Transcript SPECIAL SITUATIONS, TROUBLE

Heart Rhythm Refresher Course 2014
Sudden Cardiac Death, Ventricular Arrhythmias
and ICD Therapy
ICD Implantation:
Techniques and Trouble-shooting
Dr Chan Kwok Keung
Department of Medicine
PYNEH, Hong Kong
6 Apr 2014
ICD Implantation:
Techniques and Trouble-shooting
1.
ICD implantation procedure (briefly on the
standard procedure)
2.
Special situations, trouble-shooting and
management

Venous access and lead placement

What is Current of Injury (COI)?

Defibrillation threshold (DFT) testing
ICD: Conception 1966
Dr Mirowski
ICD: Conception 1966
Over-the-counter electronic components
ICD: First Human Implant 1980
Dr Winkle, Dr Mirowski, the first ICD patient, Dr Heilman
ICD: First Human Implant 1980
A transvenous lead in SVC and a ventricular patch lead
Evolution of ICD Therapy
Benefits of ICD therapy:
1.
Identify the target population
2.
Implant the ICD successfully
3.
Optimize the ICD programming
ICD Implant Procedure (briefly)
1.
2.
3.
Preparation for implant
Consent. Model selection. Financial arrangement.
Blood tests. Antibiotics prophylaxis.
Defibrillation pads.
The team and the necessary equipment.
Venous access, pocket and lead placement
Cephalic cut-down or subclavian/axillary puncture.
Single or dual chamber ICD.
Active or passive fixation.
Lead testing
DF-4 connector vs IS-1/DF-1 connector
Assess P-wave/R-wave, pacing/defibrillation
impedance, pacing threshold
ICD Implant Procedure (briefly)
4.
 Defibrillation threshold (DFT) testing
Sedation.
VF induction by shock-on-T, burst stimulation,
direct current shock.
Rescue shock by external defibrillator standby.
Intracardiac electrogram analysis.
5.
Pocket closure. Postoperative care.
Device programming. CXR. Drug adjustment.
Subclavian Approach
Cephalic Approach
ICD Pocket
DF-4
DF-1
DF-4 lead
 one connection between the lead and the device,
with a single distal set screw to the tip
electrode.
 more convenient and reduce header size.
 the use of spring contacts (IS-1/DF-1 connector
use set screws to ensure high and constant
contact pressure).
 High-and low-voltage applications in the same
cavity (in IS-1/DF-1 devices, low- and highenergy contacts in separate cavities, embedded
in non-conducting material).
ICD implant
ICD Implant Procedure:
Complications
1.
2.
General: cardiac, pulmonary, neurological,etc.
Related to the ICD lead and pulse generator
 pocket hematoma
 (subclavian puncture) pneumothorax,
hemothorax, subclavian artery puncture, air
embolism, subclavian A-V fistula
 ICD system infection
 lead dislodgement, lead perforation, lead
wire fracture/insulation break
 Venous thrombosis
 etc
SPECIAL SITUATIONS,
TROUBLE-SHOOTING AND
MANAGEMENT
Venous access and lead placement
Special situations, trouble-shooting
and management
Venous access and lead placement (1):
Persistent left superior vena cava

ICD lead with long usable length

active fixation mechanism

Off SVC coil in DFT testing (SVC coil in
posterior position)

Alternative approach: Right-side implant
after venogram
Special situations, trouble-shooting
and management
Venous access and lead placement (2):
Multiple ICD leads

venogram to confirm vein patency

active fixation mechanism desirable

some separation in venous puncture site if
feasible

some separation between different ICD coils
in multiple fluoroscopic views
Special situations, trouble-shooting
and management
Venous access and lead placement (3):
Right-side ICD implant
Options available:

Right-side implant after venogram

Venoplasty

Epicardial leads

Subcutaneous ICD (S-ICD)
Subcutaneous ICD (S-ICD)

45cm lead with good
strength and durability

8-cm shocking coil, 2
sensing electrodes

Electrode was positioned
parallel to & 1-2cm to the
left of sternal midline

Pulse generator over the 6th
rib between the mid- &
anterior- axillary line

80-J shocks, up to 5 shocks,
reverse shock polarity
Bardy GH, et al.An entirelysubcutaneous
ICD.NEJM 2010:363(1);36-44
Subcutaneous ICD (S-ICD)
Limitations of S-ICD:
1.
No conventional pacing capability
(Post-shock pacing 200mA, 50ppm,
maximum 30 seconds, demand-based)
2.
No anti-tachycardia pacing (ATP) function
3.
Unable to upgrade to CRT-D
4.
S-ICD contraindicated for use with unipolar
pacemakers
Special situations, trouble-shooting
and management
Venous access and lead placement (4):
Pacemaker RV lead perforation

