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TILT TESTING INFORMATION AND PROTOCOLS

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					       TILT TESTING
INFORMATION AND PROTOCOLS

   For technicians and doctors

               Jan 2010




               Dr Nicola Cooper
       Clinical Lead for Acute Medicine
                                 TILT TESTING

This information has been compiled for technicians and doctors working in the
tilt testing service at the Leeds Teaching Hospitals NHS Trust.

Overview

       Introduction to tilt testing
       Indications
       Contraindications
       The Leeds tilt test protocol
       Responses to tilt testing
       Writing the report
       Carotid sinus massage in the tilt lab
       Autonomic function tests in the tilt lab
       Referrals
       Further resources and contacts

Introduction to tilt testing

Tilt testing is used to investigate syncope (pronounced sin-cope-ee). Syncope
comes from the Greek „to interrupt‟ and it is a common medical problem.
Syncope occurs when there is transient global cerebral hypoperfusion (in
other words, not enough blood to the brain). This can be either due to low
blood pressure or a heart problem.

In Leeds we follow the European Society of Cardiology guidelines on the
investigation and management of syncope. These can be found at
www.escardio.org/knowledge/guidelines/

In a nutshell, when a person presents with one or more „blackouts‟, the main
way to diagnose the problem is by a careful history. The history (including an
eye-witness account) is everything! The ESC guidelines say that the initial
evaluation should include:

       History
       Examination (of the neurological and cardiovascular system in
       particular)
       12-lead ECG
       Lying and standing blood pressure

In a significant proportion of patients, the diagnosis will be obvious after the
initial evaluation (especially if an experienced clinician has done it) and no
tests are needed.

If the person has no structural heart disease (ie no cardiac history, no
murmurs and a normal ECG - and in young people no family history of sudden
cardiac death), and there are no “red flags” in the history, then the chances of




                                                                                   2
syncope being due to a cardiac arrhythmia are slim. In one study, a normal
ECG virtually excluded an arrhythmia as the cause of syncope.
Tilt testing is used as a first line test in unexplained syncope when a cardiac
arrhythmia is unlikely. In the over 50‟s carotid sinus massage may be
indicated as well.

Tilt testing is also used when the diagnosis is suspected, but it would be
helpful to „prove‟ it in certain patients.

There are 4 main types of syncope:

       Neurally mediated
       Orthostatic (postural) hypotension or „OH‟
       Cardiac arrhythmias
       „Structural‟ eg aortic stenosis or HOCM

By far the most common cause of syncope is neurally mediated. Cardiac
arrhythmias account for around 20% of all syncope. In older people, low blood
pressure and orthostatic hypotension are much more common than neurally
medicated syncope.

What is „neurally mediated syncope‟? The term refers to a fainting reflex which
is triggered in certain people. Neurally mediated syncope includes vasovagal
syncope (normal fainting), situational syncope (people who faint in certain
situations eg unpleasant stimuli) and carotid sinus hypersensitivity.

Orthostatic hypotension is when the blood pressure falls immediately on
standing, due to impaired autonomic reflexes. It is common in old people,
often exacerbated by drugs, or can be due to diseases eg diabetes.

There is another common pattern in older people, often termed the „elderly
dysautonomic pattern‟ - this is a slow fall in BP after standing which goes
undetected on normal lying and standing BPs. Older people with this problem
commonly faint without typical warning symptoms.

The next page has a summary diagram of the ESC guidelines on the
investigation of syncope. Technicians and doctors are encouraged to read the
full guideline.




                                                                                  3
     Summary of the ESC guidelines


                                                               No
                                   Is it syncope?
                              (The history may suggest                    Other
                                 another diagnosis).                      treatment


                                               Yes


                                     Initial evaluation




Obvious diagnosis in             Suspected diagnosis                Unexplained syncope
a large proportion of
   patients - treat.



                 Cardiac syncope          Neurally                  Unexplained means
                 likely - do              mediated                  after evaluation by
                 relevant heart           syncope likely -          an expert clinician.
                 tests eg monitor,        do tilt test + CSM        Investigate only if
                 Echo, Reveal             (autonomic                recurrent or single
                 device,                  function tests            but serious (eg
                 electrophysiology        where relevant)           injury or whilst
                 etc                                                driving) - do neurally
                                                                    mediated syncope
                                                                    tests first.



