| IPI | interpulse interval |
|---|---|
| ISI | infarct size index; initial slope index; injury severity index; Institute for Scientific Information... |
| ISIH | interspike interval histogram |
| ITI | inter-alpha-trypsin inhibitor; intertrial interval |
| IWI | inferior wall infarction; interwave interval |
| sphygmic interval | The period in the cardiac cycle when the semilunar valves are open and blood is being ejected from the ventricles into the arterial system. Synonym: ejection period. (05 Mar 2000) |
|---|---|
| Sturm's interval | The distance between the anterior and posterior focal lines in a spherocylindrical lens combination. (05 Mar 2000) |
| Q-RB interval | The time between the onset of the Q wave of the QRS complex and the right bundle-branch potential (normally 15-20 msec). (05 Mar 2000) |
| Q-R interval | The time elapsing from the onset of the QRS complex to the peak of the R wave; measures the time of onset of the intrinsicoid deflection if determined in an appropriate unipolar lead tracing. (05 Mar 2000) |
| QRS interval | The duration of the QRS complex in the electrocardiogram. (05 Mar 2000) |
| Q-S2 interval | electromechanical systole |
| Q-T interval | Time from electrocardiogram Q wave to the end of the T wave corresponding to electrical systole. (05 Mar 2000) |
| interectopic interval | The distance between consecutive ectopic complexes in the electrocardiogram. (05 Mar 2000) |
| interval | The space between two objects or parts, the lapse of time between two recurrences or paroxysms. Origin: L. Vallum = rampart (18 Nov 1997) |
| interval operation | An operation performed during a period of quiescence or of intermission in the condition necessitating surgery. (05 Mar 2000) |
| interval scale | Like a temperature scale in centigrade or Fahrenheit units, a scale on which the intervals are equal but which has an arbitrary zero point; e.g., intelligence quotient values are values along an interval scale. (05 Mar 2000) |
| isovolumic interval | Time during which both an A-V and a semilunar valve are closed. (05 Mar 2000) |
| escape interval | The time between the last beat of the patient's basic rhythm (ectopic or sinus beat) and a beat from a spontaneous escape focus or the initial electronic pacemaker impulse (a preset interval in the circuitry); it may be either a shorter or a longer time period than the pulse interval. (05 Mar 2000) |
| focal interval | The distance between the anterior and posterior focal points of the eye. (05 Mar 2000) |
| lucid interval | In psychoses or delirium, a rational period appearing in the course of the mental disorder. (05 Mar 2000) |