Figure 1.
Original tracings of blood pressure (upper tracings) and heart rate (lower tracings) in four representative individuals who experienced a cardioinhibitory response with asystole (VASIS class IIb) during head-up tilt.
Black and white arrows indicate the onset of hypotension and bradycardia, respectively. Hypotension preceded the onset of bradycardia in most (Panels A–C) but not all patients (Panel D). Panel A: female, 33 years; panel B: female, 52 years; panel C: female 17 years; panel D: female, 32 years.
Table 1.
Modified VASIS classification [15].
Table 2.
Clinical data of patients - age quartiles.
Figure 2.
Individual data and mean±SEM in the difference between the onset of hypotension and the onset of bradycardia stratified for age quartiles.
Hypotension preceded the decrease in heart rate in all but six individuals (97%) irrespective of age.
Figure 3.
Individual data and mean±SEM in the difference between the onset of hypotension and the onset of bradycardia for those patients who experienced asystole during head-up tilt (VASIS class IIb).
Hypotension preceded the decrease in heart rate in all but one individual (91%).
Table 3.
Clinical data of patients.
Figure 4.
Mean values of heart rate (upper panel) and mean blood pressure (lower panel) at 5 sec intervals in the supine position, during early head-up tilt (HUT), and during tilt-induced (pre)syncope stratified for age (green: 1st quartile, 12–24 years, n = 26; blue: 2nd quartile, 25–42 years, n = 27; violet: 3rd quartile, 43–57 years, n = 36; red: 4th quartile, 58–79 years, n = 20).
The vertical lines indicate the onset of decreases in heart rate and blood pressure, respectively. Younger patients had a larger increase in heart rate with head-up tilt. However, the onset of hemodynamic events began earlier with increasing age. Furthermore, the decrease in heart rate upon tilt-induced (pre)syncope was progressively blunted with increasing age.
Figure 5.
Occurrence of cardioinhibitory responses with asystole (VASIS IIb) for age quartiles.
Asystole became progressively rarer with increasing age (p<.05).
Table 4.
Hemodynamics at rest and upon (pre)syncope - age quartiles.