Overview
Catheter progression switches the pressure signal from RA to RV to PA to wedge along one shared pressure scale. The half-day teaching figure presents two cycles in each location as a continuous push-forward demonstration; its channel transitions are educational, not a catheter motion/position solver.
LV pullback samples LV, LVOT and aorta to distinguish a subvalvular dynamic gradient from a fixed valvular gradient. PA/RV samples pulmonary artery followed by right ventricle during catheter withdrawal. Switching studies changes the sampled location, not the selected circulation.
PA to RV withdrawal
The right-heart recording uses the same PA and RV pressure functions as the monitors, on one common scale. Rhythm, respiration, ventilation, interventions and catheter-recording artifacts remain active. The location transition is a display demonstration; it does not solve catheter motion or procedural complications.
Pulmonic stenosis raises RV systolic pressure above PA systolic pressure. Pulmonary hypertension or acute pulmonary embolism can raise RV and PA pressures together without creating valvular stenosis. Reduced flow can make an obstructive gradient smaller. The PA closure notch and diastolic runoff give way to the ventricular relaxation and filling contour; RVEDP is distinct from the RV diastolic minimum.
Pulmonic regurgitation accelerates PA diastolic runoff and can narrow the PA–RV diastolic difference. Pulmonary vascular load or RV diastolic dysfunction changes that relationship; complete pressure equalization is not required. Mixed valve disease and external constraint retain the current shared scenario.
Interpreting a sequential study
PA and RV segments occur on different beats. Respiration, irregular R–R intervals or changed loading can alter their apparent peak difference even without valve obstruction. The displayed RV−PA systolic difference is the underlying reference peak-to-peak difference, not a measurement of the sequential recording, a simultaneous instantaneous gradient or a Doppler severity grade. The common-scale overlay can display both pressure signals together.
This two-location study does not localize separate infundibular, valvular or branch-PA lesions. It does not provide pulmonary valve area, intervention thresholds or a patient-specific diagnostic result.
Post-PVC response
The isolated provocation uses a baseline beat, a premature beat at 0.65 baseline cycles, a compensatory pause and a potentiated beat at cycle 2. The premature beat has reduced pressure/flow; the post-PVC LV peak rises.
Fixed AS increases the subsequent arterial pulse in this chosen example; HOCM can reduce arterial pulse pressure despite a larger LV pressure, illustrating the Brockenbrough–Braunwald–Morrow response. Mixed fixed/dynamic obstruction blends the response rather than switching HOCM off. This is a constructed provocation, not a measured post-extrasystolic contractility test.
Carabello demonstration
The optional severe-AS example adds a simultaneous femoral trace. While the catheter crosses the critically narrowed valve, an added obstruction reduces peripheral systolic pressure; withdrawal restores it. Transit delay and peripheral amplification are separate from the LV–aortic gradient.
The imposed obstruction is bounded and only available for the severe-AS/native-flow context. It illustrates the measurement pitfall; it does not estimate catheter size, actual valve area, embolic risk or procedural suitability.
Restriction and constriction comparison
The paused comparison uses simultaneous LV/RV and atrial signals plus respiratory context. It reports LVEDP–RVEDP, RVEDP/RVSP, PASP, rapid-filling pressure change and respiratory atrial/ventricular relationships. These criteria are complementary teaching clues, not individually diagnostic.
End-diastolic equalization and a dip-and-plateau can overlap. Respiratory discordance/interdependence versus concordance is more informative in the intended comparison. Ventilation, a large atrial communication and mixed disease can change the pattern, so interpretation must retain those assumptions.
References & further reading
