Aktionspotential und Mechanogramm bei experimenteller Druckhypertrophie

Gülch, R. W.; Baumann, R; Jacob, R.

doi:10.1007/978-3-642-72339-1_48

Cited by 2 publications

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“…It is very likely that the significant increase in the time to peak force of the hypertrophied myocardium is due to the prolongation of the myocardial action potential (8,14). As shown by investigations of Antoni (2), an action potential prolongation directly causes a prolonged activation which results in a prolonged mechanical time to peak force and increased peak force.…”

Section: Discussionmentioning

confidence: 99%

Analysis of myocardial action potential in left ventricular hypertrophy of Goldblatt rats

1979

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Action potentials were measured in hypertropl~ied rat myocardium by means of glass microelectrodes. Left ventricular hypertrophy was induced by experimental chronic coarctation of one renal artery without contralateral nephrectomy. The action potentials of the hypertrophied myocardium exhibit a marked prolongation without any significant changes in the transmembrane resting potential, in the amplitude, or in the maximum upstroke velocity of the action potential. The increase in the half-width of the action potential for the 6-week stage after the surgical procedure is 235%, for the 12-week stage 281%, and for the 24-week stage 314%. The prolongation of the action potentials was more marked when the degree of hypertrophy was more severe.After depression of the fast Na + inward current either by tetrodotoxin, by augmentation of the extracellular K + concentration, or by reduction of the extracellular Na + concentration, action potentials with similar marked broadening were still obtained in hypertrophied myocardium. The results under variation of the extracellular Ca ++ concentration and simultaneous inactivation of the fast Na* channels suggest that the slow transmembrane inward current is primarily carried by Ca ++ ions.The prolongation of the action potentials could be one cause of the significant increase in the time to peak force as well as the augmentation of isometric force found in this model of hypertrophied myocardium.In contrast to numerous available mechanical, biochemical and mor. phological data, few studies on electrical properties of hypertrophied cardiac muscle have been published: Most studies are concerned with electrocardiographic alterations under cardiac hypertrophy and correlate changes in ECG with changes in geometry of the hypertrophied heart without regard for possible alterations in the transmembrane electrical activity of the hypertrophied cardiac cell.

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Section: Discussionmentioning

confidence: 99%

Analysis of myocardial action potential in left ventricular hypertrophy of Goldblatt rats

1979

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Alterations in rat myocardial mechanics under Goldblatt hypertension and experimental aortic stenosis

Kämmereit

Jacob

1979

Basic Res Cardiol

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Left ventricular hypertrophy was induced in young male Wistar rats by unilateral renal artery constriction, either with (Goldblatt I [ = G I]) or without (Goldblatt II [ = G II]) simultaneous contralateral nephrectomy. An average increase in left ventricular weight of 55% and 18% respectively was reached within 4 weeks as compared with controls of the same age. Further increase in ventricular mass up to the 6-month stage was considerably dependent on the degree of inhibition of body growth of the experimental animals. Other rats underwent a stenosis of the Aorta ascendens (AO) with a reduction in diameter to 50%--60% of the original value, whereby a left ventricular hypertrophy of 10%--30% ensued. Isolated trabecular muscle strips of the left ventricle were examined 4, 8 and 24 weeks (G II), 4 and 8 weeks (G I), and 4 and 6 weeks (AO) after operation. Sham operations were performed for all models used.

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Aktionspotential und Mechanogramm bei experimenteller Druckhypertrophie

Cited by 2 publications

References 0 publications

Analysis of myocardial action potential in left ventricular hypertrophy of Goldblatt rats

Analysis of myocardial action potential in left ventricular hypertrophy of Goldblatt rats

Alterations in rat myocardial mechanics under Goldblatt hypertension and experimental aortic stenosis

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