SLIDE 1
1
2
Heart Anatomy
- 4 heart chambers
Medical Systems
Courtesy of Medtronic
Heart & Pacemaker Basics Zhihao Jiang mLab@University of - - PowerPoint PPT Presentation
Heart & Pacemaker Basics Zhihao Jiang mLab@University of - - PowerPoint PPT Presentation
Heart & Pacemaker Basics Zhihao Jiang mLab@University of Pennsylvania 1 Heart Anatomy 4 heart chambers Right Left Atria Ventricles Courtesy of Medtronic Medical Systems 2 Impulse Formation Natural pacemaker: Periodic
SLIDE 2
SLIDE 3
3
Impulse Formation
- Natural pacemaker: Periodic electrical impulses
Medical Systems
SA node
SLIDE 4
4
Atrial Contraction
- Activation Muscle contraction
Medical Systems
Atria
SLIDE 5
5
Delay At AV Node
- Allows the ventricles to fill fully
Medical Systems
AV node
SLIDE 6
6
Ventricular Contraction
- Pump blood out of the heart
Medical Systems
Ventricles
SLIDE 7
7
Bradycardia
- Slow heart rate
Medical Systems
Formation Conduction
SLIDE 8
8
Dual Chamber Pacemaker
- Two leads implanted in right atrium and ventricle
Medical Systems
Pacemaker
SLIDE 9
9
Electrogram (EGM) signals
- Voltage change due to activation
Medical Systems
A V
Pacemaker
SLIDE 10
10
Atrial Sensing (AS)
- Generate sensed event when signal above threshold
Medical Systems
A V
AS
Pacemaker
Pace Threshold
SLIDE 11
11
Ventricular Sense (VS)
- Same for ventricular channel
Medical Systems
A V
AS VS
Pacemaker
Pace
SLIDE 12
12
V-A deadline & Atrial Pacing (AP)
- Pace atrium when no AS within deadline
Medical Systems
A V
V-A
AP AS VS
Pacemaker
Pace
SLIDE 13
13
A-V deadline and Ventricular Pacing (VP)
- Pace ventricle if no VS happen within deadline
Medical Systems
A V
V-A
AP
A-V
VP AS VS
Pacemaker
Pace
SLIDE 14
14
V-V deadline
- Minimum ventricular rate allowed
Medical Systems
A V
V-A
AP
A-V
VP AS VS
Pacemaker
Pace
V-V
SLIDE 15
15
Minimum Ventricular Pacing Interval
- Scheduled VP delayed if time since last ventricular
event (VS, VP) is less than threshold
Medical Systems
A V
V-A
AS
A-V
AS VS
Pacemaker
Pace
V-V
VP
SLIDE 16
16
Minimum interval between Sensed events
- Mimic refractory property of heart tissue
Medical Systems
A V
AS VS
Pacemaker
Pace Noise
ARP VRP
SLIDE 17
17
Post-Ventricular Atrial Blocking period (PVAB)
- Preventing crosstalk between A and V channels
Medical Systems
A V
AP VP AS VS
Pacemaker
Pace Threshold
PVAB
SLIDE 18
18
Single Chamber Mode
- Maintain ventricular rate
Medical Systems
V
VP VS
Pacemaker
Pace
VRP
V-V
SLIDE 19
19
Pacemaker Mediated Tachycardia (PMT)
- Pacemaker inappropriately increases ventricular rate
– Normal ventricular rate without pacemaker – Ventricular Tachycardia with pacemaker
- Two cases
– Atrial Tachycardia Response – Endless Loop Tachycardia (ELT)
Medical CPS
SLIDE 20
20
Atrial Tachycardia Response: Open-loop
- Atrial Tachycardia: Abnormally fast atrial rate
Medical Systems
A V
SLIDE 21
21
Atrial Tachycardia Response: Open-loop
- AV node enters Refractory period
Medical Systems
A V
AV node Refractory
SLIDE 22
22
Atrial Tachycardia Response: Open-loop
- Another early atrial contraction
Medical Systems
A V
AV node Refractory
SLIDE 23
23
Atrial Tachycardia Response: Open-loop
- Blocked by AV node during refractory
Medical Systems
A V
AV node Refractory
SLIDE 24
24
Atrial Tachycardia Response: Open-loop
- Third atrial contraction
Medical Systems
A V
AV node Refractory
SLIDE 25
25
Atrial Tachycardia Response: Open-loop
- Blocked by AV node again
Medical Systems
A V
AV node Refractory
SLIDE 26
26
Atrial Tachycardia Response: Open-loop
- AV node refractory finished
Medical Systems
A V
AV node Refractory Finished
SLIDE 27
27
Atrial Tachycardia Response: Open-loop
- 3:1 A-V conduction
Medical Systems
A V
SLIDE 28
28
Atrial Tachycardia Response: Open-loop
- Normal Ventricular rate in contrast to fast atrial rate
Medical Systems
A V
Within safe region
SLIDE 29
29
Atrial Tachycardia Response: Closed-loop
- Inappropriately increase ventricular rate
Medical Systems
AS
Pacemaker
Pace A V
SLIDE 30
30
Atrial Tachycardia Response: Closed-loop
- Mimic refractory property of heart tissue
Medical Systems
AS
Pacemaker
Pace A V
AV node Refractory
SLIDE 31
31
Atrial Tachycardia Response: Closed-loop
- Some of the fast atrial events are filtered
Medical Systems
AS
Pacemaker
Pace
ARP
A V
[AR] AV node Refractory
SLIDE 32
32
Atrial Tachycardia Response: Closed-loop
- VP when AV node in Refractory
- AV node function bypassed
Medical Systems
AS VP
Pacemaker
Pace A V
[AR]
A-V
AV node Refractory
SLIDE 33
33
Atrial Tachycardia Response: Closed-loop
- Ventricular rate at Upper Rate Limit
Medical Systems
AS VP
Pacemaker
Pace A V
[AR] AS [AR] VP At URL
A-V A-V
SLIDE 34
34
Endless Loop Tachycardia (ELT): Closed-loop
- Pre-mature Ventricular Contraction (PVC)
Medical Systems
AS VP
Pacemaker
Pace A V
A-V
VS PVC
SLIDE 35
35
Endless Loop Tachycardia (ELT): Closed-loop
- Retrograde conduction causing atrial contraction
Medical Systems
AS VP
Pacemaker
Pace A V
A-V
VS Retrograde conduction AS
V-A
SLIDE 36
36
Endless Loop Tachycardia (ELT): Closed-loop
- VP after A-V deadline
Medical Systems
AS VP
Pacemaker
Pace A V
A-V
VS AS
V-A
VP
A-V
SLIDE 37
37
Endless Loop Tachycardia (ELT): Closed-loop
- The VP-AS-VP pattern persists, causing ELT
Medical Systems
AS VP
Pacemaker
Pace A V
A-V
VS AS
V-A
VP
A-V
AS
V-A
VP
A-V