Further Studies on the Physiology of Heart-Block in Mammals

Erlanger, Joseph; Hirschfelder, Arthur D.

doi:10.1152/ajplegacy.1906.15.2.153

Cited by 51 publications

(12 citation statements)

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“…In all but two of the experiments, the conduction time was distinctly increased, and in four the conduction defect was sufficient to cause the dropping out of numerous ventricular beats. Erlanger and Hirschfelder (1905) and Lewis and 2,32 Oppenheimer have shown that an increase in rate exaggerates depression of conduction, which in these experiments was becoming apparent in the period of primary fall.…”

Section: Methodsmentioning

confidence: 60%

The Action of Pituitary Extract on the Heart of the Unanesthetized Dog

Resnik¹,

Geiling²

1925

J. Clin. Invest.

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Section: Methodsmentioning

confidence: 60%

The Action of Pituitary Extract on the Heart of the Unanesthetized Dog

Resnik¹,

Geiling²

1925

J. Clin. Invest.

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“…Lengthening (1-6), shortening (2,3,5,8,9,12,16,24), and lack of alteration (13,14) of the ventricular returning cycle after ventricular extrasystoles have all been reported. Furthermore, occasional examples of shortening of the Purkinje returning cycle can be found scattered in the literature (25)(26)(27).…”

Section: Relevance To the Heart In Situmentioning

confidence: 99%

Effect of Extrasystoles on Idioventricular Rhythm

Klein

Cranefield

Hoffman

1972

Circulation Research

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Ventricular extrasystoles exert a variable effect on idioventricular rhythm. The postextrasystolic, or the "returning," cycle may be unchanged, or it may be shorter or longer than the dominant cycle. The factors responsible for these different responses have never been investigated. Therefore, the effect of electrically induced extrasystoles was studied by microelectrode techniques in an in vitro model of idioventricular rhythm consisting of spontaneously firing Purkinje fiber bundles with their attached ventricular segments. Late extrasystoles lengthened the Purkinje returning cycle, primarily by transiently increasing the duration of spontaneous phase-4 depolarization. In contrast, early extrasystoles produced shortening of the returning cycle, primarily because of the marked abbreviation of the duration of the extrasystolic action potential. Other factors affecting the ultimate duration of the Purkinje returning cycle were delineated. The effect of extrasystoles on the electrical activity of the ventricular segments was studied by surface electrograms. This effect was complex and was modified by the direction of propagation of the extrasystole with respect to the pacemaker site and by the degree of conduction delay. Ventricular electrical activity usually reflected the electrical events occurring in the pacemaker cells, but frequent exceptions occurred: the ventricular returning cycle could be prolonged while the corresponding Purkinje returning cycle was shortened and vice versa. "Interpolation" of an extrasystole did not necessarily indicate failure of the extrasystole to discharge the pacemaker site. The effects of extrasystoles on idioventricular rhythm which have been described in the earlier literature are easily understood from the findings of this study. KEY WORDS electrocardiogram premature ventricular contraction cardiac electrogramHis-Purkinje system complete heart block transmembrane potentials spontaneous phase-4 depolarization postextrasystolic cycle pacemaker cells returning cycle• Relatively little information exists in the literature concerning the effect of ventricular extrasystoles on idioventricular rhythm in

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“…Moreover, it was conceivable that if one increased the rate of the heart during anoxemia, one might bring out a change which was latent in the naturally beating heart. Erlanger and Hirschfelder (1905) and Lewis and Oppenheimer (1910-11) have shown that when auriculo-ventricular conduction was already impaired, an increase in the heart rate exaggerated the degree of block between the auricles and ventricles.…”

Section: Introductionmentioning

confidence: 99%

Observations on the Effect of Anoxemia on the Heart

Resnik¹

1925

J. Clin. Invest.

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Further Studies on the Physiology of Heart-Block in Mammals

Cited by 51 publications

References 0 publications

The Action of Pituitary Extract on the Heart of the Unanesthetized Dog

The Action of Pituitary Extract on the Heart of the Unanesthetized Dog

Effect of Extrasystoles on Idioventricular Rhythm

Observations on the Effect of Anoxemia on the Heart

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