Comparative force-frequency relationships in human and other mammalian ventricular myocardium
| Autor: | N. M. Buckley, R. S. Litwak, Z. J. Penefsky |
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| Rok vydání: | 1972 |
| Předmět: |
Adult
medicine.medical_specialty Contraction (grammar) Physiology Biopsy Guinea Pigs Clinical Biochemistry Action Potentials Stimulation In Vitro Techniques Myosins Human myocardium Models Biological Guinea pig Ventricular myocardium Adenosine Triphosphate Physiology (medical) Internal medicine Methods medicine Ventricular muscle Animals Humans Contraction velocity Force frequency Aged Electromyography Chemistry Myocardium Sodium Heart Middle Aged Papillary Muscles Actins Electric Stimulation Rats Ion Exchange Endocrinology Potassium Biophysics Calcium Factor Analysis Statistical Muscle Contraction |
| Zdroj: | Pfl�gers Archiv European Journal of Physiology. 332:259-270 |
| ISSN: | 1432-2013 0031-6768 |
| DOI: | 10.1007/bf00588574 |
| Popis: | Contractile responses to increased stimulation frequency were analyzed in isolated papillary and ventricular muscle bundles from human, guinea pig and rat hearts. Contractile tension and velocity of tension development and release were recorded while changes in frequency were made. The following were calculated for each frequency; duration of the phases of accelerating (I) and decelerating (II) contraction, and accelerating (III) and decelerating (IV) relaxation; tension at end of phases I, II and III; and instantaneous velocities at the midpoint of phase I, and at the end of phases I and III. Increasing frequency was accompanied by decreased contractile tension and velocities to a limit in rat and markedly hypertrophied adult human myocardium; but by increased contractile tension and velocities to a limit in guinea pig, late fetal human, and minimally hypertrophied adult human myocardium. The observations support the hypothesis that peak contractile tension development depends on phase I velocity and phase II duration. |
| Databáze: | OpenAIRE |
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