[Usefulness of the tilt test with nitroglycerine application in diagnosing of patients with unexplained syncope: new aspects of the well-known problem].
BACKGROUND
The head-up tilt test (TT) performed after sublingual nitroglycerine application (NTG) is a tool that is commonly accepted and widely used in diagnosing patients with unexplained syncope. Although the results of conducted trials suggest advantages related to the protocol of TT with NTG, but data concerning the special diagnostic value of this protocol and the circumstances when it is superior to the passive TT, have not been established yet. The aim of the study was to analyse the problem whether there is, and if so, what circumstances it is related to, any special value of TT with NTG in diagnosing patients with vasovagal syncope.


METHODS
112 subjects were examined, 67 men and 45 women, at the mean age 34.4 +/- 19.1, and 42.6 +/- 17.4 years (p = 0.07), respectively, with at least two events of unexplained syncope. The control group consisted of 35 healthy volunteers matched for age and sex (18 men and 17 women), at the mean age 39.4 +/- 12.6 years (18-77 years) without syncope in anamnesis. All patients underwent a passive tilt test (Westminster protocol- 60 degrees/45 min) and in the case of lacking response to the passive test, the patients received 0.25 mg NTG and the test was continued over the next 20 minutes. The type of syncope reaction was determined based on the ACC classification (1996). If vasovagal syncope occurred, its type was defined according to the VASIS classification.


RESULTS
The passive TT defined the reason of syncope in 31 patients (28% of all examined subjects), whereas TT with NTG increased this group by another 37 patients (33%), so that 68 patients (61%) were diagnosed using both protocols. The analysis of the study population that was sensitive to TT revealed that the group of patients who had vasovagal syncope during the test was greater than the group of patients who had other, i.e. non-vasovagal, type of reaction (48 vs 20, p = 0.002). There was a statistically significant relationship between the method of provocation and the type of reaction (chi 2 = 6.8, p = 0.009). The age difference between the groups of patients who developed vasovagal reaction during passive TT and patients who developed this type of reaction during TT with NTG (27.3 +/- 11.5 vs 39.9 +/- 20.3, p = 0.005) was also statistically significant. In the context of these results, concerning the mentioned groups of patients, the dichotomy division index of age was established: which was 30 and 50 years, respectively. A statistically significant relationship was found between the sex of the study population and the type of provocation (passive TT vs TT with NTG) resulting in syncope in sensitive patients (chi 2 = 2.84, p = 0.009). Fourteen (70%) women and only 23 (48%) men required NTG in order to establish the diagnosis, i.e. vasovagal background of syncope.


CONCLUSIONS
1. Vasovagal syncope seems to be a highly specific form of circulatory response to TT and requires application of NTG statistically more often than other types of neurocardiogenic reactions. 2. TT with NTG is especially justified in women and patients of either sex older than 50 years.
Gielerak
Grzegorz
G
Klinika Chorób Wewnetrznych i Kardiologii Centralnego Szpitala Klinicznego Wojskowej Akademii Medycznej w Warszawie. gielerak@cskwam.mil.pl
Makowski
Karol
K
Dłuzniewska
Ewa
E
Roszczyk
Anna
A
Cholewa
Marian
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D018475:Head-Down Tilt; D006801:Humans; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013575:Syncope / Q000175:diagnosis* / Q000188:drug therapy*; D014665:Vasodilator Agents / Q000627:therapeutic use*
D014665:Vasodilator Agents; D005996:Nitroglycerin