[Hibernating and stunned myocardium. Pathogenetic mechanisms during and after myocardial ischemia].

In this paper the Authors consider the concept of stunning/hibernating myocardium, analizing the most recent articles and reviews in literature, until April 2002 (database PubMed). Dysfunctional segments with normal perfusion and normal glucose utilization are considered to be "stunned", and dysfunctional segments with reduced perfusion and preserved glucose utilization are considered to be "hibernated". Together with the two major hypothesis (generation of oxygen-derived free radicals and transient calcium overload) in developing of dysfunctional myocardium after ischaemia, recent studies have demonstrated an important role in down-regulation of beta-adrenergic receptors both in the stunned and in the hibernated segments. Moreover, the increase of negatively inotropic cytokines TNF-alpha and NOS2 has been observed in dysfunctional segments. The number of copies of mRNA has been quantified by reverse transcription-polymerase chain reaction (reverse-PCR).