ABSTRACT
BACKGROUND: Delirium is a common condition with poorly understood pathophysiology. Various theories have been proposed including that delirious patients have reduced cerebral blood flow. We hypothesised that patients with delirium could have abnormal autonomic nervous system function, as assessed by tilt table testing, which would explain the alteration in blood flow. METHODS: A prospective cohort study of medical inpatients aged 65 years and older was undertaken. Delirium was assessed using DRS-R98 and DSM-IV criteria. Beat-to-beat blood pressure (BP) was recorded during tilt testing. Differences in BP changes between the two groups (those with delirium and those without) were explored. The association between severity of delirium and magnitude of BP changes was also examined. RESULTS: 64 participants were recruited during hospitalisation. 29 completed follow-up Head-Up Tilt testing. The mean age of participants was 80.8 years (SD 6.2 years). The control group (n = 12) had a median decrease in systolic BP of 17.5 mmHg (IQR 20.75). The delirium group (n = 17) had a median decrease in systolic BP of 1 mmHg (IQR 38.5), p = 0.04. As delirium severity scores increased, systolic BP change during tilting also increased (rs = 0.42, p = 0.03). CONCLUSION: Participants in the delirium group showed different BP responses to tilt test which may represent abnormal sympathetic response. This would be consistent with other features of delirium such as treatment response to centrally acting alpha-2 blockers. Equity of access to research for older, frail and delirious cohorts is essential but feasibility and acceptability needs to be optimised and factored into study design.
Subject(s)
Delirium , Hypotension, Orthostatic , Aged, 80 and over , Autonomic Nervous System , Blood Pressure , Delirium/diagnosis , Humans , Prospective Studies , Tilt-Table TestABSTRACT
AIMS: The aim of this study is to define the optimal duration of tilt testing for the assessment of patients with suspected postural tachycardia syndrome (POTS). METHODS AND RESULTS: This was a case-control study. Cases were identified retrospectively from a database of patients referred with orthostatic intolerance (OI). All met the diagnostic criteria for POTS. Controls were enrolled prospectively. All subjects underwent tilting to 70 degrees for 40 min if tolerated. Continuous monitoring was provided by a Finometer. Analysis of responses to tilting was performed on 28 cases and 28 controls. The mean age in the case group was 23.6 and in the control group was 26.2. The majority was female in both groups (cases = 4F:3M, controls = 2F:1M). All cases met the criteria for POTS within 7 min of orthostasis. No controls demonstrated a sustained tachycardia. The prevalence of vasovagal syncope (VVS) was 36% in cases vs. 7% in controls (P = 0.02) and 25% in the remaining patients (n = 233) on the OI database (P = 0.259). CONCLUSION: A 10 min tilt will diagnose POTS in the majority of patients. It will not, however, be sufficient to identify the overlap that exists between POTS and VVS. The optimal duration of tilt testing in patients suspected of POTS is 40 min.
Subject(s)
Postural Orthostatic Tachycardia Syndrome/diagnosis , Postural Orthostatic Tachycardia Syndrome/physiopathology , Tilt-Table Test/methods , Adult , Case-Control Studies , Female , Humans , Hypotension, Orthostatic/diagnosis , Hypotension, Orthostatic/etiology , Hypotension, Orthostatic/physiopathology , Male , Orthostatic Intolerance/diagnosis , Orthostatic Intolerance/etiology , Orthostatic Intolerance/physiopathology , Prevalence , Prospective Studies , Retrospective Studies , Syncope, Vasovagal/diagnosis , Syncope, Vasovagal/etiology , Syncope, Vasovagal/physiopathology , Tilt-Table Test/adverse effects , Time FactorsABSTRACT
A 21-year-old female reports an 18-month history of light-headedness on standing. This is often associated with palpitations and a feeling of intense anxiety. She has had two black-outs in the past 12 months. She is not taking any regular medications. Her supine blood pressure was 126/84 mmHg with a heart rate of 76 bpm, and her upright blood pressure was 122/80 mmHg with a heart rate of 114 bpm. A full system examination was otherwise normal. She had a 12-lead electrocardiogram performed which was unremarkable. She was referred for head-up tilt testing. She was symptomatic during the test and lost consciousness at 16 min. Figure 1 summarizes her blood pressure and heart rate response to tilting. A diagnosis of postural orthostatic tachycardia syndrome with overlapping vasovagal syncope was made.
Subject(s)
Orthostatic Intolerance/diagnosis , Orthostatic Intolerance/therapy , Postural Orthostatic Tachycardia Syndrome/diagnosis , Postural Orthostatic Tachycardia Syndrome/therapy , Tilt-Table Test/methods , Female , Humans , Young AdultABSTRACT
We report the case of an 18-year-old female who presented as an out-of-hospital ventricular fibrillation cardiac arrest. She required ICD insertion and recovered without deficit. Following recurrent syncopal episodes we diagnosed the co-existence of Neurocardiogenic syncope.
