13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-210

Baroreceptor function during head up tilt test in patients with neurocardiogenic syncope

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

Materials and methods

We studied 13 patients (NS) with a history of neurocardiogenic syncope (mean age 30 ± 4 yrs; 7 male, 6 female). Twenty-two normal subjects (mean age 28 ± 10 yrs; 12 male, 10 female) made up the control group (CONTR).

All subjects underwent a first phase of 5 minutes during which they remained supine (BS), then they underwent a tilt-up test (TUT) at 70° degrees for 30 minutes or until the development of symptoms. Systolic blood pressure (SBP) and RR interval were continuously monitored during both BS and TUT. BRS was measured during baseline and during the first 5 minutes of the TUT by the sequences method. The time series of RR and SBP recorded during the BS and TUT phases were scanned using a software capable of identifying the sequences in which RR and SBP concurrently increased or decreased over three or more beats. The minimum change had to be 1 mmHg for SBP and 4 msec for RR. The linear correlation between RR and SBP was computed for each sequence; if the r value was > 0.80, the software calculated the regression coefficient or slope, which was taken as a measure of BRS and expressed in ms/mmHg. The mean BRS values and the percentage of beats involved in a sequence (Perc) were computed during BS and TUT for each patient.