Table 1 Storage requirements

Electrodes

10

32-213

Bipolar leads

3

0

Unipolar leads

9

32-213

*All unipolar, each electrode has an associated unipolar lead.

Electrode positions

Standardized.

Non-standardized

*Range of different layouts.

Calculated leads

Standard calculations for generating limb leads aVF, aVL, aVR and III.

Non standardized

* Range of limited lead sets, for example the Lux-32 layout expands to Lux-192 using coefficients.

Data

Usually a 10 second recording.

No set recording time. Some BSPMs store single beats.

Formatting requirements

Requires a strict standard format since the 12-lead ECG is well standardized.

Requires a versatile format to support a range of electrode layouts.

Display

12 waveforms are usually rendered onto formatted graph paper, i.e. "3 × 4 + 1".

No standard representation exists. Can be displayed as a series of scalar traces or as a contour map.

* Electrode positions must be known to generate a contour map.

Diagnostic criteria

Diagnostic criteria have been well defined.

Very little diagnostic criteria exist.

Accessibility and cost of equipment

Very accessible within the healthcare industry and relatively inexpensive.

Not all hospitals have a BSPM recording and visualisation system. Equipment can be expensive and hard to get.