or 800 milliseconds. (A millisecond is one one-thousandth of a second.) Commotio cordis takes place within a 20- to 40-millisecond window of the cardiac cycle.

A cardiac cycle consists of two phases: systole and diastole. During systole, the heart muscles contract, and during diastole, they relax.