                                             Treat any diagnosis.
                  If the initial tests are all negative, re-evaluate the patient and think
                                          about other syncope tests.



     CSM = carotid sinus massage.




                                                                                        4
Indications

Indications for tilt testing are described in the diagram above. In addition, tilt
testing is sometimes useful for:

       Differentiating syncope with myoclonic jerks from seizures
       Evaluating patients with unexplained falls (which are often due to brief
       syncope)
       Assessing recurrent pre-syncope symptoms
       Demonstrating the benign nature of the condition to patients who need
       reassurance about their syncope
       When the particular cardiovascular response during syncope may be
       useful in deciding treatment

Contraindications

Contraindications to tilt testing include:

       Patient refusal
       Morbid obesity (table has a maximum weight)
       Unable to stand for long periods due to pain
       Pregnancy
       Recent (within 6 months) myocardial infarction or stroke/TIA
       A known tight stenosis anywhere (eg heart valve, LV outflow
       obstruction, coronary or carotid/cerebrovascular artery)

In atrial fibrillation, the accuracy of beat-to-beat blood pressure monitoring
may be impaired and this should be taken in to account when considering a tilt
test.

In Leeds we do not provide a tilt test service for patients under the age of 16.

We have now switched from using lower body negative pressure (LBNP) tilt
testing to GTN spray provocation and follow the „Italian Protocol‟ – see
references at the end.




                                                                                     5
Leeds tilt testing protocol (Italian Protocol)


   1. The patient should fast for 2 hours before the test.

   2. There is no need to re-take the patient‟s history if they have been seen
      by an expert clinician and the history is fully documented in the clinic
      /referral letter.

   3. Ensure the patient is not wearing any support stockings and has
      emptied their bladder before the test.

   4. Perform the test in a quiet room with dim lighting.

   5. Do not insert a cannula. This affects the results of the test, and is not
      necessary for GTN provocation tilt tests.

   6. Lay the patient supine (flat) for 5 minutes, after monitoring equipment
      has been attached.

   7. Head up tilt (between 60-70o) for 20 minutes.

   8. If no end points are reached, administer 1 squirt (400mcg dose) of
      sublingual GTN spray while the patient is still upright.

   9. Continue the head up tilt for another 15 minutes.

   10. The test ends if:

          a. Time is completed (ie 20 + 15 minutes head up tilt)

          b. Syncope occurs

          c. There is progressive symptomatic orthostatic hypotension

          d. There is progressive symptomatic fall in heart rate (to <40/min)

          e. Asystole occurs

          f. Arrhythmia or tachycardia >170/min

          g. Patient distress or discomfort.


Monitoring during the test

      Continuous non-invasive beat-to-beat BP (Nexfin®)
      Intermittent non-invasive BP using a cuff every 2 minutes
      Continuous 3-lead ECG
      Continuous end-tidal CO2 (capnograph)


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The reproducibility of an initial negative tilt test response is 85-94%, but the
reproducibility of an initial positive response to tilt testing is 31-92%. People‟s
physiological responses to tilt testing can vary, so the test is limited in its
ability to assess the effectiveness of different treatments for syncope.

Complications of tilt testing

Asystole of several seconds has been reported during tilt testing, but it cannot
be considered a „complication‟ because it is an end-point of the test. No
deaths have ever been reported in the literature. If the patient is laid flat
quickly (sometimes with their legs elevated) they will recover.

No complications due to GTN provocation have been published. A mild
headache is relatively common after GTN spray. Rarely transient AF after a
positive tilt test has been reported.

Tilt testing is a low risk procedure. The patient should be supervised at all
times by a nurse or technician. A doctor does not need to be present in the
same room for the test, but a named doctor should be available nearby in
case of any queries or complications.

A crash trolley and resuscitation equipment should be available in the same
room as the tilt test in case of the rare occurrence of arrhythmias.