Active fixation RV lead for a MRI compatible
model

Emergency operation with intra-operative
findings: RV pacing wire perforated via RV
apex, then via pericardium and pleura;
defect over pericardium 0.5cm; 1L blood and
clots inside left pleural cavity.
SPECIAL SITUATIONS,
TROUBLE-SHOOTING AND
MANAGEMENT
Current of Injury
What is Current of Injury (COI)?
During implant procedure, injury to myocardium during
lead placement as shown on intracardiac electrogram.
More prominent in active lead than passive lead
 active fixation – helical screw into myocardium
traumatically
 passive fixation – axial pressure on lead-myocardium
interface
Current of Injury (COI)
COI at implant (RV passive lead)
10 minutes later…
Current of Injury (COI)
Active
V lead. COI ST elevation
A lead. COI ST elevation
>5mV or >25% ST elevation
>1mV or >25% ST elevation
Passive >2mV
>0.2mV

Consider threshold values and COI

COI subsides in 5-10 minutes usually
Saxonhouse et al. Current of injury predicts adequate active lead fixation in permanent
pacemaker/defibrilaltion leads. JACC 2005; 45(3): 412-7.
Current of Injury (COI)

COI confirms lead stability

Active leads have more prominent COI than
passive leads
Lack of COI indicates increased risk of lead
dislodgement
COI with high pacing threshold: consider to
recheck threshold 5-10 mins later before
reposition.


SPECIAL SITUATIONS,
TROUBLE-SHOOTING AND
MANAGEMENT
Defibrillation threshold (DFT) testing
Defibrillation Threshold (DFT) Testing.
Is it necessary?

64,227 initial ICD implant between April to Dec 2010 in
the NCDR Registry (National Cardiovascular Data ICD
Registry; ~90% of all ICDs implanted in US) analyzed
retrospectively.

DFT testing not performed in 29% patients and more
likely to have:
- heart failure
-
lower LVEF
atrial arrhythmias (e.g. AF)
primary prevention indication
CRT-D implant
Russo AM, et al. Patient, physician and procedural factors influencing the use
of DFT testing during initial ICD insertion. Pacing Clin Electrophysiol.
2013;36(12):1522-1531.
DFT Testing. Is it necessary?
ICD implant manuals approved by FDA include DFT testing.
But   
1. Better ICD devices nowadays and lead diagnostics
without performing a shock.
2. Risks of DFT testing (0.016% mortality; 0.026%
stroke/TIA)
3. Not guarantee clinically successful defibrillation (with
heart failure, ischemia, electrolyte abnormalities).
4. Previous trial: No relationship between DFT testing and
outcome in SCD-HeFT trial
1.Birnie D, et al. Complications associated with DFT testing: The Canadian experience. Heart Rhythm
2008;5:387-390.
2.Blatt JA, et al. No benefit from DFT testing in SCD-HeFT trial. J Cardiovasc Electrophysiol 2007; 4: S81.
DFT Testing. Is it necessary?

No consensus

In real-world clinical practice, paradoxically, those sicker
patients not having DFT testing may be most likely to
benefit from testing.

Ongoing Shockless Implant Evaluation (SIMPLE) trial
(but not powered to evaluate mortality).

