A prospective 1-year study of postural tachycardia and the relationship to non-postural versus orthostatic symptoms

Healthy subjects with asymptomatic postural tachycardia at baseline were evaluated over a one year period to determine whether they developed non-postural versus orthostatic symptoms that could predispose them to develop Postural Tachycardia Syndrome (POTS). Participants (n=30) were recruited for a 1-year follow-up (FUP) study if at baseline they demonstrated a heart rate increment of ≥30bpm on head-up tilt (HUT). At FUP, HUT was repeated and four self-report questionnaires were used to assess symptoms. Heart rate (HR) increment was reduced in 19 subjects (-11.8±7.4bpm) and increased in 11 subjects (8.3±6.1bpm) at FUP versus baseline. Heart rate increment at FUP demonstrated no correlation to general fatigue (r=0.006), body vigilance (r=0.195), or the component scores for physical (r=-0.087) and mental (r=-0.137) health of the SF-36. Similarly, there was no correlation between HR increment at FUP and orthostatic scores (r=0.04). However, orthostatic scores did show a significant positive correlation with general fatigue and body vigilance scores (r=0.374, r=0.392, respectively; p<0.05). Despite meeting the heart rate criteria for POTS, these findings further support that the majority of young individuals express benign orthostatic tachycardia. In addition, after one year this patient population showed no predisposition to develop non-postural or postural symptoms that could lead to the full syndrome of POTS. These data further argue for the re-evaluation of the heart rate criteria for diagnosing POTS in young populations.