Decremental Conduction in the Human Heart.

Abstract

Decremental conduction appears to have been demonstrated in the compressed or otherwise depressed mammalian auricular muscle (Drury 1 ; Drury and Andrus 2 ). This interpretation has been quite generally, but not universally accepted. No human electrocardiograms suggesting the condition have been described so far as we are aware. We have had 2 cases in which the condition is suggested. One case of interference dissociation showed a most unusual phenomenon. There were a large number of auricular impulses which penetrated to the ventricular pacemaker and disturbed its rhythm. Of these nearly 50% were blocked between that point and the ventricle proper. This observation, which appears to be unique, together with further evidence from another case with auricular premature beats, strongly suggests the presence of decremental conduction in the human heart. Even if the tracing be interpreted as one of simple reciprocating rhythm, yet the extreme peculiarity in question remains, namely a descending impulse discharging the ventricular pacemaker yet failing to reach the ventricular musculature.