“To test or not to test” vs “ For which patients is
testing important”
Defibrillation threshold (DFT)
The minimum amount of energy required
to reliably defibrillate the heart.
Note: DFT is not a static value and may
change over time, with drugs, and with
disease progress.
Successful defibrillation is probabilistic.
So although the term threshold is used,
there is no single energy level that is
always successful clinically.
Defibrillation Threshold (DFT) Testing
Traditional practice: Perform 2 VF inductions with
defibrillation energy 10J below the maximum device
output (i.e. a 10-J safety margin; not actually the
threshold).
Alternative approach: Upper limit of vulnerability
(ULV) is the lowest energy shock that does not
induce VF when delivered during the vulnerable
phase of ventricular repolarization. A 5-J ULV safety
margin is suggested.
High Defibrillation Threshold (DFT)
Management
1.
Rule out pneumothorax, loose set-screw
2.
Reposition RV lead (to a more apical-septal position).
Reverse polarity. Programmable waveform tilt/pulse
width (if available)
3.
High output device
4.
Add SQ away/additional coils
Add empiric sotalol/stop amiodarone
Question Time   
ICD Trouble-shooting
A 50-year-old man with dilated cardiomyopathy had a
single-chamber ICD implanted for primary prevention
indication.
An active lead was placed at the RV septum due to
poor sensing in RV apex.
One week later, he presented to A&E Department for
multiple ICD shocks while at home, asymptomatic.
There is no change in medications and all blood tests
were normal.
CXR showed the lead was dislodged to the level of
tricuspid annulus.
ICD interrogation for one of the device shocks
A shock (Rx1 Defib) was given for the device
diagnosis of “VF”.
Oversensing of the atrial signal by the ICD lead
causing double counting and inappropriate shocks.
DDx:
1. T wave oversense due to T wave amplitude/ morphology
changes e.g. hyperkalaema
2. T wave oversense due to QT interval change e.g.
antiarrhythmia drugs
3. Artefacts due to lead fracture
4. Electromagnetic interference
The patient was admitted to Medical General ward.
Due to tight CCL schedule, the lead revision was
scheduled 3 days later. The patient had a cardiac
arrest the day before operation and resuscitated.
ICD interrogation for the last device shock
VP
VP



Oversensing A signal (double counting) leads to
inappropriate shock.
The last device shock is proarrhythmic and causes VF.
VF is not sensed by the ICD due to the low
arrplitude of the ventricular electrogram. The ICD
initiates ventricular pacing (VP) during VF.
What will be your management for this patient with a
dislodged ICD lead if you see her in medical ward as a
cardiac consult?
Deactivation of the ICD with intensive cardiac
monitoring (e.g. CCU) until lead revision
Arrange early lead revision asap.
Summary
Implant procedure
 Special situations: persistent Lt SVC,
multiple leads, occluded subclavian
vein, RV lead perforation
 Current of Injury during implant
 DFT testing and high DFT
management

END
How Should I Program an ICD?
Evidence and Experience
1.
Basic ICD programmable parameters
2.
Evidence from recent clinical trials
3.
Summary
Dr Chan Kwok Keung
Department of Medicine
PYNEH, Hong Kong
6 April 2014
Two goals for a therapy:
1.
To help patients feel better
2.
To help patients live longer
or both.
ICD improves survival, but at what cost?
1.
Financial cost
2.
Morbidity of ICD therapy
complication of implant procedure
device alert/recall, lead failure(not discussed)
inappropriate therapy
(appropriate but) unnecessary therapy
affected
by
ICD
programming
and
antiarrhythmic drugs.



(this lecture will focus on ICD programming)
Causes for inappropriate therapy (Shock or ATP)

atrial arrhythmias (AF, atrial flutter, SVT)

oversensing due to lead fracture noise or overcounting
(T-wave oversensing, EMI, myopotentials)
Causes for unnecessary therapy (Shock or ATP)
Too aggressive treatment of VT than absolutely required

shock or ATP for premature detection of non-sustained
VT; premature ATP may accelerate NSVT

Shock for sustained pace-terminable VT
Implantable Cardioverter Defibrillator (ICD)
ICD treats ventricular tachyarrhythmias
Sensing
Detection
Therapy
Sensing in ICD: A major challenge…
A wide variation in the size of signals

stable and large normal ventricular signals

low amplitude VF signals
Sensing in ICD
Beat-to-beat auto-adjusting sensitivity
Sensing in ICD
Detection
Ventricular Fibrillation (VF)
 Rate cut-off (VF zone)
 Number of intervals for detection
(usually consecutive intervals not required;
high sensitivity)
Ventricular Tachycardia (VT)
 Rate cut-off [VT zone(s)]
 Number of intervals for detection
 Detection Enhancement/ SVT Discriminator
Detection Enhancement
Electrogram Morphology


Current electrogram signal compared with
stored normal template
Match percentage = 1 - (area of difference)
Detection Enhancement
Stability



To reduce inappropriate detection of atrial
arrhythmias eg atrial fibrillation (rhythm not “stable”
i.e. variable cycle length)
Each interval compared to previous intervals
Count as VT if the difference  the programmed
stability interval i.e. VT is “stable”
VT detection interval: 500ms
Stability 30ms
Detection Enhancement
Onset


To reduce inappropriate detection of sinus tachycardia
Average of current 4 intervals is compared to average
of previous 4 intervals
Current average  programmed
Previous average
onset percentage
i.e. onset is “sudden” in VT
Detection Enhancement: Onset
Onset percentage: 81%
Dual-chamber ICD: SVT discriminator
Dual-chamber ICD: SVT discriminator
PR Logic – Pattern and Rate Analysis
Discrimination of Lead Noise

Caused by pace-sense conductor fracture, loose set
screw, lead insulation breach.

