In the V4 (shark out of water) strip, how many boxes indicate ST segment elevation?

In the context of EKG interpretation, specifically when analyzing a V4 lead reading for ST segment elevation, the measurement is generally assessed in millimeter (mm) vertical boxes or divisions on the EKG tracing. Each small box typically represents 1 mm, and the elevation is determined by comparing the ST segment to the baseline level of the P-R segment or the isoelectric line.

An elevation of 1 mm or more above the baseline is clinically significant, especially in acute settings such as the diagnosis of ST-Elevation Myocardial Infarction (STEMI). If a V4 lead strip shows 9 boxes of elevation in the ST segment, this translates to a 9 mm elevation above the baseline, which is clinically significant and indicates a potential pathology that requires immediate attention.

This level of elevation can be indicative of myocardial injury and warrants further evaluation and intervention. Therefore, when identifying the degree of ST segment elevation in the V4 lead, recognizing 9 boxes as the measurement is crucial for accurate diagnosis and treatment planning.