Arrhythmias: Tests, Devices, Physiologists

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ArrhythmiasTests, Devices, Physiologists

• Jane Eldridge
• BSc(Hons) Dunelm, ACP,
• BSc(Hons) Clin. Phys., MRCCPLead Cardiac
  Physiologist Cardiac Catheter Labs
• West Herts NHS Trust

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Tests for Arrhythmias

• ECG, with rhythm strip
• Carotid sinus massage (Hypersensitive carotid
  sinus syndrome)
• 24 hour ECG holter (a.k.a. tape analysis)
• 48 hour to 7 day ECG holter (for less frequent
  symtoms)
• Implanted ECG Loop Recording Device (Reveal for
  very infrequent symptoms)
• Treadmill test for HR response (chronotropic
  incompetence) and exercise-induced arrhythmia
• Echocardiography (structural causes for
  arrhythmia)
• Tilt-testing (pre-syncope / syncope)
• Electrophysiology Study (EPS) for accessory
  pathways and circular or re-entry arrhythmias
  potentially suitable for ablation

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ECGs

• Excellent diagnostic tool
• Non-invasive, quick, easy and cheap!
• Recommend rhythm strip also
• Beware of auto-reporting!
• Good skin prep and electrode contact for clear
  clean ECG
• Essential to have good electrode positioning to
  be useful as a diagnostic tool
• Carotid sinus massage (CSM) to provoke arrhythmia
  eg asystole

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ECG Holters / Tape analysis

• Del-Mar Reynolds Lifecards
• Symptoms button diary
• Each card loaded into specialist tape analyser
  software
• Each 24hr tape takes approx 30 mins to analyse by
  experienced Cardiac Physiologist
• All recorded ECG is examined
• Correlation of symptoms very important
• Report generated by Cardiac Physiologist
• Significant arrhythmias reported immediately to
  Cardiologist

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Implantable ECG Loop Recording Devices (ILRs)
Reveals

• Implanted left pectoral region
• Programmable criteria for auto recording eg brady
  _at_ 30bpm
• Activator given to patient to press if
  symptomatic
• Pt comes into clinic for regular (usually 3
  monthly) downloads of device by Cardiac
  Physiologist
• Can only be downloaded with specialist programmer
• Pt advised to contact dept ASAP if they have an
  event so the device can be downloaded
• Devices cost approx 1250
• Battery lasts for approx 2-3 yrs

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Exercise testing for arrhythmia chronotropic
response

• Looking for appropriate HR response to exercise
  (and any exercise induced arrhythmia)
• Conducted by 2 Cardiac Physiologists (who should
  have ILS or ALS certificate) using treadmill
• Terminated for observed arrhythmia, symptoms or
  poor HR response
• Report generated and printouts of arrhythmias
  observed

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Head-up Tilt Testing for Neurally Mediated Syncope

• Warm, quiet, low lighting room
• Attempt to provoke event. BP and HR closely
  monitored by Cardiac Physiologist (who should
  have ILS or ALS certificate)
• Significant HR drop / sinus pause / asystole
  (cardioinhibitory response) may be suitable for
  pacemaker implant
• For sudden heart rate drops we may use
  specialised algorithms on the pacemaker known as
  accelerations
• Loss of vascular tone with blood pressure drop
  (vasodepressor response) Pacemaker may be
  unsuitable

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Echocardiography to identify structural causes
for arrhythmia

• Non-invasive test that gives vast array of
  information
• Cardiac dimensions
• Cardiac function
• Valve structures
• Valve functions
• Shunts abnormalities
• Cardiomyopathies
• Dysynchrony
• Approx 40 mins per test
• Highly Specialist Cardiac Physiologist required

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Electrophysiology study (EPS)

• Several specialised catheters inserted into
  different areas of the heart
• Electrical activation pattern mapped
• Accessory pathways, circular routes or re-entry
  circuits identified
• Carefully controlled radiofrequency ablation
  across faulty pathways administered by Cardiac
  Physiologist
• Expensive, very specialised equipment and staff,
  time-consuming procedure (2-4hrs)
• Can be curative

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Indications for device implant

