In this situation, the
auriculo-ventricular and intra-ventricular conduction are delayed,
extending the PR interval and the QRS complex thus becoming
wider. (Fig.1 and 2). Progressive increases of potassium (from
7.5 mEq/l) make the auricular muscle unresponsive to a greater
or lesser extent, possibly producing varying degrees of blockage
in the sino-auricular or in other levels and perhaps even asistole.
It is also possible to find alterations in the conduction (14) and
ectopic rates, which is sometimes difficult to interpret and among
which we find ventricular tachycardia or pseudo-tachycardia, a
complicated and difficult diagnosis (15).