Overview
Interpreting Bradyarrhythmia’s
Different types of Bradyarrhythmia’s
Pacemakers
Complex Devices
8
Heart Blocks 1st degree2nd degree
Mobitz Type 1Mobitz Type 22:1, 3:1 AVB
3rd degreeFascicular block - LAD, RAD, TFBLBBB, RBBBAF, Flutter
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 bradycardiaIntermittent – faintness / syncope Persistent – SOB / muscle fatigue / exhaustion
Associated atrial tachyarrhythmias / AV BlockIntermittent – palpitations / faintness / syncope
Persistent – SOB / muscle fatigue / exhaustion
Associated clinical syndromesEmbolicHeart 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
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
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
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
0%
20%
40%
60%
80%
100%
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100+
age by decade
pe
rcen
tag
e o
f to
tal
CHB AF SSS Other
BPEG / HRUK National Database 2003 - 4
Paced Patients: Predominant ECG Indication
0%
20%
40%
60%
80%
100%
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100+
decade
per
cen
tag
e o
f to
tal
syncope pre syncope other
BPEG / HRUK National Database 2003-4
Paced Patients: Predominant Presenting Symptom
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
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 only55% A + V Leads (Dual Chamber) 44% V Lead only (mostly in AF)
V lead normally @ RV apex
A
V
Heart Failure and CRT
Cardiac resynchronization therapy Cardiac resynchronization therapy (CRT)(CRT) Applicable to ~1/3 of all symptomatic HF Applicable to ~1/3 of all symptomatic HF
patientspatients Improvement in long term survivalImprovement in long term survival
NICE indicationsNICE indications NYHA III/IV, Optimal medical therapyNYHA III/IV, Optimal medical therapy LVEF LVEF <<35%35% QRS QRS >> 120ms 120ms
However, 20-30% non responders However, 20-30% non responders to CRTto CRT
Heart failure common and disabling conditionHeart failure common and disabling conditionHeart failure common and disabling conditionHeart failure common and disabling condition
CARE-HF: CRT vs Medical Therapy - Primary End Point
Cleland, J. et al. N Engl J Med 2005;352:1539-1549
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.’