RT-210
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Baroreceptor function during
head up tilt test in patients with neurocardiogenic syncope
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Andrea Passantino, Nicola Di
Venere*, Cinzia Forleo, Francesco Massari, Paolo Totaro, Filippo Mastropasqua, Maria
Vittoria Pitzalis*, Paolo Rizzon*.
Cardiology "Maugeri" Foundation, IRCCS, Cassano, *Institute of
Cardiology, University of Bari, Italy
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Abstract
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To investigate the role of impaired baroreflex
sensitivity (BRS) in the pathophysiology of neurocardiogenic syncope, we studied 13
subjects (age 30 ± 4 yrs; 7M, 6F) with a history of > 3/year syncopes, without
cardiovascular or neurological disease, and a tilt-up test (TUT) positive for syncope or
presyncope after a mean time of 19 ± 11 min. A control group of 22 normal volunteers (28
± 10 yrs; 12M, 10F) was also studied. In both groups ECG and noninvasive systolic blood
pressure were monitored and recorded for 5 minutes before TUT in supine position (BS), and
throughout the TUT. We analysed the recordings obtained from BS and the first 5 minutes of
the positive TUT. BRS was analysed by using the sequence method: sequences were identified
from simultaneously recorded time series in which RR interval (RR) and systolic blood
pressure (SBP) concurrently increased or decreased; for each sequence the linear
correlation between RR and SBP was computed; if the r value was > 0.80 the software
calculated the regression coefficient or slope. For BS and TUT we computed the mean BRS
and the percentage of beats involved in a sequence (Perc).
In patients with neurocardiogenic syncope, BRS during BS and TUT is not different from
normal subjects; however during the early minutes of the TUT, patients had a lower
percentage of beats involved in a sequence; this suggests that in this phase the pattern
of autonomic control of circulation in patients who will develop syncope is different from
the pattern controls.
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Key Words
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Autonomic nervous system evaluation
neurocardiogenic syncope, baroreceptor function, head-up tilt testing, autonomic control
of circulation, OA
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