Responses to tilt testing

A „positive‟ tilt test is when the patient‟s syncopal or pre-syncopal symptoms
are reproduced and accompanied by hypotension, bradycardia (relative or
otherwise) or both. Heart rate and blood pressure changes in isolation should
not prompt a diagnosis of neurally mediated or OH related syncope. (However
- in elderly patients this often does not apply as they tend to get few warning
symptoms).

Anyone can faint during a tilt test. Just because the test is positive does not
mean that is the reason for a person‟s blackouts. In the same way, sometimes
a person with neurally mediated syncope may have a negative tilt test. This is
because there is no such thing as a perfect test. All tests have something
called a „sensitivity‟ (ability to pick up true diagnoses) and a „specificity‟ (ability
to rule out non-diagnoses).

Therefore a tilt test must always be interpreted in the light of the clinical
evaluation. The interpretation of the tilt test and treatment plan afterwards is
the responsibility of the referring doctor (as is advice about driving). However,
the technician‟s report is key to understanding what the tilt test result means
for the patient.




                                                                                      7
There are several different possible positive responses to a tilt test. The same
patient may have different responses at different times:

       Vasodepressor - the blood pressure falls but the heart rate does not fall
       by more than 10% from its peak.
       Cardio-inhibitory type A or „cardio-inhibition without asystole‟ - the heart
       rate falls to less than 40 /min for more than 10 seconds but asystole of
       more than 3 seconds does not occur.
       Cardio-inhibitory type B or „cardio-inhibition with asystole‟ - there is
       asystole of more than 3 seconds.
       Mixed - a mixture of a vasodepressor response and cardio-inhibitory
       type A response.
       Excessive heart rate rise - a heart rate that rises both at the onset of
       upright position and throughout its duration before syncope (greater
       than 130 /min). This is known as POTS (postural orthostatic
       tachycardia syndrome) and more can be read about this in the further
       resources.

„Chronotropic incompetence‟ is another response in which there is no heart
rate rise during the tilt test (ie less than 10% from baseline).

Diagnostic criteria for POTS

The symptoms of POTS differ to that of vasovagal syncope in that postural
dizziness predominates (often disabling), and patients often report palpitations
and fatigue. There is no significant drop in postural blood pressure. Only 30%
of patients experience syncope.

Diagnostic criteria are:

       An increase in HR by > 30/min or to > 120/min within 5-30 minutes of
       standing
       Associated symptoms of orthostatic intolerance, relieved by
       recumbency
       Absence of orthostatic hypotension (ie fall in BP of >20/10 mmHg on
       standing)
       Absence of anaemia, dehydration, hyperthyroidism
       Absence of medications that impair autonomic regulation (eg
       vasodilators, diuretics, antidepressants)

Clinicians may also want to exclude phaeochromocytoma as part of the
diagnostic work-up for POTS.

Pathophysiological sub-types have been identified, which probably co-exist to
a varying degree in each individual. Ideally, patients with POTS should be
referred to a Consultant with an interest in this condition.




                                                                                 8
Psychogenic non-epileptic seizures

Typical responses are seen during tilt testing in patients with psychogenic
non-epileptic seizures. Patients are usually younger women, with a high
chance of having symptoms during the tilt test. A sudden increase in heart
rate and blood pressure, following by atypical unresponsiveness and jerking is
characteristic. A detailed description is extremely helpful to the referring
clinician (see further resources).

Writing the report

The technician‟s report is key in the further management of the patient. It
should include the information as outlined on the tilt test service report sheet
(see next page). Key bits of information here are:

       The baseline BP and heart rate
       The change in BP and heart rate
       What the BP and heart rate was when the test was stopped
       Which tilt test end points (above) were reached

However, one of the most important parts of the report is the free text
observations of the technician supervising the test. Key bits of information
here are:

       Whether the cardiac reflex response to head-up tilt was normal or not
       (see below*)
       At what point in the test the patient developed any symptoms
       If the patient did develop symptoms, are these the same as his or her
       usual symptoms before a blackout (the patient should be asked this at
       the end of the test)
       Whether there was hyperventilation or severe anxiety during the test
       If the patient had a „blackout‟ during the test but the blood pressure and
       heart rate were normal, a detailed description of what happened is
       extremely useful (as this could be psychogenic syncope)

*The normal response when a person moves from supine to upright during a
tilt test is for the heart rate to increase and the blood pressure to remain the
same. Some people with blunted autonomic responses (or those who are
paced) will not demonstrate an increase in heart rate, and this is useful to
document. In older people there may be a transient drop in blood pressure on
head-up tilt which recovers back to normal within seconds. This „immediate
postural hypotension‟ would be missed on manual BP monitoring and is
important to document.

