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  • Articles: DFG German National Licenses  (5)
  • Coronary Blood Flow  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Die extravasale Komponente des Coronarwiderstandes mit steigendem linksventrikulären Druck (1972)
    Springer
    Pflügers Archiv 333 (1972), S. 352-361 
    Details
    ISSN: 1432-2013
    Keywords: Extravascular Resistance ; Extravascular Support ; Intraventricular Pressure ; Coronary Blood Flow ; Systolic Time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In experiments on anaesthetized dogs the arterial blood pressure and the left ventricular pressure were enhanced by intraarterial blood transfusion. The circumflex branch of the left coronary artery was perfused by constant blood pressure at 65, 100 or 200 mm Hg. After elimination of the sinus node the heart rate was kept constant at 150 beats per minute by electrical stimulation of the right auricle. The metabolically regulated component of coronary resistance of the circumflex branch was kept constant by a maximal pharmacological dilatation. On this condition the coronary blood flow decreases with increasing left intraventricular systolic pressure. The coronary resistance increases. The increasing coronary resistance with increasing intraventricular blood pressure is caused by an enhancement of the extravascular component because the perfusion pressure and hematocrit were constant, and the coronary vessel maximal dilated. The rise of coronary resistance with increasing intraventricular blood pressure depends on the height of perfusion pressure. Low perfusion pressure is combined with a marked increase, while the increase is small in the experiments with high perfusion pressure. The pathophysiological significance of the results has been discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586214
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Herzfrequenz und extravasale Komponente des Coronarwiderstandes (1971)
    Springer
    Pflügers Archiv 323 (1971), S. 241-249 
    Details
    ISSN: 1432-2013
    Keywords: Coronary Blood Flow ; Extravascular Resistance ; Heart Rate ; Systolic Time ; Coronardurchblutung ; extravasaler Widerstand ; Herzfrequenz ; Systolenzeit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei elektrischer Reizung des Herzens (rechtes Herzohr) nach Ausschaltung des Sinusknotens finden sich in dem untersuchten Frequenzbereich von 60–220 Schlägen in der Minute normale Systolen- und Diastolenzeiten. Wird durch eine maximale pharmakologische Coronardilatation die intravasale Komponente des Coronarwiderstandes konstant gehalten, so läßt sich mit steigender Frequenz in allen Experimenten eine Zunahme der extravasalen Komponente des Coronarwiderstandes nachweisen. Diese Zunahme wird durch die relative Zunahme der Systolenzeit auf Kosten der Diastolenzeit hervorgerufen. Die Zunahme der extravasalen Komponente der Coronarwiderstandes ist relativ gering, weil eine Abnahme des systolischen Einstromwiderstandes die Wirkung der Systolenverlängerung vermindert. Die extravasale Komponente des diastolischen Einstromwiderstandes ist frequenzunabhängig.
    Notes: Summary When the heart is stimulated artificially by way of the right auricle after elimination of the sinus node, systolic and diastolic times are normal in the studied range of 60–220 beats per minute. When the intravascular component of coronary resistance is kept constant by way of a pharmacological maximal dilatation, an increase of extravascular resistance can be observed in all experiments with increased heart rate. This increase is caused by the relative increase of systolic time and the decrease of diastolic time. The increase of resistance is relatively small, because the decrease of systolic inflow resistance counterbalances the effect of lengthening of systole. The extravascular component of diastolic inflow resistance is independent of heart rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586386
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Die extravasale Komponente des Coronarwiderstandes bei Steigerung der linksventrikulären Druckanstiegsgeschwindigkeit durch Isoproterenol (1971)
    Springer
    Pflügers Archiv 325 (1971), S. 323-333 
    Details
    ISSN: 1432-2013
    Keywords: Coronary Blood Flow ; Extravascular Resistance ; dp/dt max ; Systolic Time ; Isoproterenol ; Coronardurchblutung ; extravasaler Widerstand ; dp/dt max ; Systolenzeit ; Isoproterenol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In Experimenten an narkotisierten Hunden wurde durch intracoronare Isoproterenolinfusionen die maximale Druckanstiegsgeschwindigkeit im linken Ventrikel (dp/dt max) vergrößert. Dabei wurde nach Ausschaltung des Sinusknotens die Herzfrequenz durch elektrische Reizung des rechten Herzohres konstant gehalten. Die intravasale (metabolisch regulierte) Komponente des Einflußwiderstandes wurde durch eine maximale pharmakologische Dilatation konstant gehalten. Die extravasale Komponente des Einflußwiderstandes steigt mit zunehmendemdp/dt max an, und zwar während der Systole. Der diastolische Einflußwiderstand bleibt konstant. Da gleichzeitig die Diastole auf Kosten der Systole länger wird, ist der Widerstandsanstieg während des ganzen Herzcyclus relativ gering.
