Neuroscience Journal

Research Article

Cerebral Blood Flow, Heart Rate, and Blood Pressure Patterns during the Tilt Test in Common Orthostatic Syndromes

Table 1

Criteria for the orthostatic syndromes.
Disorder/syndromeCriteriaComments
Normal response to tiltQASAT —bradycardia supine = 0 AND
QASAT —increased heart rate response to tilt = 0
QASAT —orthostatic hypotension during the tilt = 0 AND
QASAT —orthostatic hypertension during the tilt = 0 AND
QASAT —cerebral blood flow response to tilt = 0 		 
Orthostatic hypotension (OH), compensated, with stable orthostatic CBFvQASAT —orthostatic hypotension during the tilt > 0 AND
QASAT —cerebral blood flow response to tilt = 0		 
OH, uncompensated, with reduced orthostatic CBFvQASAT —orthostatic hypotension during the tilt > 0 AND
QASAT —cerebral blood flow response to tilt > 0		 
Orthostatic cerebral hypoperfusion syndrome (OCHOs)QASAT —orthostatic hypotension during the tilt = 0 AND
QASAT —cerebral blood flow response to tilt > 1 AND
QASAT —increased heart rate response to tilt = 0		 
Orthostatic hypertension syndrome (OHTN)QASAT —orthostatic hypotension during the tilt = 0 AND
QASAT —orthostatic hypertension during the tilt = 1 AND
QASAT —cerebral blood flow response to tilt = 0 AND
QASAT —increased heart rate response to tilt = 0		 
Postural tachycardia syndrome (POTS)QASAT —orthostatic hypotension during the tilt = 0 AND
average supine heart rate before the tilt < 100 BMP AND
maximal heart rate increment during the tilt ≥ 30 BMP AND
the duration of the increment ≥ 3 minutes AND
the maximal absolute heart rate during the increment ≥ 120 BPM		If the maximal heart rate does not cross 120 BMP, it is called mild orthostatic intolerance
Inappropriate sinus tachycardia (IST)QASAT —orthostatic hypotension during the tilt = 0 AND
average supine heart rate before the tilt ≥ 100 BMP AND
heart rate increment during the tilt ≥ 30 BMP		Grading is based on maximal heart rate
Paroxysmal sinus tachycardia (PST)QASAT —orthostatic hypotension during the tilt = 0 AND
average supine heart rate before the tilt < 100 BMP AND
maximal heart rate increment during the tilt ≥ 30 BMP AND
the duration of the increment < 3 minutes AND
the maximal absolute heart rate during the increment ≥ 120 BPM		PST usually affects the first 2 minutes of the tilt but not always. If, for example, the tachycardia with the 30 BPM increment occurs at minutes 9 and 10 of the tilt (the tachycardia duration = 2 minutes), then it is recommended to continue the tilt to clarify the diagnosis. If the tachycardia continues it is the POTS; if not it is PST
Syncope, cardiovagalHR < 40 BPM AND
systolic BP < 60 mmHg AND
diastolic CBFv < 5 cm/sec		All variables are obtained during the syncope
Syncope, vasodepressorHR ≥ before syncope AND
systolic BP < 60 mmHg AND
diastolic CBFv < 5 cm/sec		All variables are obtained during the syncope
Syncope, mixedHR > 40 BPM AND
HR < before syncope AND
systolic BP < 60 mmHg AND
diastolic CBFv < 5 cm/sec 		All variables are obtained during the syncope
Primary cerebral autoregulatory failure QASAT —supine cerebral low flow = 1 AND
QASAT —supine hypotension = 0		 
Psychogenic pseudosyncopeQASAT —cerebral blood flow response to tilt = 0 AND
physical examination indicative of apparent loss of consciousness		Typically patient is unresponsive, atonic, although bizarre posturing can be observed, without abnormal movement that can be seen in seizures
Comments: QASAT = Quantitative Scale for Grading of Cardiovascular Autonomic Reflex Tests and Small Fibers from Skin Biopsies, details of calculations can be found in Novak, 2015 [6]. HR = heart rate; BP = blood pressure; CBFv = cerebral blood flow velocity.