A multi-channel electrocardiogram display showing the 12 standard ECG leads arranged in clinical format. Each lead displays realistic P-QRS-T wave complexes on a medical-standard grid background with calibration markers. This visualization replicates the familiar layout used in hospitals and clinics worldwide, making it immediately recognizable to healthcare professionals and useful for medical education.
# anyplot.ai
# ecg-twelve-lead: ECG/EKG 12-Lead Waveform Display
# Library: makie 0.22.10 | Julia 1.11.9
# Quality: 93/100 | Created: 2026-06-17
using CairoMakie
using Colors
using Random
Random.seed!(42)
# --- Theme tokens -----------------------------------------------------------
const THEME = get(ENV, "ANYPLOT_THEME", "light")
const PAGE_BG = THEME == "light" ? colorant"#FAF8F1" : colorant"#1A1A17"
const INK = THEME == "light" ? colorant"#1A1A17" : colorant"#F0EFE8"
const INK_SOFT = THEME == "light" ? colorant"#4A4A44" : colorant"#B8B7B0"
# Imprint palette position 1 (brand green) is the ECG trace — the first series.
const TRACE = colorant"#009E73"
# Imprint matte red (#AE3030) renders the classic ECG paper grid; the theme
# background stays #FAF8F1 / #1A1A17 per the style guide.
const GRID_RED = colorant"#AE3030"
const MINOR_A = THEME == "light" ? 0.18 : 0.24
const MAJOR_A = THEME == "light" ? 0.42 : 0.50
const GRID_MINOR = RGBAf(GRID_RED.r, GRID_RED.g, GRID_RED.b, MINOR_A)
const GRID_MAJOR = RGBAf(GRID_RED.r, GRID_RED.g, GRID_RED.b, MAJOR_A)
# --- Synthetic ECG model ----------------------------------------------------
# One P-QRS-T complex as a sum of Gaussians, in mV, centred on the R peak.
gauss(t, a, mu, sig) = a * exp(-((t - mu)^2) / (2 * sig^2))
beat(t, p) =
gauss(t, p.P, -0.200, 0.025) +
gauss(t, p.Q, -0.025, 0.012) +
gauss(t, p.R, 0.000, 0.013) +
gauss(t, p.S, 0.028, 0.015) +
gauss(t, p.T, 0.180, 0.042)
# Per-lead morphology — normal sinus rhythm with standard polarities and the
# precordial R/S progression (deep S in V1/V2 → tall R in V4–V6); aVR inverted.
const LEAD_PARAMS = Dict(
"I" => (P = 0.10, Q = -0.05, R = 0.70, S = -0.12, T = 0.20),
"II" => (P = 0.15, Q = -0.05, R = 1.10, S = -0.15, T = 0.30),
"III" => (P = 0.07, Q = -0.04, R = 0.45, S = -0.10, T = 0.14),
"aVR" => (P = -0.10, Q = 0.05, R = -0.55, S = 0.10, T = -0.18),
"aVL" => (P = 0.06, Q = -0.05, R = 0.40, S = -0.08, T = 0.12),
"aVF" => (P = 0.10, Q = -0.04, R = 0.60, S = -0.12, T = 0.18),
"V1" => (P = 0.08, Q = 0.00, R = 0.25, S = -0.80, T = 0.12),
"V2" => (P = 0.10, Q = 0.00, R = 0.45, S = -1.00, T = 0.28),
"V3" => (P = 0.10, Q = -0.05, R = 0.75, S = -0.70, T = 0.32),
"V4" => (P = 0.12, Q = -0.08, R = 1.25, S = -0.35, T = 0.36),
"V5" => (P = 0.12, Q = -0.08, R = 1.10, S = -0.20, T = 0.30),
"V6" => (P = 0.10, Q = -0.06, R = 0.85, S = -0.12, T = 0.25),
)
