SE-3B Digital 3-Channel ECG Machine

The SE-3B is a digital three-channel ECG machine with the main unit and a 7-inch colour LCD built into one body. It measures 285 mm x 200 mm x 50 mm and weighs about 2.2 kg, so it sits on a consulting-room desk and can also be carried to a ward or a screening site.

The machine acquires twelve leads simultaneously, in the standard or in the Cabrera configuration, and shows the result on screen while the built-in thermal printer records it in three channels. At the acquisition end the main figures are a sampling rate of 8000 Hz (1 ms), a frequency response of 0.05-150.0 Hz, a time constant of at least 3.2 s, a common-mode rejection ratio above 100 dB, a noise level of no more than 15 microvolt peak-to-peak, a polarisation tolerance of plus or minus 600 mV and a sensitivity threshold of 20 microvolt.

Filtering is split three ways: AC 50 Hz at -20 dB, EMG 35-45 Hz at -3 dB and drift 0.5 Hz at -3 dB, which address mains interference, muscle artefact and baseline drift respectively. Sensitivity is selectable across six steps of 1.25, 2.5, 5, 10, 20 and 40 mm/mV within plus or minus 2 percent, and paper speed across six steps of 5, 6.25, 10, 12.5, 25 and 50 mm/s within plus or minus 3 percent, so a department can keep its customary settings.

Recording uses a hot-dot array at 8 dots/mm vertically and 40 dots/mm horizontally at 25 mm/s, on 80 mm or 50 mm wide high-speed thermal roll paper 20 m long. Each electrode has its own contact-failure indicator, which makes a loose lead easy to find before acquisition rather than after.

The delivered set is the main unit, one patient cable, four limb electrode clamps, six chest electrode bulbs, a ground lead, a power cord, an operation manual, one roll of thermal paper, a certificate of conformity and a warranty card. Cardiology, emergency, intensive care, primary care and screening departments all use it.