Main-Stem Extrasystoles

Mainstem extrasystoles.

Extrasystoles arising in the main stem of the bundle of His are generally regarded as very rare; only 7 examples have been published since their original description by Lewis in 1911 and 2 of these fail to satisfy rigid criteria for diagnosis. Four further examples, encountered in a relatively small series of tracings, are here presented and it is concluded that such extrasystoles are not so mu...

Retrograde conduction of ventricular extrasystoles with consideration of return extrasystoles.

Extrasystoles and Allied Arralythmias

Concealed ventricular extrasystoles.

AN apparently haphazard distribution of ventricular extrasystoles may not be so haphazard as it appears and indeed may mask an underlying regularity. We previously reported a case in which careful analysis uncovered a simple but remarkable phenomenon, namely, that the interectopic intervals always contained an odd number of sinus beats.1 This was explicable on the assumption that a bigeminal rh...

Reciprocal ventricular extrasystoles.

An impulse originating in the A-V node or ventricles may be conducted retrogradely through the A-V node. The retrograde impulse may, under certain circumstances, return anterogradely through the A-V node to the ventricles giving rise to a reciprocal or return extrasystole. One explanation for this re-entry phenomenon is based on the concept of a functional vertical division or longitudinal diss...