Variations in heart-block sometimes attributed to a supernormal recovery phase

Paroxysmal Ventricular Tachycardia

“…Since then a number of other cases have been described (Jervell, 1934;Luten D, & Pope, 1930;Scherf & Schott, 1939;and Kline, Conn, & Rosenbaum, 1939). Although doubt has been cast upon the interpretations of some of the tracings, it now seems to be accepted that the supernormal phase does occur at various points in the human cardiac cycle, and it may account for both A-V and V-A conduction in certain cases.…”

Sino-Auricular Block, Interference Dissociation, and Different Recovery Rates of Excitation in the Bundle Branches

“…Less commonly, interference dissociation is seen in cases of near complete A-V dissociation, with occasional sinus beats being conducted in a favourable time period, a phenomenon usually attributed to the likelihood that junctional tissues have a supernormal phase of excitation and conductivity following their refractory period. Some of the best examples of this phenomenon are the first case of Lewis and Master (1924), the cases of Wolferth (1928), of Luten and Pope (1930), of Pareja (1933), and the first case of Burchell (1942).Electrocardiographic records obtained recently from a woman, aged 60, exhibited the recurring phenomenon of nodal rhythm with interference dissociation in which the ventricular beat conducted from the auricle showed the presence of either left or right bundle branch block. The unique feature was the fact that the type of bundle branch block exhibited was determined by the time relationship between the P wave that was to be followed by a ventricular response and the preceding R wave of the idioventricular (nodal) beat.…”

“…Less commonly, interference dissociation is seen in cases of near complete A-V dissociation, with occasional sinus beats being conducted in a favourable time period, a phenomenon usually attributed to the likelihood that junctional tissues have a supernormal phase of excitation and conductivity following their refractory period. Some of the best examples of this phenomenon are the first case of Lewis and Master (1924), the cases of Wolferth (1928), of Luten and Pope (1930), of Pareja (1933), and the first case of Burchell (1942).…”