Daily Archive 11.12.2018

The time of occurrence of ventricular extrasystoles

The time of occurrence of ventricular extrasystoles

Ventricular ectopic complexes, which occur very early in the cardiac cycle, may be superimposed on the T wave of the previous contraction and are referred to as extrasystoles “R on T”. Most episodes of ventricular fibrillation (VF) and many episodes of ventricular tachycardia (VT) are initiated by extrasystoles “R on T”, although this does not mean that extrasystoles “R on T” always cause these forms of arrhythmia.

Ventricular extrasystoles occurring in the cardiac cycle only slightly prematurely, may accidentally occur immediately after the P wave caused by the normal activity of the sinus node: the P wave, thus, unlike the atrial extrasystoles, will not be premature. Such ventricular extrasystoles are called end-dia-table.

Usually, there is a pause after the ventricular extrasystoles. When such a pause is absent and the extrasystole, thus, looks “sandwiched” between two normal complexes, the extrasystole is called interpolated.

Frequency of ventricular extrasystoles

When extrasystoles are followed after each sinus complex, the term “bigeminy” is used. If extrasystoles follow after a couple of normal complexes, this is “trigeminia.” When two ectopic complexes follow in succession, they are referred to by the term “pair beats,” or “couplet.” “Zalpom” refers to more than two consecutive ectopic complexes.