This is an orientation to the shapes and what they mean — not a substitute for your training or your facility's protocols. Normal pressure ranges vary slightly by source; the values here are typical adult resting figures for learning.
The mental model
A catheter with a pressure transducer travels from the veins through the right heart, across to the lungs, and (for left-heart cases) into the left ventricle and aorta. Each chamber produces a characteristic pressure shape. Learn the shapes in order, and you can tell where the catheter is by the waveform alone — that's the whole game.
The six waveforms
01 Right atrium (RA)
Normal: 2–6 mmHg (mean)A low-pressure, gentle waveform with small undulations — the classic a, c, and v waves. It's the first pressure you see as the catheter enters the right heart.
- a wave — atrial contraction
- c wave — tricuspid valve bulging back during early ventricular contraction
- v wave — atrial filling against a closed tricuspid valve
02 Right ventricle (RV)
Normal: ~15–30 / 2–8 mmHgA dramatic change: a tall systolic spike with a low diastolic pressure that dips near zero. The sharp rise and low dip is the RV signature. Recognizing the jump from RA to RV is your first key transition.
03 Pulmonary artery (PA)
Normal: ~15–30 / 8–15 mmHgSimilar systolic height to the RV, but the diastole is elevated, not near-zero — and you'll see a dicrotic notch as the pulmonic valve closes. The rise in diastolic pressure is how you know you crossed from RV into the PA. This is the RV→PA transition, one of the two you must recognize instantly.
04 Pulmonary capillary wedge (PCWP)
Normal: ~4–12 mmHg (mean)When the balloon-tipped catheter wedges into a small pulmonary artery branch, the waveform goes low and gentle again — it looks much like the RA tracing, with a and v waves. The wedge pressure is a downstream estimate of left atrial pressure, which makes it a window into the left heart from the right side.
05 Left ventricle (LV)
Normal: ~90–140 / 5–12 mmHgShape resembles the RV — tall systolic spike, low diastole — but at much higher pressure. The systolic peak is roughly five to six times the RV's. A low diastole here is normal; an elevated LV end-diastolic pressure is one of the meaningful findings techs learn to flag.
06 Aorta (AO)
Normal: ~90–140 / 60–90 mmHgSame systolic height as the LV, but the diastole is high — the aorta stays pressurized between beats — and there's a clear dicrotic notch from aortic valve closure. Crossing from LV to aorta, systole stays put while diastole jumps up. This is the LV→AO transition, the second one you must know cold.
The two transitions that carry everything
If you internalize nothing else, internalize these:
RV → PA
Systole stays about the same; diastole rises and a dicrotic notch appears. You've crossed the pulmonic valve.
LV → AO
Systole stays about the same; diastole rises and a dicrotic notch appears. You've crossed the aortic valve.
Notice they're the same idea on opposite sides of the heart: crossing a semilunar valve from a ventricle into a great artery, systole holds while diastole climbs. See that pattern and you'll never be lost about where the catheter is.
Waveforms make sense in motion.
The rhythm simulator and the free Cath Lab Field Guide put these pressures and shapes in front of you to practice with.
How to actually learn these
- Learn them in catheter order — RA → RV → PA → wedge, then LV → aorta. The sequence is the memory aid.
- Anchor each shape to a location. Don't memorize squiggles; picture where the transducer sits.
- Master the two transitions first. They're the highest-yield thing on this page, for the room and for the RCIS.
- A little every day. Hemodynamics is the one topic you cannot cram — build it in small, daily reps.
Educational content only. Waveform illustrations are schematic. Normal ranges vary by reference and patient; always defer to your training, your facility's protocols, and clinical context.