Therapy avoided by comparing near-field channel (RV
tip to RV ring) to far-field channel (RV tip to Can/RV
coil to Can).
ICD Therapy
1. Defibrillation (in VF zone)
 Biphasic waveform high energy shock
2. Cardioversion (in VT zone)
 Synchronized biphasic waveform shock
ranges from < 1J to high energy
3. Antitachycardia pacing (in VT zone)
 Attempt to terminate VT with rapid pacing
 Patient more comfortable and therapy
energy-saving
4. Bradycardia pacing
High-energy Defibrillation
Monophasic


Biphasic
Biphasic waveforms are more effective than monophasic
waveforms
Capacitors act as high-voltage storage tanks. The
battery can ‘pump’ energy into the capacitor which holds
up the energy. So a 3.2V battery can fill a capacitor to
~30-36J (700-800V) to defibrillate the heart.
Defibrillation threshold (DFT)
The minimum amount of energy required
to reliably defibrillate the heart.
Note: DFT is not a static value and may
change over time, with drugs, and with
disease progress.
Successful defibrillation is probabilistic.
So although the term threshold is used,
there is no single energy level that is
always successful clinically.
Probability of Successful Defibrillation
and Shock Strength
125
% Success
100
75
50
25
0
0
5
10
Energy (Joules)
15
20
Low Energy Cardioversion

For termination of ventricular
tachycardia

Shocks delivered at 0.1J up to several
Joules, synchronized to R wave

Shocks under 2J are much
comfortable for patients
Antitachycardia Pacing (ATP)
Antitachycardia Pacing (ATP)

ATP is not painful

ATP consumes minimal amount of battery

May be effective in some VTs, but may
also be proarrhythmic

PainFREE Rx 2 study: ATP terminated
73% of fast VT (18 of 24 intervals, 188250bpm).
Wathen MS, et al. PainFREE Rx 2. Circulation 2004;110:2591-96.
Evidence from recent trials
Traditional Concept in the past

Quick detection: the longer the arrhythmia, the
more likely a patient to have
symptoms e.g. syncope

Lower cut-off rate: if a higher cut-off rate is
used, a haemodynamically
significant VT will be missed,
leading to syncope or VF.

But primary prevention indications were
uncommon in the past.
Is the ICD programming appropriate
to the patient needs?
Causes for inappropriate therapy (Shock or ATP)

atrial arrhythmias (AF, atrial flutter, SVT)

oversensing due to lead fracture noise or overcounting
(T-wave oversensing, EMI, myopotentials)
Causes for unnecessary therapy (Shock or ATP)
Too aggressive treatment of VT than absolutely required

shock or ATP for premature detection of non-sustained
VT; premature ATP may accelerate NSVT

Shock for sustained pace-terminable VT
Reduction in Inappropriate Therapy and
mortality through ICD Programming
(MADIT-RIT trial)

A randomized, single-blind, multicenter clinical study

1500 patients with either ischaemic or nonischaemic
disease with an indication for a primary-prevention dualchamber ICD or CRTD. Patients with atrial fibrillation or
device replacement excluded.

Patients were assigned to one of three ICD programming
groups with the primary objective of finding their rate of
a first occurrence of inappropriate ATP or shocks.
Moss A., etal. NEJM 2012; 367: 2275-83
MADIT-RIT: Three Treatment Arms
Arm A
(Conventional)
Arm B
(High-rate)
Arm C
(Duration-delay)
Zone 1:
170 bpm, 2.5s delay
Onset/Stability Detection
Enhancements ON
ATP + Shock
Zone 1:
170 bpm
Monitor only
Zone 1:
170 bpm, 60s delay
Rhythm ID Detection
Enhancements ON
ATP + Shock
Zone 2:
200 bpm, 1s delay
Quick Convert ATP
Shock
Zone 2:
200 bpm, 2.5s delay
Quick Convert ATP
Shock
Zone 2:
200 bpm, 12s delay
Rhythm ID Detection
Enhancements ON
ATP + Shock
Zone 3:
250 bpm, 2.5s delay
Quick Convert ATP +
Shock
NOTE:

The ICD was not a new type of ICD.

