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. 2011:2011:659787.
doi: 10.5402/2011/659787. Epub 2011 Apr 14.

What Happens before Syncope? Study of the Time Frame Preceding Vasovagal Syncope

Alfonso Lagi  1 , Simone Cencetti, Alessandro Cartei
Affiliations

What Happens before Syncope? Study of the Time Frame Preceding Vasovagal Syncope

Alfonso Lagi et al. ISRN Cardiol. 2011.

Abstract

Objective. The events characterizing the very last part of the vasovagal crisis has not been determined. The aim of the study was to analyze the variations in respiratory pattern preceding the vaso-vagal syncope full-blown and the relationship between cardiovascular functions in order to assess the temporal sequence. Methods. Eleven consecutive patients were studied. Heart rate, arterial pressure, respiratory frequency, tidal volume, carbon dioxide, and oxygen saturation in time domain from supine and standing recordings were analyzed. Results. The respiratory activity is different in the time frame preceding syncope, both in V(T) and breathing rate, and that the increase of the lung ventilation does not influence the baroreflex control during the presyncopal period but may be cause of the baroreflex failure during the full-blown syncope.

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Figures

Figure 1
Figure 1
Mean of heart rate, systolic arterial pressure, tidal volume, respiratory frequency, CO2 and O2 saturation in different study periods. Abbreviations: VVS: vaso-vagal syncope; SAP: systolic arterial pressure; RF: respiratory frequency; VT: tidal volume; HR: heart rate; OP: early orthostatic phase; PP: preceding phase.
Figure 2
Figure 2
Hypothetical steps of baroreflex failure in syncope.
See this image and copyright information in PMC

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