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Basic Research in Cardiology

, Volume 74, Issue 6, pp 639–648 | Cite as

Pulsus alternans in regionally hypoxic ventricles of open-chest dogs: Regional mechanical alternation of potentiation and attenuation of the inotropic state

  • B. Crozatier
  • D. Caillet
  • P. Jouannot
  • P. Y. Hatt
  • P. Gastineau
Original Contributions

Summary

Sustained mechanical alternation appeared after a spontaneous premature ventricular contraction in 6 open-chest dogs during the perfusion of the left circumflex coronary artery by Krebs-Henseleit solution equilibrated with 5% CO2 and 95% N2. The animals were instrumented with a catheter in the left ventricle and ultrasonic crystals in hypoxic and control segments. Left ventricular systolic pressure was significantly higher in the strong than in the weak beats with no significant difference of end-diastolic lengths in hypoxic and control segments. In hypoxic segments, systolic shortening was significantly larger in strong beats (11.9±1.9%) as compared with weak beats (5.1±1.6%) and with control beats preceding the premature ventricular contraction (9.7±1.6%) but the postextrasystolic beat was larger (17.9±1.3%). There was no significant change of systolic shortening in control segments during mechanical alternation which appears thus as a regional phenomenon which cannot be explained by the Starling mechanism: instead, alternation is attributed to a change of excitation-contraction coupling after a premature contraction with alternation of potentiation and attenuation of the inotropic state.

Keywords

Premature Ventricular Contraction Ventricular Systolic Pressure Starken Control Segment Left Circumflex Coronary Artery 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Pulsus alternans bei Hunden mit regionaler Myokardhypoxie: Örtliches Alternieren von Potenzierung und Abschwächung des inotropen Status

Zusammenfassung

Bei 6 Hunden mit offenem Thorax trat unter Perfusion des R. circumflexus der linken Koronararterie mit sauerstoff-freier Krebs-Henseleit-Lösung (äquilibriert mit 5% CO2, 95% N2) ein langdauernder mechanischer Alternans auf. Bei den Tieren wurde ein Katheter im linken Ventrikel sowie Ultraschallkristalle in den hypoxischen und Kontroll-Segmenten plaziert. Der systolische Druck des linken Ventrikels war bei den starken Schlägen signifikant höher als bei den schwachen, während keine signifikante Differenz bezüglich der Länge in hypoxischen und Kontrollsegmenten bestand. In hypoxischen Segmenten war die systolische Verkürzung bei den starken Schlägen deutlich größer (11,9±1,9%) als bei den schwachen (5,1±1,6%). Jedoch war der postextrasystolische Schlag stärker (17,9±1,3%). In den Kontrollsegmenten war keine signifikante Änderung der systolischen Verkürzung während des mechanischen Alternierens zu verzeichnen. Letzteres ist daher offenbar ein regionales Phänomen, welches nicht durch den Starling-Mechanismus erklärt werden kann. Das Alternieren wird vielmehr auf eine Änderung der elektromechanischen Kopplungsbedingungen nach einer Extrasystole bezogen mit abwechselnder Potenzierung und Abschwächung des inotropen Status.

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Copyright information

© Dr. Dietrich Steinkopff Verlag 1979

Authors and Affiliations

  • B. Crozatier
    • 1
  • D. Caillet
    • 1
  • P. Jouannot
    • 1
  • P. Y. Hatt
    • 1
  • P. Gastineau
    • 1
  1. 1.Hôpital Léon BernardM.D., I.N.S.E.R.M. U2Limeil-BrévannesFrance

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