RCCS common mistakes
RCCS · Understand the traps and how to avoid them.
Calls an atrial septal defect on a fetal four-chamber colour frame where a dropout appears at the septum primum, without confirming the foramen ovale flap in a second plane.
The fetal septum primum is thin and the beam strikes it near-perpendicular, so colour dropout mimics a defect; candidates trust a single pretty frame because that is how review images are usually shown.
What to do instead
Confirm any interatrial finding in two orthogonal planes including a subcostal/caval sagittal view showing the flap; use a low Nyquist limit (roughly 15-30 cm/s) and remember normal foramen ovale flow is right-to-left.
Diagnoses dextrocardia or abnormal situs from a single transverse chest view without first establishing fetal lie, stomach position, and the relationship of the descending aorta to the spine.
Fetal position rotates the apparent cardiac axis, and candidates anchor on the screen position of the heart rather than on internal landmarks.
What to do instead
Before commenting on axis or situs, document stomach side, aortic-spine relationship, and cardiac apex; normal axis is about 45 degrees (plus or minus 20) leftward of the midline from the spine-anterior midline.
Names the diagnosis straight from the four-chamber appearance (for example 'single ventricle' or 'TGA') instead of writing out situs, ventricular loop, atrioventricular connection, ventriculoarterial connection, and associated lesions.
Pattern recognition from memorised images is faster under time pressure, and vignettes deliberately combine unusual features that defeat image matching.
What to do instead
Force a written sequential segmental analysis for every lesion question, then derive the name from the connections; if the connections do not support the memorised label, the label is wrong.
Labels any heart with an anteriorly arising aorta as transposition, without checking which ventricle each great artery arises from and whether the atrioventricular connection is concordant.
Textbook images of d-TGA fix the anterior-aorta picture in memory, and the atrioventricular connection step is easily skipped.
What to do instead
Separate the two questions: atrioventricular concordance versus discordance, then ventriculoarterial concordance versus discordance; l-TGA requires both discordances, d-TGA requires AV concordance with VA discordance.
Reads colour aliasing in a high-velocity jet as turbulence or stenosis because the colour scale is left at a low Nyquist limit.
Default machine presets favour detecting low-flow shunts, and candidates do not re-optimise the scale when moving from shunt hunting to gradient work.
What to do instead
Set the Nyquist limit just below the expected peak velocity so the jet core is unambiguous, then interrogate the same jet with continuous-wave Doppler for the actual gradient.
Measures a peak velocity or gradient with the Doppler cursor more than about 20 degrees off the flow axis, or from a single apical window because it is convenient.
Only one window is attempted before measuring, and the angle error is invisible on the trace, so the number looks clean and gets reported unchanged.
What to do instead
Interrogate from at least two windows (apical, right parasternal, suprasternal, subcostal) and use the highest velocity obtained with the smallest angle; document the window used and do not angle-correct unless the true angle is known.
Applies the simplified Bernoulli equation (4V squared) to a stenotic or shunt jet whose proximal velocity exceeds about 1.5 m/s, and reports the resulting gradient.
The simplified form is taught first and used everywhere; the proximal velocity term is forgotten precisely in the severe lesions where it matters most.
What to do instead
Use 4(V2 squared minus V1 squared) whenever the proximal velocity is elevated, and state the proximal velocity alongside the peak gradient in the report.
Calculates Qp/Qs from a single outflow-tract diameter measured in an arbitrary phase and level, then multiplies by a velocity-time integral from a different site.
Diameter is squared, so a 1 mm error is magnified, and candidates do not appreciate how much the measurement level and cardiac phase shift the result.
What to do instead
Measure the diameter at the valve annulus in mid-systole, average three to five beats in sinus rhythm, take the velocity-time integral from the identical site and phase, and sanity-check the ratio against the colour and Doppler shunt size.
Assesses a bidirectional Glenn or Fontan pathway the way a biventricular heart is assessed, expecting systemic-level saturations and interpreting passive cavopulmonary flow as an abnormal shunt.
Training concentrates on shunt lesions, and the expected saturations and flow patterns of each palliation stage are memorised as numbers rather than as physiology.
What to do instead
Anchor expected saturations by stage (Norwood roughly 75-85%, Glenn roughly 80-85%, Fontan at or above 95%), recognise biphasic passive flow in the Fontan pathway as normal, and use a bubble study to demonstrate a right-to-left fenestration rather than calling it a shunt defect.
Images a sick neonate at high mechanical index, large sector, and long dwell time because the default preset 'gives a better picture'.
Diagnostic confidence is prioritised over dose in the moment, and neonatal thermal risk is underweighted because the patient is small and the study feels brief.
What to do instead
Apply ALARA routinely: narrow the sector and depth, use zoom and high-frequency transducers instead of deep penetration, keep the mechanical index and thermal index as low as the question allows, and limit dwell over any single region.