The free text observations are useful as a summary of what happened during
the test.

The next page shows the tilt test service report sheet, with the key bits of
information used to make a diagnosis highlighted.



                                                                                   9
               LEEDS TEACHING HOSPITALS NHS TRUST
                                                                                Patient:
                NHS                                                             Address:


               Tilt Test Service                                                DOB:
               Cardio-Respiratory Unit                                          Hospital no:
               1st Floor Chancellor Wing                                        NHS no:
               St James’s University Hospital
               Phone: 0113 2065930 / 2064482
               Fax: 0113 2065587

                                                TILT TEST REPORT
               Test(s) performed:

               Test date:                                                 Referrer‟s location:    The tilt test service takes
                                                                                                  external referrals which
               Referring consultant:                                      Billing category:       it bills for.

               Italian Protocol: head-up tilt for 20 mins then GTN provocation and head-up tilt for 15 mins.


               Response to head-up tilt alone
               (nb - please see enclosed BP and heart rate record)

                                    Supine            (predicted)          Change                (predicted)
               Heart rate
               Systolic BP
               Diastolic BP


               Response to head-up tilt and lower body negative pressure (LNBP)

               Time to stop test                               mins
               Reason for stopping test
Describe       Symptoms
which of the
test end-      Max heart rate                                 bpm
points were    Heart rate at end of test                      bpm
reached.       BP at end of test                             mmHg


               Technician’s report below                                  Technician’s name:


                                    This part is very               What symptoms the patient
                                    important. The                  had, if any, and whether he or
                                    referrer needs to               she says these are the same
                                    know what the heart             as in their usual collapses.
                                    rate and BP was
                                    when the decision
                                    was taken to stop
                                    the test.


               The Nexfin® printout + narrative report + hand-written observations (including
               capnograph results) are also enclosed with this report.


                                                                                                               10
Carotid sinus massage in the tilt lab

Carotid sinus hypersensitivity (CSH) is a condition found in the over 40‟s,
especially men. The carotid body is located at the site of the carotid artery
bifurcation in the neck. Pressure at this site causes a reflex slowing of the
heart rate and fall in blood pressure. In people with CSH, this reflex is
“hypersensitive”, and causes syncope - usually without a warning. Only rarely
is there a history of syncope on head turning which gives a clue as to the
condition.

Carotid sinus massage (CSM) is therefore sometimes indicated as a test in
syncope or unexplained falls (which are actually brief syncope). It may be
requested in patients at the same time as a tilt test “unless the tilt test is
positive” (by which the referring clinician means and fall in BP and/or heart
rate in response to head-up tilt with associated symptoms). CSM should be
performed by a doctor who will double-check any contraindications, explain
the procedure again to the patient and deal with any potential complications.

The informed consent for CSM, including an explanation of the potential
complications, is the responsibility of the referring clinician. The referring
clinician should also ensure that there are no contraindications to the
procedure and this should be documented in the notes and/or referral letter.
This is because the doctor present in the tilt lab will usually be a registrar who
does not know the patient. When in doubt, the registrar should seek advice
from either the referring clinician or the designated supervising consultant in
the nearby clinic.

CSM is ideally performed in the tilt lab because in at least 30% of cases, a
positive response is only present in the upright position. Furthermore, the
blood pressure response is important to document, as some people get a
transient significant fall in BP without a significant fall in heart rate. This can
only be picked up by the beat-to-beat BP monitor (Nexfin®) in the tilt lab.

Indications for CSM

CSM is indicated in patients over the age of 40 with syncope or unexplained
falls in which the history, clinical examination and relevant cardiology and
neurology tests have not clearly identified a cause of the symptoms.

