Transcript Bradyarrhythmia Pacing Devices

Bradyarrhythmia’s,
Pacemaker’s
& Complex Devices
Dr Chris McAloon
Medical Student Teaching
Overview
Interpreting
Bradyarrhythmia’s
Different types of
Bradyarrhythmia’s
Pacemakers
Complex Devices
First Rule
“ Always look at the patient”
Conducting system
Heart Blocks
NSR
Sinus brady
SSS
Sinoatrial block
Sinus arrest
7
Heart Blocks
1st degree
2nd degree
Mobitz Type 1
Mobitz Type 2
2:1, 3:1 AVB
3rd degree
Fascicular block - LAD, RAD, TFB
LBBB, RBBB
AF, Flutter
8
Reversible Causes of Slow Heart Rate
Drug therapy
Acute Myocardial Infarction
Hypothermia
Hypothyroidism
Athletic Heart
Vaso-vagal mechanisms
Complete AV Block
 All patients with persistent or intermittent complete AV
block should be paced unless there is a reversible cause
Irrespective of symptoms
 Reversible causes include recent inferior MI,
 hypothyroidism and drugs
 This includes patients with congenital CHB
 If you are not going to pace, you really need to be able
to justify that decision
Sinus Node Dysfunction
 Inappropriate bradycardia
Intermittent – faintness / syncope
Persistent – SOB / muscle fatigue / exhaustion
 Associated atrial tachyarrhythmias / AV Block
Intermittent – palpitations / faintness / syncope
Persistent – SOB / muscle fatigue / exhaustion
 Associated clinical syndromes
Embolic
Heart Failure
The ‘ALS’ Approach
1. Is there electrical activity?
2. What is the ventricular (QRS) rate?
3. Is the QRS rhythm regular or
irregular?
4. Is the QRS complex width normal
or prolonged?
5. Is there atrial activity present?
6. Is the atrial activity related to
ventricular activity, if so how?
The Heart Block System
1. Are the P waves associated with
the QRS complex at all?
No = This is 3rd Degree Heart Block
Yes= Move to Question 2
Third Degree/ Complete Heart Block
The Heart Block System
2. Is there one P wave to one QRS,
with a prolonged PR interval
that is not progressing (in
length)?
Yes= This is 1st Degree Heart block
No = Go to question 3
First Degree Heart Block
The Heart Block System
3. Is there progression in PR
interval duration until there is
a non-conducted P wave?
Yes= This is Wenckebach
No = Go to question 4
Mobitz Type 1/ Wenckebach
The Heart Block System
4. Therefore it must be Mobitz type 2
 Mobitz type 2 difficult to explain
 P waves conducted normal PR interval
 There are P waves that are not conducted
 Not always a specific block
 2:1
 3:1
 4:3
Mobitz Type 2
Mobitz 2 – 3:1 Block
SA
Slow Sinus Rate
Atrial
Tachy-arrhythmias
AV Block
Pacemaker’s
Pacing Indications
Paced Patients: Predominant ECG Indication
CHB
AF
SSS
Other
percentage of total
100%
80%
60%
40%
20%
0%
0-9
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100+
age by decade
BPEG / HRUK National Database 2003 - 4
Paced Patients: Predominant Presenting Symptom
syncope
pre syncope
other
percentage of total
100%
80%
60%
40%
20%
0%
0-9
10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100+
decade
BPEG / HRUK National Database 2003-4
Pacing Indications
 AV Block
Complete Heart Block
Second degree AV block (High block or
symptoms)
Reversible: Inferior MI, Hypothyroidism
 Sinus Node Disease
Chronotropic Incompetence
If resting HR in day time <30
 Atrial Fibrillation
Bradycardia
Bradycardia in presence drugs for
uncontrolled Tachycardia
International Codes Pacemaker
First Letter = Chamber(s) being PACED (A,V,D)
Second Letter = Chamber(s) being SENSED
Third Letter= How the device RESPONDS to
SENSED Event (Inhibits, Triggers, Dual (I+T))
Fourth Letter = Added feature e.g R = Rate Response
Pacemaker Basic’s
A Unipolar System
A Bipolar System
What is the PPM?
What is the PPM?
What is the PPM?
What is the PPM?
Electrodes -- Fixation Mechanism
 Passive Fixation Mechanism – Endocardial
 Tined
 Finned
 Canted/curved
Electrodes – Fixation Mechanism
 Active Fixation Mechanism – Endocardial
 Fixed screw
 Extendible/retractable
Pacemaker Prescription
Re-establish stable heart rate
Restore AV synchrony
Achieve chronotropic competence
Achieve normal physiological activation
and timing
A lead if normal A function
V lead if actual / threatened AV HB
Rate modulation if slow
1% A Lead only
55% A + V Leads (Dual Chamber)
44% V Lead only (mostly in AF)
A
V
V lead normally @ RV apex
Complex Devices
Complex Devices
What can be done?
What can be done?
Technology
Heart Failure and CRT
Heart failure common and disabling condition

Cardiac resynchronization
therapy (CRT)



NICE indications




Applicable to ~1/3 of all symptomatic
HF patients
Improvement in long term survival
NYHA III/IV, Optimal medical therapy
LVEF <35%
QRS > 120ms
However, 20-30% non
responders to CRT
CARE-HF: CRT vs Medical Therapy - Primary End Point
Cleland, J. et al. N Engl J Med 2005;352:1539-1549
NICE Guidance 95 & 120
Global Heroes 2012: 10 mile run
 Susan Filler was an avid runner
 2007 survived Cardiac Arrest
 ARVD diagnosed & ICD implanted
 Completed Boise & Canada Ironman
 Patrick Grayson 21
 Long QT diagnosed at 11
 At 12 Cardiac Arrest & ICD implanted
 Protection of ICD gave confidence to run
 February 2012 ran 1st marathon
 Erin Clark
 20 years ago SCA, diagnosed Long QT
 BB 1st, then implanted ICD.
 ICD gave confidence to be active as protection
 1 year ago started running
What patients say about ICD
 When I die will this keep shocking me? In my
coffin?
 One day I want to join my wife – how can I
do that with an ICD?
 Can I be comfortable at the end of my life?
 Will Deactivation hurt? Do I need surgery?
 Will I die immediately after the ICD is
deactivated?
 I feel like the bionic man – can I die with
this?
ESC GUIDANCE 2010
 ‘It seems clear at this point that this device is in your best interest, but
you should know at some point if you become very ill from your heart
disease or another process you developing the future, the burden of this
device may outweigh its benefit. While that point is hopefully a long way
off, you should know that turning off your defibrillator is an option.’
 ‘Now that we’ve established that you would not want resuscitation in the
event your heart was to go into an abnormal pattern of beating, we should
reconsider the role of yourdevice. In many ways it is also a form of
resuscitation. Tell me your understanding of the device and let’s talk about
how it fits into the larger goals for your medical care at this point.’
 ‘Clinicians may be concerned that withdrawing life-sustaining treatments
such as CIED (ICD) therapies amounts to assisted suicide or euthanasia.
However, two factors differentiate withdrawal of an unwanted therapy
from assisted suicide and euthanasia: the intent of the clinician, and the
cause of death. First, in withdrawing an unwanted therapy, the clinician’s
intent is not to hasten the patient’s death, but rather, to remove a
treatment that is perceived by the patient as a burden.’