upright tilt testing

What’s the normal response?

In the heart,

Contractility is increased

HR increases

Vasoconstriction

Maintain cardiac output

Reduction in thoracic Blood Volume (300 – 600ml)

Reduction in filling pressure of the right ventricle

Immediate fall in arterial pressure

Baroreceptors in carotid sinus and aortic arch

Reduced inhibitory drive to the vasometer Canter in the medulla

Increase sympathetic tone, reduce parasympathetic

Maintain cerebral perfusion

Causes of syncope

 Irregularities of heart rate and rhythm
◦ Brady arrhythmias
◦ Varying degrees of heart block
◦ Tachy arrhythmias
◦ Brugada Syndrome / Long QT, ARVC
 Cardiac lesions which obstruct blood flow
◦ Aortic stenosis
◦ HOCM
◦ Pulmonary stenosis
 Reflex-mediated vasomotor instability syndromes
◦ Reflex mechanisms with inappropriate vasodilatation and/or bradycardia
 Differential diagnosis - TIAs, epileptic seizures, hypoglycaemia

• Highly age dependent
  

5 main categories of syncope

• Neurally mediated

  e.g. vasovagal, carotid sinus, situational

• Orthostatic hypotension

  e.g. drug induced, ANS failure

• Cardiac arrhythmia

• Structural cardio-pulmonary

  e.g. HOCM

• Non syncopal

  e.g. metabolic

What tests can assess syncope?

ECG

Echo

Ambulatory ECG, loop recorders

Tilt table test

EP Study

What are the three stages of Neurocardiogenic Syncope?

1. BP and HR increase due to sympathetic tone

2. Abrupt hypotension and bradycardia with symptoms resulting in syncope

3. (Rapid) recovery

Causes of neurocardiogenic syncope

Provoked : -

Prolonged standing

Vigorous exercise in warm environment

Fear

Emotional distress

Severe pain

Blood loss

Patient symptoms and signs (neurocardiogrnic syncope)

• Weakness

• Diaphoresis

• Light headedness

• Headache

• Nausea

  signs are

• Facial pallor

• Yawning

• Pupils dilate

• Nervousness

POTS

What is it?

What happens?

Symptoms?

Postural Orthostatic Tachycardia
Syndrome (POTS)

It is orthostatic intolerance, primarily affects young women

• Insufficient vasoconstriction with increased sympathetic cardiac activation

• Marked increase in heart rate with no change in blood pressure

Symptoms:

• light-headedness, confusion, syncope - occur on standing