Reference Worksheets

Single-page cath-lab and echo reference sheets. Each one works through a real case with every step shown, so the printed numbers can be checked against the printed formulas. Free to print and hand out.

These sheets exist because the equations that matter in the cath lab and the echo lab are the ones people look up under time pressure — at the table, at the machine, or the night before a board exam. Each sheet keeps the derivation visible rather than reducing it to a number: the constants are named, the units are stated at every step, and the worked example is arithmetic you can follow line by line. Where a formula has a validity domain, the sheet says so, because most of the errors these calculations produce come from applying them outside the conditions they were derived in — Gorlin in low-flow states, pressure half-time straight after balloon valvuloplasty, PISA on a crescentic secondary-MR orifice, the LaFarge oxygen-consumption estimate in an adult when it was derived in children.

Every threshold quoted is tied to a named source — the 2020 ACC/AHA valvular heart disease guideline for stenosis and regurgitation staging, the ASE recommendations for chamber quantification and for grading native valvular regurgitation, and the 2022 ESC/ERS definitions for pulmonary hypertension. Where a cut-off has moved, the sheet uses the current one and says what it replaced, so a reader who learned the older number can see why their recollection differs rather than assuming the sheet is wrong. The HTML version of each sheet is the source the PDF is generated from, so the two never drift apart.