14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-183

A new classification of the haemodynamics of vasovagal syncope. Analysis of the preparatory (pre-syncopal) phase of the tilt testing without and with nitroglycerin challenge

Carlo Menozzi, Michele Brignole*, Attilio Del Rosso**, Silvia Costa*, Germano Gaggioli*, Alberto Solano*, Nicola Bottoni, Paolo Bartoli**, Richard Sutton***.
Arrhythmologic Centre, Ospedale S. Maria Nuova, Reggio Emilia, *Arrhythmologic Centre, Ospedali Riuniti, Lavagna, **Department of Cardiology, Ospedale S. Pietro Igneo, Fucecchio, Italy, ***Department of Cardiology, Royal Brompton Hospital, London, UK

Abstract

We believe that the pattern of blood pressure response to tilt during the time preceding the development of the vasovagal reaction may provide adjunctive diagnostic information. A group of 101 consecutive patients affected by syncope of uncertain origin underwent passive tilt testing for 45 min at 60° followed, if negative, by oral trinitroglycerin (TNG) 0.4 mg. with continuation of the test for 20 min. Three main patterns were observed: the classic syncope pattern was observed in 36 patients who, during the preparatory phase, had a rapid and full compensatory reflex adaptation to upright position, resulting in stabilization of their blood pressure values until abrupt onset of the vasovagal reaction; the dysautonomic syncope pattern was observed in 47 patients in whome steady-state adaptation to upright position and was not possible. There was thus a progressive fall in their blood pressure until the occurrence of a typical vasovagal reaction; the orthostatic intolerance pattern was observed in 18 patients in whome there was a proggressive fall in blood pressure, similar to that of the dysautonomic group, but this was not followed by a clear vasovagal reaction. Compared with the classic, the dysautonomic patients were older, had a higher prevalence of comorbidities, a very much shorter history of syncopal episodes, and a prevalence of mixed and vasodepressor forms of the VASIS classifications. The patients with the orthostatic intolerance had clinical characteristics similar to the dysautonomic group but they could not be classified according to the VASIS classification. In conclusion, in patients with syncope, a variety of abnormal responses is observed during the tilt testing suggesting that different syndromes can be diagnosed by the test. A more detailed, although still arbitrary, classification may form the basis of a number of future drug and pacemaker trials, as well as help towards a greater understanding of the different mechanisms of tilt-induced syncope.

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