• Pacemakers
• SSS, AVB, CHB, CI, Chronic AF with bradycardia,
  Symptomatic Bifasicular block / Trifasicular
  block, Neurally mediated syncope (CSS, VVS,
  situational syncope)
• Biventricular pacemakers (CRT-P)
• CHF with LBBB low EF(lt35), dysynchrony on
  echo, long PR with poor haemodynamics, NYHA class
  IV
• Implantable Cardiac Defibrillators (ICDs)
• Primary indication significant risk of life
  threatening arrhythmia eg Long QT, Brugada, DCM,
  Post MI with NSVT poor EF
• Secondary indication survival of a VT or VF
  arrest
• Biventricular ICD (CRT-D)
• CHF with LBBB low EF(lt35), dysynchrony on
  echo, long PR with poor haemodynamics, NYHA class
  III or IV, prior MI with risk of SCD

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Pacemakers

• Single (atrial or ventricular) or dual chambered
• Pacemakers now store lots of information that can
  be reviewed at follow-up eg time spent in AF
• Now extremely programmable with many features
  algorithms eg (a few examples)
• Rate responsiveness (HR in response to activity)
• AF suppression (pacing the atria)
• Rate drop acceleration response
• Must be regularly followed up in clinic (at least
  once a year) to assess function and battery
• Requires highly specialist equipment and Cardiac
  Physiologists for implant and follow-up
• Device costs vary from approx 1500 to 3500

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Biventricular pacemakers

• Also known as Cardiac Resynchronisation Therapy
  (CRT)
• May be patients for whom chronic RV pacing is
  becoming problematic
• 3 leads usually (atria, RV and LV)
• Pacing both ventricles in a timed manner allowing
  resynchronisation
• Optimises cardiac output by allowing appropriate
  ventricular filling and co-ordinated contraction
• CRT devices cost about 4000 to 8000

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Implantable Cardiac DefibrillatorsICDs

• Ability to DC shock for ventricular
  tachyarrhythmias eg VF and VT
• 700-800 Volts or 30-40 Joules
• Most now can also deliver ATP (anti-tachy pacing)
  to attempt to reduce need for shock therapy
• Extremely complex devices that have many
  programmable features
• Set-up and management is often quite tricky eg in
  the presence of AF
• Most devices are also able to pace although most
  patients do not have a primary pacing indication
• ICD systems cost approx 8,000 to 15,000

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Biventricular ICDs!

• Also known as CRT-D
• 2 ventricular leads for cardiac resynchronisation
• Shock leads for defibrillation
• Highly complex, very programmable devices
• Highly specialist equipment and Cardiac
  Physiologists required
• Devices cost up to 15,000

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Specialist Cardiac Staff

• Cardiographers
• Basic qualifications / certification
• ECGs, application and removal of tapes and
  monitors
• Cardiac Physiologists
• Qualified to BSc (Hons) Clinical Physiology (4
  yrs) or equivalent
• Registered with RCCP (voluntary, soon compulsory)
• ECG analysis interpretation, tape analysis,
  exercise treadmill testing, RACPC, tilt testing,
  cardiac catheterisation intervention
• Highly Specialist Cardiac Physiologists
• Post registration specialisation in echo or
  devices and / or electrophysiology (a further 2-4
  yrs)
• Higher qualifications eg BSE, NASPE or HRUK
  accreditation
• Independent echo reporting, device management
  (implant and follow-up) and or electrophysiology
  study interpretation and treatment

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Guidelines for practice

• National standards for practice
• National Institute of Clinical Excellence (NICE)
• British Cardiovascular Society (BCS) publishes
  guidelines for national standards of practice and
  has affiliations of the following groups
• The Society for Cardiological Science and
  Technology (SCST)
• Registration Council of Clinical Physiologists
  (RCCP)
• British Society of Echocardiography (BSE)
• Heart Rhythm UK (HRUK) for Devices and EP
• Arrhythmia Alliance (AA) for info leaflets
• British Heart Foundation (BHF) for info
  booklets
• Local guidelines and competancies in Cardiology
  Dept

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Any questions?
Old method for taking an ECG!