HR: Heart Rate.

LVOT: Left Ventricular Outflow Tract.

diam: Diameter

PLAX: Parasternal Long Axis.

VTI: Velocity-Time Integral

A4C: Apical 4 Chambers.

RVOT: Right Ventricular Outflow Tract.

PSAX: Parasternal Short Axis.

SV: Systolic Volumen.

Q or QS: Systemic Cardiac Output.

BSA: Body Surface Area.

CI: Cardiac Index.

QP: Pulmonary Cardiac Output.

Electrocardiography

HR = 1500 / small squares number between R waves

QTc(Bazett) = QT / √RR

QTc(Fridericia) = 8.22 * ³√RR

Echocardiography

LVOT area = π (LVOT diameter/2)²

Systemic SV = LVOT area x LVOT VTI

QS = HR x Systemic SV

BSA (Mosteller) = √(W * H) / 60

CI = QS * BSA

QP = HR x SVp (SVp = RVOT area x RVOT VTI)

or (π (RVOT diameter/2)² x RVOT VTI)

QP/QS Ratio = QP/QS