Myocardial repair around-the-clock.

Abstract

> As an intern in 1952, we admitted patients with acute myocardial infarction wherever a bed was available on the medical service, but always as far from the nurses’ station as possible, so that they would not be disturbed by the commotion, especially the frequent telephone ringing. > > —Eugene Braunwald1 Significant advances in the diagnosis and management of patients with ischemic myocardial syndromes1,2 have occurred since Herrick’s classic description of acute myocardial infarction (MI) 102 years ago (1912). With progress in technology, it became clear that lethal ventricular arrhythmias were a common cause of death that could be prevented by immediate electric defibrillation of the heart. This led to the development of the modern coronary care units (CCU). These units facilitated continuous monitoring and defibrillation for life-threatening arrhythmias, the rapid treatment of recurrent myocardial ischemia, and early recognition and initiation of various therapies for pump failure and cardiogenic shock. Article, see p 1713 A consequence of the modern CCU environment (and critical care units in general) was the loss of the normal sleep–wake cycle for patients admitted to the busy critical care environment. Sleep is a restorative process, leading to important circadian variations in protein synthesis and cellular repair3 that affect many organs including the heart.4 Inadequate sleep induces a state of catabolism and impaired immunity, which may lead to delayed wound healing5,6 and altered myocardial energetics.7 With continued progress, the emphasis of CCU care has shifted to improving outcomes by reducing infarct size with early reperfusion frequently implemented with primary percutaneous coronary intervention during the initial hours of infarction. With this, time spent in the CCU is frequently <24 hours, with discharge to home within 72 hours. Thus, for contemporary patients, the synchrony between endogenous biological clocks and the external circadian …