No abstract

There was no difference in the proportion of patients discharged early despite more patients being classified as low risk by the EDACS-ADP than the ADAPT-ADP. Both accelerated diagnostic pathways are effective strategies for chest pain assessment and resulted in an increased rate of early discharges compared with previously reported rates.

In part I of this study, we found that the classical studies on vasovagal syncope, conducted in fit young subjects, overstated vasodilatation as the dominant hypotensive mechanism. Since 1980, blood pressure and cardiac output have been measured continuously using noninvasive methods during tilt, mainly in patients with recurrent syncope, including women and the elderly. This has allowed us to analyze in more detail the complex sequence of hemodynamic changes leading up to syncope in the laboratory. All tilt-sensitive patients appear to progress through 4 phases: (1) early stabilization, (2) circulatory instability, (3) terminal hypotension, and (4) recovery. The physiology responsible for each phase is discussed. Although the order of phases is consistent, the time spent in each phase may vary. In teenagers and young adults, progressive hypotension during phases 2 and 3 can be driven by vasodilatation or falling cardiac output. The fall in cardiac output is secondary to a progressive decrease in stroke volume because blood is pooled in the splanchnic veins. In adults a fall in cardiac output is the dominant hypotensive mechanism because systemic vascular resistance always remains above baseline levels.