| Classification . | Test for diagnosis . | Time from standing to symptoms . | Pathophysiology . | Most frequent symptoms . | Most frequent associated conditions . |
|---|---|---|---|---|---|
Initial OH | Beat-to-beat SBP on lying-to-standing test (active standing) | 0–30s | Mismatch between CO and SVR | Light-headedness/dizziness, visual disturbances a few seconds after standing up (syncope rare) | Young subjects with asthenic habitus Old age, drug-induced (alpha-blockers), carotid sinus syndrome |
Classical OH (classical autonomic failure) | Lying-to-standing test (active standing) or tilt table | 30s–3min | Impaired increase in SVR in autonomic failure resulting in pooling of blood/or severe volume depletion overriding reflex adjustments | Dizziness, presyncope, fatigue, weakness, palpitations, visual and hearing disturbances (syncope rare) | Old age Drug-induced (any vasoactive drug) |
Delayed (progressive) OH | Standing Tilt table | 3–30min | Progressive fall in venous return: low CO, diminished vasoconstriction capacity (failing adaptation reflex), no reflex bradycardia) | Prolonged prodromes (dizziness, fatigue, weakness, palpitations, visual and hearing disturbances, hyperidrosis, low back pain, neck or precordial pain) frequently followed by rapid syncope | Old age Autonomic failure Drug-induced (any vasoactive drug) Comorbidities |
Delayed (progressive) OH + reflex syncope | Tilt table | 3–45min | Progressive fall in venous return (as above) followed by vasovagal reaction (active reflex including reflex bradycardia and vasodilation) | Prolonged prodromes (dizziness, fatigue, weakness, palpitations, visual and hearing disturbances, hyperidrosis, low back pain, neck or precordial pain) always followed by rapid syncope | Old age Autonomic failure Drug-induced (any vasoactive drug) Comorbidities |
Reflex syncope (VVS) triggered by standing | History of orthostatic stress Tilt table | 3–45min | Initial normal adaptation reflex followed by rapid fall in venous return and vasovagal reaction (active reflex including reflex bradycardia and vasodilation) | Clear prodromes (‘classic’) and triggers always followed by syncope | Young healthy, female dominance |
POTS | Tilt table | Variable | Uncertain: severe deconditioning, inadequate venous return or excessive blood venous pooling advocated | Symptomatic marked heart rate increases (>30bpm) and instability of blood pressure. No syncope | Young female |
| Classification . | Test for diagnosis . | Time from standing to symptoms . | Pathophysiology . | Most frequent symptoms . | Most frequent associated conditions . |
|---|---|---|---|---|---|
Initial OH | Beat-to-beat SBP on lying-to-standing test (active standing) | 0–30s | Mismatch between CO and SVR | Light-headedness/dizziness, visual disturbances a few seconds after standing up (syncope rare) | Young subjects with asthenic habitus Old age, drug-induced (alpha-blockers), carotid sinus syndrome |
Classical OH (classical autonomic failure) | Lying-to-standing test (active standing) or tilt table | 30s–3min | Impaired increase in SVR in autonomic failure resulting in pooling of blood/or severe volume depletion overriding reflex adjustments | Dizziness, presyncope, fatigue, weakness, palpitations, visual and hearing disturbances (syncope rare) | Old age Drug-induced (any vasoactive drug) |
Delayed (progressive) OH | Standing Tilt table | 3–30min | Progressive fall in venous return: low CO, diminished vasoconstriction capacity (failing adaptation reflex), no reflex bradycardia) | Prolonged prodromes (dizziness, fatigue, weakness, palpitations, visual and hearing disturbances, hyperidrosis, low back pain, neck or precordial pain) frequently followed by rapid syncope | Old age Autonomic failure Drug-induced (any vasoactive drug) Comorbidities |
Delayed (progressive) OH + reflex syncope | Tilt table | 3–45min | Progressive fall in venous return (as above) followed by vasovagal reaction (active reflex including reflex bradycardia and vasodilation) | Prolonged prodromes (dizziness, fatigue, weakness, palpitations, visual and hearing disturbances, hyperidrosis, low back pain, neck or precordial pain) always followed by rapid syncope | Old age Autonomic failure Drug-induced (any vasoactive drug) Comorbidities |
Reflex syncope (VVS) triggered by standing | History of orthostatic stress Tilt table | 3–45min | Initial normal adaptation reflex followed by rapid fall in venous return and vasovagal reaction (active reflex including reflex bradycardia and vasodilation) | Clear prodromes (‘classic’) and triggers always followed by syncope | Young healthy, female dominance |
POTS | Tilt table | Variable | Uncertain: severe deconditioning, inadequate venous return or excessive blood venous pooling advocated | Symptomatic marked heart rate increases (>30bpm) and instability of blood pressure. No syncope | Young female |
CO, cardiac output; OH, orthostatic hypotension; POTS, postural orthostatic tachycardia syndrome; SBP, systolic blood pressure; SVR, systemic vascular resistances; VVS, vasovagal syncope.
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