Differential Diagnosis of OI with Excessive Upright tachycardia a - - PowerPoint PPT Presentation

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Aug 05, 2023 594 likes •731 views

Differential Diagnosis of OI with Excessive Upright tachycardia a Physiological Response to Central Hypovolemia? Normal Circulatory Response to Orthostasis Normal Segmental Changes in Normal Segmental Changes in Impedance and volume with

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Differential Diagnosis of OI with Excessive Upright tachycardia

‐ a Physiological Response to Central Hypovolemia?

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Normal Circulatory Response to Orthostasis

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Normal Segmental Changes in Normal Segmental Changes in Impedance and volume with Tilt Impedance and volume with Tilt

200 400 600 800 1000

Time (sec)

10 12 14 16

Impedance (Ohms)

200 400 600 800 1000 Time (sec) 0.70 0.83 0.97 1.10 Fractional Volume Change 200 400 600 800 1000

Time (sec)

14 15 16

Impedance (Ohms)

200 400 600 800 1000 Time (sec) 0.90 1.00 1.10 Fractional Volume Change 200 400 600 800 1000

Time (sec)

20 22 24 26

Impedance (Ohms)

200 400 600 800 1000 Time (sec) 0.90 1.00 1.10 Fractional Volume Change 200 400 600 800 1000

Time (sec)

100 110 120

Impedance (Ohms)

200 400 600 800 1000 Time (sec) 0.90 1.00 1.10 Fractional Volume Change

Thorax

Splanchnic

Pelvic Leg

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Orthostatic Intolerance

The presence of one or more symptoms, e. g., lightheadedness, dizziness, nausea, breathlessness, and vision change, linked specifically to assuming or maintaining upright posture, and symptoms abate once supine Etiology is not a criterion.

Chronic Orthostatic Intolerance

Orthostatic Intolerance for at least 3 months with functional impairment

POTS

Chronic Orthostatic Intolerance with excessive postural tachycardia (at least 40 bpm change within 10 minutes on standardized passive tilt testing) without significant sustained hypotension in the absence of an alternative explanation. If a specific cause is found (e.g. Addison’s Disease) It is no longer called POTS. But the POTS Response is still present.

POTS is a Disease vs POTS is a Physiological Response

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Major Variants of Orthostatic Intolerance Comprise a Differential Dx of POTS

Chronic Bedrest
Initial Orthostatic Hypotension
Orthostatic Hypotension
Chronic Orthostatic Intolerance

Postural Tachycardia Syndrome (POTS) Chronic OI

Postural Vasovagal Syncope/I.S.T.
Any Condition that Promotes Central

Hypovolemia

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Gravitational Deconditioning

Reduced blood volume
Cardiovascular remodeling
Different Regional blood volume redistribution
Reduction in the response to

norepinephrine/MSNA (and other pressors)

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Initial Orthostatic Hypotension

20 40 M A P ( mmH g) 100 200 A rt eri al P ressure ( mmH g) 20 40 M A P ( mmH g) 50 100 150 H eart R at e ( bpm) AP HR 20 40 M A P ( mmH g) 100 200 A rt eri al P ressure ( mmH g) 20 40 M A P ( mmH g) 50 100 150 H eart R at e ( bpm) AP HR

Standing

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Orthostatic Hypotension (OH) is Easy to Understand

Blood pressure falls sufficiently to impair brain blood

flow

Non-neurogenic OH
Hypovolemia or Forced Vasodilation
Neurogenic OH
Autonomic vasoconstrictor failure

due to inadequate release of norepinephrine from sympathetic vasomotor neurons.

100 200 300 400 40 80 120 Arterial Pressure (mmHg) 100 200 300 400 Time (sec) 50 100 150 Heart Rate (bpm)

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Chronic Orthostatic Intolerance: Postural Tachycardia Syndrome (POTS)

Schondorf and Low. Idiopathic postural

rthostatic tachycardia syndrome: an

attenuated form of acute pandysautonomia? Neurology 1995;43:132-137

Day-to-Day Symptoms of OI

+ +

Excessive Tachycardia

(without Hypotension)

Adults Δ>30 or HR>120bpm within 10min Adolescent – Δ>43 (IOH a confound)?

Concurrent Symptoms of OI

during testing

Improved by Recumbence

100 200 300 400 500 600

Time (sec)

30 60 90 120 150

Heart Rate (bpm)

100 200 300 400 500 600

Time (sec)

40 60 80 100 120

MAP (mmHg)

MAP

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What’s This?

120 240 360 480 600 40 60 80 100 120 140 Heart Rate (BPM) 100 200 300 400 500 600 Time (seconds) 50 100 150 Blood Pressure (bpm) Tilt up Tilt down

IOH

HR BP

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Postural Vasovagal Syncope in the Young

Defined by Clinical History

300 600 900 1200 1500

Time (sec)

30 60 90 120 150

Heart Rate (bpm)

300 600 900 1200 1500

Time (sec)

40 60 80 100 120

MAP (mmHg)

Tilt Up Tilt Down

MAP

Slow ↓ BP Rapid

↓

1 2 3

Transient loss of consciousness and postural tone due to global cerebral hypoperfusion and characterized by rapid

nset, short duration, and

spontaneous recovery. Almost always the result

f systemic hypotension

Very Common (~40%)

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