The programming choices were not new.

Aim
to
ignore
the
slower
tachyarrhythmias in High-rate and those
of shorter duration in Duration-delay.
MADIT-RIT Results

During an average follow-up of 1.4 years, high-rate
therapy and delayed ICD therapy, as compared with
conventional device programming, associated with
- reduction in a first occurrence of inappropriate therapy
- reduction in all-cause mortality
- no significant difference in adverse events
e.g. syncope

There was significant reduction by more than 70% of
inappropriate therapy in both high-rate and delayed
therapy groups

Mortality was reduced by 55% in high-rate group
(p=0.01) and by 44% in the delayed-therapy group
(p=0.06).
MADIT-RIT
Lession: Treat sustained tachyarrhythmias only
It does not favor quick detection and therapy.
Note that in MADIT-RIT:
• primary prevention indication only
• dual-chamber ICD and CRT-D only
• exclude AF patients.
Effects of Long-detection Interval vs
Standard-detection Interval for ICDs on
Antitachycardia Pacing and Shock Delivery
(ADVANCE III trial)

A randomized, single-blind study to determine
whether using 30 of 40 intervals to detect VT
(long detection) reduces ATP and Shock compared
with 18 of 24 intervals (standard detection).

Patients with primary or secondary prevention,
single- or dual-chamber ICD or CRT-D, sinus or
AF.
Gasparini M, et al. JAMA 2013; 309:1903-11
ADVANCE III trial Results:

After a median follow-up of 1 year, the longdetection group had significantly less ICD therapies
(ATP and shocks) and inappropriate shocks.
There was significant
hospitalizations.
reduction
in
all-cause
No difference in arrhythmia syncope and mortality.
Lession: Broaden the long detection applicability to
include secondary prevention, singlechamber ICD and AF patients.
Inappropriate shock rates in patients with
single chamber ICDs using a novel suite of
detection algorithms
(PainFree SST study)

A non-randomized trial with primary endpoint of the
rate of inappropriate shocks at one year post implant.

Single chamber ICD, primary or secondary prevention,
initial implant or replacement, sinus or AF.

A special detection algorithm includes wavelet
morphology
analysis,
discriminating
T
wave,
assessment of lead integrity or noise and improved
recognition of nonsustained episodes.
Meijer A, et al. Europace June 2013
PainFree SST study Results

757 patients with single-chamber ICD

97.6% of patients free of inappropriate shocks
during the first year post implant.
Lession: reducing inappropriate shock rate below
3% at 1 year is possible
Programming ICDs in patients with
primary prevention indication to prolong
time to first shock
(PROVIDE study)

A randomized study of primary prevention ICD
(single or dual chamber or CRTD) in 1670 patients.

A combination of programmed parameters (higher
detection rates, longer detection intervals, empiric
ATP,
SVT
discriminators)
vs
conventional
parameters.

Result: reduced ICD therapies without increasing
arrhythmic
syncope
and
reduced
all-cause
mortality.
Saeed M, et al. J Cardiovasc Electrophysiol 2014; 25(1): 52-59
Safety and efficacy of strategic ICD
programming to reduce shock delivery burden
in a primary prevention patient population

A non-randomized retrospective analysis of 300 ICD
patients of various manufacturers.

Strategic ICD programming to reduce shocks.

64% risk reduction in primary endpoint (composite
of death and appropriate shocks) and 70%
reduction in inappropriate shocks.
Buber J, et al. Europace 2014; 16(2): 227-234
The impact of prolonged arrhythmia detection
times on outcomes: a meta-analysis

4896 patients from
PROVIDE, RELEVANT.
MADIT-RIT,
ADVANCE
3,

Reduced mortality by 23%

Reduced inappropriate shocks and both appropriate
and inappropriate ATP significantly.
Scott PA, et al. Heart Rhythm 2014; D01: 10.1016. Abstract.
Summary
1.
ICD therapy has morbidity. The benefits of an ICD are
greatly affected by its programming
2.
Avoid inappropriate therapy and unnecessary therapy
(less pain, less hospitalization, better QOL, improved
survival).
3.
To be certain that there is a sustained tachyarrhythmia
before treating the rhythm

prolonged duration of arrhythmia detection
faster rate of arrhythmia detection
use of ATP
algorithms for discrimination of SVT



END