    Notes: Summary In experiments on anaesthetized dogs the maximal rate of intraventricular pressure rise (dp/dt max) was enhanced by intracoronary infusions of isoproterenol. Heart rate was kept constant by electrical stimulation of the auricle afterelimination of the sinus node. The intravascular component (metabolically regulated) of coronary resistance was kept constant by a maximal pharmacological dilatation. The extravascular component of the inflow resistance increases with increasingdp/dt max but only during systole. The diastolic resistance remains unchanged. Since in addition the systole becomes shorter and the diastole longer, the rise of resistance during the whole cycle is relatively small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592173
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Extravasale Komponente des Coronarwiderstandes und Coronardurchblutung bei steigendem enddiastolischen Druck (1971)
    Springer
    Pflügers Archiv 327 (1971), S. 225-233 
    Details
    ISSN: 1432-2013
    Keywords: Extravascular Resistance ; Enddiastolic Pressure ; Coronary Blood Flow ; Systolic Time ; Barbiturates ; Extravasaler Widerstand ; Enddiastolischer Druck ; Coronardurchblutung ; Systolenzeit ; Barbiturate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In Experimenten an narkotisierten Hunden wurde durch i.v. Injektionen eines Barbiturates bei gleichzeitigen Bluttransfusionen, die den arteriellen Blutdruck konstant hielten, der enddiastolische Druck im linken Ventrikel erhöht. Die Herzen wurden nach Ausschalten des Sinusknotens über das rechte Herzohr elektrisch mit 150 Impulsen in der Minute stimuliert. Die metabolische Komponente des Einflußwiderstandes wurde durch eine pharmakologische, maximale Dilatation der Coronargefäße konstant gehalten. Die Coronardurchblutung bei maximaler pharmakologischer Dilatation sinkt mit steigendem end-diastolischen Druck ab. Die extravasale Komponente des Einflußwiderstandes steigt mit zunehmendem enddiastolischen Druck während der Systole, der Diastole und des Gesamtcyclus an. Die Systolendauer nimmt mit steigendem enddiastolischen Druck zu.
    Notes: Summary In experiments on anaesthetized dogs the enddiastolic pressure was gradually raised by intravenous application of a barbiturate and simultaneous arterial blood transfusion, which kept the arterial blood pressure constant. After elimination of the sinus node the heart rate was kept constant at 150 beats per minute by electrical stimulation of the right auricle. The metabolically regulated component of coronary resistance was kept constant by a maximal pharmacological dilatation. The coronary blood flow decreases with increasing enddiastolic pressure. The extravascular component of the inflow resistance increases with increasing enddistaolic pressure during systole, diastole, and the whole cycle. The duration of systole becomes longer with increasing diastolic pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586860
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Coronardurchblutung bei Erhöhung des arteriellen Kohlensäuredrucks (1971)
    Springer
    Pflügers Archiv 328 (1971), S. 170-175 
    Details
    ISSN: 1432-2013
    Keywords: Coronary Blood Flow ; Carbonic Acid Concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 9 dogs the heart rate was kept constant by electrical stimulation of the right auricle after elimination of the sinus node. Hypercapnia was induced by increasing inspiratory carbonic acid concentration at constant oxygen concentration. The mean arterial carbonic acid partial pressure increased from 40.5 to 70.5 mm Hg. The mean pH decreased from 7.30–7.14. Under these conditions the coronary flow did not change. Systolic and diastolic aortic pressure, left ventricular pressure, and the maximal rate of pressure rise in the left ventricle remained unchanged. Alterations of coronary blood flow caused by increased carbonic acid concentrations as described by other authors can be explained by a change of hemodynamic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592444
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    Paper (German National Licenses)
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