Interaction of heart rate and hypothermia on global myocardial contraction of the isolated rabbit heart

Anesthesia and Analgesia
M MattheussenW Flameng

Abstract

We studied the effects of mild hypothermia on cardiac contractility in isolated rabbit hearts perfused with Krebs-Henseleit solution according to the technique of Langendorff. Isovolumetric left ventricular pressure (LVP) was measured with a fluid-filled balloon. Hearts were paced after induction of atrioventricular block. At low heart rates ( < 30 bpm) mild hypothermia (cooling to 30 degrees C) induced a 32% increase in LVp (146.5 +/- 10 mm Hg at 30 degrees C vs 110.7 +/- 13 mm Hg at 37 degrees C) but this positive inotropic response was progressively lost by increasing heart rate. At pacing rates > or = 90 bpm, lower systolic LVP, higher diastolic LVP, and lower positive and negative LV dP/dt were obtained in hypothermic (93 +/- 12 mm Hg, 55 +/- 18 mm Hg, 584 +/- 137 mm Hg/s, and 323 +/- 57 mm Hg/s at 210 bpm, respectively) compared to normothermic hearts (123 +/- 4 mm Hg, 10 +/- 4 mm Hg, 1705 +/- 145.5 mm Hg/s, and 1155 +/- 78 mm Hg/s at 210 bpm, respectively.) The duration of mechanical diastole was reduced or suppressed in these hearts. Exposure to the beta-adrenoreceptor agonist, isoproterenol, improved this diastolic dysfunction during hypothermia and pacing at high rates, suggesting that the sarcoplasmic reticulum Ca2+ ...Continue Reading

References

Jul 1, 1976·Acta Physiologica Scandinavica·A R Mattiazzi, E Nilsson
Jul 28, 1975·Pflügers Archiv : European journal of physiology·G Isenberg, W Trautwein
Oct 1, 1985·Pflügers Archiv : European journal of physiology·A CavaliéW Trautwein
Jan 1, 1989·Heart and Vessels·M Fukunami, D J Hearse
Sep 1, 1967·Archives of Biochemistry and Biophysics·G Inesi, S Watanabe
Jan 1, 1954·Circulation Research·R M BERNE
Jan 1, 1951·The American Journal of Physiology·K E PENROD, J FLYNN

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Citations

Dec 2, 2005·Journal of Investigative Surgery : the Official Journal of the Academy of Surgical Research·Uwe M FischerSteven J Allen
Oct 10, 2012·Resuscitation·Stephan Schmidt-SchwedaBurkert Pieske
Dec 14, 2011·Resuscitation·Xinrong HeJean-Louis Vincent
Jan 5, 2002·Journal of the American College of Cardiology·Michael E LewisRobert S Bonser
Jul 14, 2018·American Journal of Physiology. Heart and Circulatory Physiology·Halvard G HiisKurt A Krobert

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