# 1000 Hz sampling, ~75 bpm (RR = 0.80 s). Returns time (s) and voltage (mV).
function ecg_signal(duration, p; fs = 1000, rr = 0.80, first_r = 0.35)
t = collect(0:1/fs:duration)
v = zeros(length(t))
for r0 in first_r:rr:duration
v .+= beat.(t .- r0, Ref(p))
end
v .+= 0.006 .* randn(length(t)) # faint measurement noise
return t, v
end
# --- Display geometry (millimetres: 25 mm/s horizontal, 10 mm/mV vertical) ---
const MM_PER_S = 25.0
const MM_PER_MV = 10.0
const grid_layout = [
("I", "aVR", "V1", "V4"),
("II", "aVL", "V2", "V5"),
("III", "aVF", "V3", "V6"),
]
const row_centers = [124.0, 96.0, 68.0] # top → bottom
const col_starts = [14.0, 76.25, 138.5, 200.75] # 2.5 s (62.5 mm) per column
const X_MAX = 265.0
const Y_MAX = 150.0
# --- Figure -----------------------------------------------------------------
fig = Figure(resolution = (1600, 900), fontsize = 14, backgroundcolor = PAGE_BG)
ax = Axis(
fig[1, 1];
title = "ecg-twelve-lead · julia · makie · anyplot.ai",
titlesize = 26,
titlecolor = INK,
titlegap = 14,
backgroundcolor = PAGE_BG,
aspect = DataAspect(),
)
hidedecorations!(ax)
hidespines!(ax)
limits!(ax, -1, X_MAX + 1, -2, Y_MAX)
# ECG paper grid: light lines every 1 mm, bold lines every 5 mm.
vlines!(ax, collect(0:1:X_MAX); color = GRID_MINOR, linewidth = 0.4)
hlines!(ax, collect(0:1:Y_MAX); color = GRID_MINOR, linewidth = 0.4)
vlines!(ax, collect(0:5:X_MAX); color = GRID_MAJOR, linewidth = 0.9)
hlines!(ax, collect(0:5:Y_MAX); color = GRID_MAJOR, linewidth = 0.9)
# 12 leads in the standard 3×4 clinical grid, each with a 1 mV calibration pulse.
for (ri, leads) in enumerate(grid_layout)
yc = row_centers[ri]
cal_x = [3.0, 5.0, 5.0, 9.0, 9.0, 11.0]
cal_y = [yc, yc, yc + MM_PER_MV, yc + MM_PER_MV, yc, yc]
lines!(ax, cal_x, cal_y; color = TRACE, linewidth = 1.4)
for (ci, lead) in enumerate(leads)
cs = col_starts[ci]
t, v = ecg_signal(2.5, LEAD_PARAMS[lead])
lines!(ax, cs .+ t .* MM_PER_S, yc .+ v .* MM_PER_MV;
color = TRACE, linewidth = 1.2)
text!(ax, cs + 1.5, yc + 13; text = lead, color = INK,
fontsize = 21, font = :bold, align = (:left, :bottom))
end
end
# Full-length Lead II rhythm strip across the bottom (10 s = 250 mm).
yr = 28.0
cal_x = [3.0, 5.0, 5.0, 9.0, 9.0, 11.0]
lines!(ax, cal_x, [yr, yr, yr + MM_PER_MV, yr + MM_PER_MV, yr, yr];
color = TRACE, linewidth = 1.4)
t_rhythm, v_rhythm = ecg_signal(10.0, LEAD_PARAMS["II"])
lines!(ax, 14.0 .+ t_rhythm .* MM_PER_S, yr .+ v_rhythm .* MM_PER_MV;
color = TRACE, linewidth = 1.2)
text!(ax, 15.5, yr + 13; text = "II", color = INK,
fontsize = 21, font = :bold, align = (:left, :bottom))
# Scale reference.
text!(ax, X_MAX, 2; text = "25 mm/s · 10 mm/mV · 1 mV calibration",
color = INK_SOFT, fontsize = 15, align = (:right, :bottom))
# --- Save -------------------------------------------------------------------
save("plot-$(THEME).png", fig; px_per_unit = 2)
Part of ECG/EKG 12-Lead Waveform Display on anyplot.ai.