ABSTRACT
This study was designed to evaluate pediatric control patients during head-up tilt in comparison with symptomatic neurocardiogenic syncope patient head-up tilt responses. Twenty-three pediatric control (c) patients (13 females, 10 males; 11.9 +/- 3.1 years) were tested with head-up tilt (HUT) and compared with 66 symptomatic (s) patients. Baseline drug-free HUT (cHUT-1), a second drug-free HUT (cHUT-2), and a final HUT with isoproterenol infusion (cHUT-3) were each performed at 80 degrees tilt angle for 30 min or until positive. For comparison, 66 symptomatic patients (41 females, 25 males; 13.6 +/- 2.5 years) underwent drug-free HUT (sHUT-1); negative responders during sHUT-1 underwent follow-up HUT with isoproterenol (sHUT-2). HUT data were compared for both groups at both 30 and 20 min tilt duration. Twelve control patients (52%) had a symptomatic response during cHUT-1 at 18 +/- 8 min. During cHUT-2, 5 of 23 patients were positive at 13 +/- 5 min; each had previously tested positive during cHUT-1. Two patients, each positive in cHUT-1 and cHUT-2, refused cHUT-3. The only patient testing positive during cHUT-3 was test positive in cHUT-1 but negative for cHUT-2. In comparison, 43 of 66 (65%) symptomatic patients tested positive during drug-free sHUT-1 at 11 +/- 6 min. Subsequently, 20 of the 23 negative patients underwent HUT with isoproterenol (sHUT-2), with 8 of 20 testing positive. Thus, 51 of 66 symptomatic patients (77%) were called "true positives."(ABSTRACT TRUNCATED AT 250 WORDS)