Contraindications to CSM

The contraindications to CSM are:

       Patient refusal
       Morbid obesity (table has a maximum weight)
       Recent (within 6 months) myocardial infarction or stroke/TIA
       Any previous adverse reaction to CSM
       Previous VF or VT
       A carotid stenosis of 50% or more (or a known tight stenosis elsewhere
       as in the contraindications for tilt testing)


                                                                                      11
The referring clinician is responsible for listening to the carotids to detect any
bruit before requesting the test. If a carotid bruit is present then carotid
Doppler ultrasonography should be performed prior to CSM. (It is known that
the presence of a bruit does not correlate with the severity of any carotid
stenosis, but this is the safe and pragmatic approach to practice that UK
syncope services take).

Potential complications of CSM

Complications of CSM are rare. The main complication is transient
neurological signs (TIA) or stroke. Studies report complication rates of
between 0.17 and 0.45% - ie “around 1 in 1000”.

If neurological signs develop the patient should be laid flat immediately and
measures taken to rapidly restore the blood pressure to normal. Aspirin
300mg should be given if not contraindicated and the patient should be
admitted to the Acute Medical Unit in Chancellors Wing. Contact one of the
Acute Medicine Consultants if there are any obstructions.

More rarely, CSM can give rise to transient atrial fibrillation. VT or VF never
occurred in 16,000 CSMs in one study.

How to do CSM

CSM should be performed by a clinician who knows how to manage the
potential complications.

       The patient lays supine for 5 minutes after the monitoring equipment is
       attached. Do not insert a cannula.
       Still supine, the right side is massaged first (as up to 66% of subjects
       are positive on this side)
       CSM is performed at the site of maximal pulsation over the carotid
       sinus, which is located between the thyroid cartilage and the angle of
       the mandible
       Using the middle three fingers, firm pressure is applied and the sinus is
       massaged longitudinally for 5 seconds
       Massage should be discontinued if asystole of more than 3 seconds
       occurs or the patient gets syncope

The following monitoring is carried out during the test:

       Continuous non-invasive beat-to-beat blood pressure
       Continuous 3-lead ECG, capable of printing during CSM
       Intermittent blood pressure (either Dynamap or manual) at the start of
       the test to “calibrate” with the Nexfin® monitor

If there is no significant change in BP or heart rate (see below) and no
symptoms, then the left side is massaged supine. If supine CSM is negative
on both sides then the procedure is repeated with the patient tilted upright at


                                                                                  12
60-70o, again starting with the right side. At least 60 seconds should be left
between each massage.

If at any time CSM is positive then the procedure is terminated and the patient
laid flat.

After CSM the patient should lay flat for at least 10 minutes, which reduces
the likelihood of neurological complications.

Responses to CSM

Carotid sinus hypersensitivity is diagnosed when CSM produces:

       More than 3 seconds asystole (cardio-inhibitory type)
       More than 50 mmHg fall in systolic BP (vasodepressor type)
       Both of the above (mixed type)
       And the patient has symptoms (dizziness or syncope)

Recurrent syncope due to cardio-inhibitory carotid sinus hypersensitivity - in
the absence of drugs which depress the sinus node or AV node conduction -
is an indication for a dual chamber pacemaker.

The heart rate response to CSM occurs immediately, but the BP response is
maximal at 18 seconds after the start of CSM, returning to baseline at 30
seconds. The BP response is important to document.

The results of CSM are documented as free text, enclosing the printout of the
3-lead ECG, with arrows to indicate the start of right or left, supine or upright
CSM.

Autonomic function tests in the tilt lab

Autonomic function tests are sometimes requested for patients who may have
autonomic neuropathy. This condition causes often profound postural
hypotension.

There are 3 parts to the autonomic function test provided by the tilt test
service:

   1. Valsalva manoeuvre
   2. Measurement of heart rate variability
   3. Active stand test (lying to standing BP)

Valsalva manoeuvre

The Valsalva manoeuvre is used to test whether a patient has a normal
autonomic response. It need only be performed once if clear measurements
are obtained.




