Unlabeled

One heartbeat of a healthy adult, lead II of a 12-lead electrocardiogram

The small bump is the upper chambers' signal; the 1.23 mV spike is the lower chambers firing, the hump after it their recovery. Over the whole recording the heart averaged 65 beats a minute.

What does this axis measure?
What does this axis measure?
One heartbeat of a healthy adult, lead II of a 12-lead electrocardiogram: 40 points, a line chart.
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y ↑
Voltage (millivolts)
x →
Elapsed time (milliseconds)
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The data: 40 points
Elapsed time (milliseconds)Voltage (millivolts)
0−0.051
8−0.07
38−0.025
60−0.006
860.045
1060.03
1100.031
138−0.065
156−0.08
194−0.064
214−0.099
228−0.17
2501.228
270−0.313
272−0.342
288−0.115
304−0.058
336−0.029
348−0.025
374−0.004
4020.009
4280.03
4320.063
4660.162
4940.285
5160.26
5320.185
5560.043
572−0.013
588−0.045
608−0.055
638−0.04
662−0.034
670−0.04
710−0.04
724−0.034
734−0.035
776−0.035
780−0.044
800−0.036
Source
PTB-XL electrocardiography dataset, version 1.0.3 (Wagner et al., Physikalisch-Technische Bundesanstalt), via PhysioNet; record 151, lead II, one beat
Licence
CC-BY 4.0 (one beat of lead II selected, ADC counts converted to mV, 401 samples thinned to 40 by Unlabeled)
Read
2026-10-23
Drawn
40 points as the puzzle showed them · line
  • Ran in puzzle #30 on October 26, 2026. Play it