Myocardial Protection

Eric N. Feins, MD, Constantine D. Mavroudis, MD, Damien J. LaPar, MD, MSc

Key Points

  • Patients with HLHS require lifelong longitudinal medical care and follow-up.
  • Pediatric myocardial protection focuses on reducing ischemia-reperfusion injury and supporting recovery after surgery.
  • The chapter notes that the immature myocardium has unique metabolic and physiologic features that impact how it responds to ischemia and protection strategies of myocardial protection.
  • Hypothermia is described as a critical part of myocardial protection because it lowers oxygen consumption in the heart (and other organs).
  • Cardioplegia is commonly used with hypothermia to arrest the heart and further reduce myocardial energy demand during surgery.
  • The chapter also emphasizes the importance of avoiding cardiac distention and anticipating low cardiac output syndrome in the early postoperative period.
  • The immature myocardium is not just a smaller adult heart.
    • The chapter emphasizes that the immature myocardium has distinct metabolic and cellular properties, and is “generally felt… more tolerant of ischemia than the mature/adult myocardium,” although some features of immaturity also increase vulnerability.
  • Congenital physiology can change how well the heart tolerates surgery.
    • Chronic pressure load, volume load, and cyanosis can produce myocardial changes that impact protection and recovery, so myocardial preservation has to account for the underlying lesion and physiology.
  • Myocardial protection depends on hypothermia, cardioplegia, and decompression.
    • The chapter identifies the following concepts as central strategies of pediatric myocardial protection, noting that important features are unique to children and relate to “the use of hypothermia, types of cardioplegia, and strategies to vent the child’s heart.”
  • Avoiding ventricular distention is a major technical priority.
    • The authors stress that the immature myocardium is “significantly more vulnerable to the negative effects of ventricular distention,” making careful venting and decompression essential during cardiopulmonary bypass and delivery of cardioplegia.
  • No single cardioplegia strategy has been proven universally superior.
    • The chapter notes that protocols vary widely across centers, and conflicting studies make it difficult to recommend one approach over another; tailoring the strategy to the patient and anatomy remains important.

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