                                                                                 13
       The patient (sitting) is asked to blow in to the outer part of a 20 ml
       syringe attached to a mercury sphygmanometer
       He or she should blow so that the mercury is at 40 mmHg for 10
       seconds
       The BP and heart rate response is monitored during the test and for 45
       seconds afterwards

The normal physiological response to a Valsalva manoeuvre consists of 4
phases, which are marked on the figure below:




During strain there is a fall in BP and rise in HR. After strain there is a rise in
BP and fall in HR. In autonomic neuropathy this pattern) does not occur.

The best way to report the response to a Valsalva manoeuvre is to use the
printout facility of the Nexfin® and mark the start and end of the exhalation.
Autonomic function tests are only rarely requested in the tilt lab and
interpretation should be left to the referring clinician.

Measurement of heart rate variability

A rhythm strip is recorded while the patient breathes deeply in (for 5 seconds)
and out (for 5 seconds). Each breath in and out is marked on the rhythm strip,
which is recorded for 1 minute.

The longest R-R interval during inspiration and the shortest R-R interval
during expiration is documented. An abnormal response is that there will be
no heart rate variability.




                                                                                  14
Active stand test (lying to standing BP)

This is a simple lying and standing blood pressure test using the non-invasive
beat-to-beat BP monitor (Nexfin®). It is more useful in evaluating symptoms of
postural (orthostatic) hypotension than the tilt test because we want to assess
the patient with his or her active muscle involvement during standing (the
reasons for this are complex!)

During an active standing test:

       The patient lays supine for 5 minutes and the monitoring equipment is
       attached
       The patient stands on the floor
       The BP and heart rate response is monitored
       The test ends after 3 minutes of standing

The supine BP and heart rate is documented, then immediately upright, then
every 30 seconds until 3 minutes has elapsed. Orthostatic hypotension is
defined as a fall in systolic BP of at least 20 mmHg and/or diastolic BP of at
least 10 mmHg within 3 minutes of standing. The lowest systolic BP in the
upright position should be recorded.

In some patients the BP can change rapidly, which is why the Nexfin® is
used. Some patients have a significant immediate drop in BP which recovers
very quickly and this is also important to document.

Referrals

The referral form for tilt testing can be found on the cardiology Intranet site.
This form should be accompanied by a letter or a description of the patient‟s
symptoms so that referrals can be screened by a consultant physician if the
service requires this. Patients will not be booked unless a referral form has
been filled in.




                                                                               15
Further resources and contacts

For further reading and resources, please see the list below. Consultants with
a special interest in syncope include Dr Nicola Cooper and Dr Shona
McIntosh (older people). Dr Greg Reynolds is the clinical director for
cardiology, including the tilt test service.

      Benditt DG, Blanc JJ, Brignole M and Sutton R. The evaluation and
      treatment of syncope. A handbook for clinical practice. 2nd Edition. Eur
      Soc of Cardiology. Wiley-Blackwell, Oxford, 2006. (Would be worth
      getting a copy of this for the tilt test lab as this is the main syncope
      textbook).
      www.escardio.org/knowledge/guidelines/ (The European Society of
      Cardiology guidelines on the investigation and management of
      syncope).
      Kenny RA, O‟Shea D, Parry SW. The Newcastle protocols for head-up
      tilt table testing in the diagnosis of vasovagal syncope, carotid sinus
      hypersensitivity and related disorders. Heart 2000: 83; 564-69
      Parry SW and Kenny RA. Tilt table testing in the diagnosis of
      unexplained syncope. Q J Med 1999; 92: 623-29
      Bartoletti A, Alboni P, Ammirati F et al. „The Italian Protocol‟: a
      simplified head-up tilt testing potentiated with oral nitroglycerin to
      assess patients with unexplained syncope. Europace 2000: 2; 339-42
      Heaps T and Cooper N. A case of postural orthostatic tachycardia
      syndrome on the Acute Medical Unit. Acute Medicine 2009; 8(1): 29-
      21. www.rila.co.uk
      Zaidi A, Crampton S, Clough P et al. Head up tilt testing is a useful
      provocative test for psychogenic non-epileptic seizures. Seizure 1999;
      8: 353–355
      McIntosh SJ and Kenny RA. Carotid sinus syndrome in the elderly. Jou
      Royal Soc Med 1994: 87; 798-800




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