“When observations challenge the model, question its assumptions.”

Pump & Circuit is an educational cardiovascular simulator designed to explore physiological mechanisms and intervention responses.

Quantitative responses have not been clinically validated. Not for use in clinical diagnosis or treatment decisions.
Sinus rhythm75/min
Venous returnSystemic reservoir
Systemic venous reservoir. Geometry follows modelled unstressed capacity and volume; shading shows only this reservoir’s stressed and unstressed volume partition. Stressed
—mLUnstressed— mL
CVP—mmHg
Pulmonary circuit
mPAP —Mean LA pressure — mmHgPVR — WU
Coupled right and left heartAn anterior schematic cutaway: patient right is viewer left. The aortic arch curves toward patient left (viewer right), with its descending limb posterior. The pulmonary loop is a circulation diagram, not literal bilateral vessel anatomy. Both ventricular sizes follow their own calculated volume; blood flow follows pressure gradients. The pulmonary circuit connects RV ejection to left heart filling. RARVLALV
RV SVI— mL/m²
LV SVI— mL/m²
LVESVi — mL/m²RV EF —% · ESVi — mL/m²
Forward flowSystemic arteries
Equivalent resistance vessel. Calibre follows the model resistance to the negative one-quarter power as a schematic Poiseuille analogy, not anatomical vessel diameter.
MAP—mmHg
Arterial pressure—/—
SVR — dyn·s·cm⁻⁵
LVEF—%
LVEDVi—mL/m²
LVEDP—mmHg
Cardiac index—L/min/m²
Heart rate—/min
Ventricular loading Arrows indicate the direction of change.
LV preload —kPa
LV afterload —kPa
RV preload —kPa
RV afterload —kPa
mL/mmHg
Stiffer ← → More compliant
Arterial storage: the contour pulses with stored volume. Compliance is the separately adjustable pressure-volume slope.Arterial storageShape pulses with volume
Pulse pressure— mmHgSBP − DBP
Arterial pulse · radial estimate
AorticRadial estimate

LV pressure–volume
Starting referenceRolling averageCurrent beat
P (mmHg)LV volume index (mL/m²)0

0:00 simulated
Hemodynamic goals achieved

Pump & Circuit

INTERACTIVE CARDIOVASCULAR PHYSIOLOGY4.12.8

The circulation is complex.

Pump & Circuit uses a simplified mechanistic model to explore how pressure, flow and volume interact - and how those relationships change when things go wrong.

The model is evolving. As it should.

Created by a cardiologist.

Kaido Paapstel

Tartu University Hospital, Heart Clinic

Estonia

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