HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Dominique Shum-Tim Christo I. Tchervenkov Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Shum-Tim, D. Articles by Chiu, R. C.- J. Search for Related Content PubMed PubMed Citation Articles by Shum-Tim, D. Articles by Chiu, R. C.- J.

Ann Thorac Surg 1994;57:311-318
© 1994 The Society of Thoracic Surgeons

---

Articles

Newborn myocardial protection after prolonged prearrest cooling: A calcium overload phenomenon?

Division of Cardiovascular and Thoracic Surgery, McGill University, Montreal, Quebec, Canada

^_* Address reprint requests to Dr Tchervenkov, The Montreal Children's Hospital, 2300 Tupper St, Montreal, Que, Canada H3H 1P3.

Prolonged cold perfusion of the nonarrested newborn heart has been shown to induce stunning and subsequent contracture when followed by ischemia. The underlying mechanism remains unknown. To test whether this phenomenon is due to cytosolic calcium (Ca²⁺) overload, a Ca²⁺-channel blocker (verapamil hydrochloride) was used to pretreat the newborn heart immediately before prolonged cold perfusion. Twenty-eight newborn piglets were studied in an isolated, Krebs-Henseleitperfused Langendorff cardiac model. Group I control hearts (n = 8) were subjected to 90 minutes of cold perfusion at 15 °C, followed by 90 minutes of global ischemia and then 30 minutes of normothermic reperfusion. Group II hearts (n = 6) were pretreated with verapamil (0.2 x 10^–7 mol/L) for 3 minutes prior to similar experimentation. Groups III (control, n = 8) and IV (verapamil pretreatment, n = 6) underwent the same protocol without ischemia. Baseline functional measurements were obtained with left ventricular balloon inflated at baseline pressure of 10 to 15 mm Hg prior to cold perfusion and after 30 minutes of normothermic reperfusion. Perfusate creatine kinase level was analyzed, and electron microscopic examination was performed at the conclusion of each experiment. Fifty percent of group I control hearts had no postischemic recovery, and ultrastructural study revealed marked contraction bands. Functional recovery was significantly improved (p < 0.05) in the group II verapamil-pretreated hearts: left ventricular developed pressure, 78.6% ± 3.0% (II)versus 17.3% ± 6.7% (I); positive first derivative of developed pressure, 81.9% ± 7.7% (II) versus 19.2% ± 7.5 (I); negative first derivative of developed pressure, 78.9% ± 6.0% (II) versus 14.6% ± 5.9% (I); and left ventricular end-diastolic pressure, 15.7% ± 1.7% (II) versus 56.8% ± 10.4% (I). Verapamil prevented the stunning effect of prolonged prearrest cold perfusion alone in the absence of ischemic insult (group IV): left ventricular developed pressure, 89.7% ± 3.8% (IV) versus 67.6% ± 2.7% (III); positive first derivative of developed pressure, 93.9% ± 3.2% (IV) versus 72.9% ± 4.6% (III); and negative first derivative of developed pressure, 94.1% ± 3.4% (IV) versus 72.6% ± 6.4% (III) (all, p < 0.05). Verapamil pretreatment significantly diminishes the adverse effects of prolonged hypothermic perfusion in the isolated newborn heart

This article has been cited by other articles:

				X.-H. Ning, C.-S. Xu, Y. C. Song, Y. Xiao, Y.-J. Hu, F. M. Lupinetti, and M. A. Portman Hypothermia preserves function and signaling for mitochondrial biogenesis during subsequent ischemia Am J Physiol Heart Circ Physiol, March 1, 1998; 274(3): H786 - H793. [Abstract] [Full Text] [PDF]