Interpolation in Alternate Cycles

Report:

Sinus rhythm 51/min

VEBs, interpolated in alternate cycles

Trigeminy

Non-specific ST/T changes

Comment:

The VEBs are typical, with nonsense axis and qR morphology in V1; their concealed retrograde conduction114, prolonging the PR intervals of the post-VEB sinus beats, also attests to their ventricular ectopic provenance.

This pattern is relatively common, being, as it were, a variant of bigeminy. If alternate P waves were completely blocked (rather than just having their PR intervals increased) this would become obvious bigeminy.

A more orthodox trigeminy, from the same source, was present in the patient’s preoperative ECG (Fig 128a).

Retrograde concealed conduction and block in the same trace (but from a different patient) are shown in 128b.

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