Transcript here - Arrhythmia Watch

Is It Time to Redefine ICD
Therapy ?
The Importance of Reducing Shocks
1
30 Years Ago…
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Mortality Reduction with ICDs
Secondary Prevention
AVID1
CASH2
CIDS3
MADIT4
MUSTT5
MADIT II6
SCD-HeFT7
1. The AVID Investigators. N Engl J Med. 1997;337:1576-1583. 2. Kuck KH. Circulation. 2000;102:748-754. 3. Connolly.
Circulation. 2000;101:1297-1302. 4. Moss AJ, et al. N Engl J Med. 1996;335:1933-1940. 5. Buxton AE, et al. N Engl J Med.
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1999;341:1882-1890. 6. Moss AJ, et al. N Engl J Med. 2002;346:877-883. 7. Bardy GH, et al. N Engl J Med. 2005;352:225-237.
Does ICD Therapy = A Life-Saving Event?
Overtreatment in Secondary
1
Prevention
68%
6.6X
10.20%
AVID 2 year follow-up 4
Control: SCD/Cardiac Arrest/Sustained VT
ICD Therapy
Annual Rate of Sudden Death
Marked Over-Treatment in Primary and
Secondary Prevention Patients
Overtreatment in Primary
Prevention1
5 yr 60%
VT/VF
shocks
16
12
5 yr 37%
SCD
4.6
5.7X
2.7X
2.8
MUSTT
2
Non-ICD Sudden Death
SCD-HeFT
3
ICD Patient with VT/VF Rx
1. Wathen M. Am Heart J. 2007;153(4 suppl):44-52. 2. Buxton AE. N Engl J Med. 1999;341:1882-1890.
3. Bardy GH. N Engl J Med. 2005;352:225-237. 4. The AVID Investigators. N Engl J Med. 1997;337:1576-1583.
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ICD Therapy: different types of shocks
• Appropriate shocks: Shocks triggered by potentially
life-threatening arrhythmias
– Unnecessary shocks: Other painless therapy can be used to
terminate arrhythmia
– Necessary shocks : Shock for arrhythmias not terminated by
other means
• Inappropriate Shocks: Shocks triggered by an
inappropriate detection
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Up to 21% of ICD Patients Receive
Inappropriate Shocks1-4
Incidence of Innappropriate Shocks in the ICD Population
% of patients shocked
% of patients receiving
inappropriate shocks
% of patients receiving
appropriate shocks
% of patients receiving
all cause shocks
38%
39%
33%
26%
21%
12% 14%
20 months MADIT-II
ICDs2
1
2
3
4
18%
17%
22%
16%
n.a
29 months DEFINITE
ICDs1
45 months SCD-HeFT
ICDs 3
5 years ALTITUDE
ICDs4
Kadish A, et al. N Engl J Med. 2004;350:2151-2158.
Daubert JP, et. J Am Coll Cardiol. 2008;51:1357-1365.
Poole JE, et al. N Engl J Med. 2008;359:1009-1017.
Saxon A. L. Circulation. 2010;122:2359-2367.
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ICD Shocks in Atrial Fibrillation
• 913 consecutive ICD pts: 73% had no AF, 9% paroxysmal AF,
7% persistent AF, 11% permanent AF
• Permanent AF: mortality risk doubled, higher risk any therapy
• Paroxysmal/persistent AF: 3 times higher risk of inappropriate
shocks
Appropriate device shock
Inappropriate device shock
Black line: no AF
Green line: Paroxysmal AF
Orange line: Persistent AF
Red line: Permanent AF
Borleffs J. J Am Coll Cardiol 2010; 55: 879–885
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Prognostic Importance of ICD Shocks
• SCD-HeFT patients who received and ICD (n=811)
• 33.2% received shocks: 15.8% only appropriate, 10.7% only
inappropriate and 6.7% both
• Patients who receive shocks for any arrhythmia have a higher
risk of death than those who do not receive such shocks
Poole JE. N Engl J Med 2008; 359: 1009-1017
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Shocks but not ATP are associated with
Higher Mortality
• Retrospective analysis of pooled data
– PainFREE I and II, EMPIRIC and PREPARE
– 2,135 pts, EF 31%, 87% CAD, 55% NYHA II/III, 42% NYHA I/ no CHF
Sweeney M. Heart Rhythm 2010; 7: 353 - 360
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Shocks Affect Patients’ Quality of Life
• Psychological impact of shocks on patients has been
clinically studied
• For patients, simply the fear of shocks can be
disruptive to a normal, active life
• Shock reduction has been shown to improve ICD
patient’s quality of life and, in the process, may
reduce a patient’s greatest fear: fear of getting
shocked
Sears SE, et al. Clin Cardiol. 2003;26:107-111. Irvine J, et al. Am Heart J. 2002;144:282-289.
Wathen MS, et al. Circulation. 2004;110:2591-2596.
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Potential Benefits of Shock Reduction
• Improved patient quality of life
• Increased ICD therapy acceptance
• Extended ICD longevity
• Less demand for post-shock care
• May improve survival benefits of ICDs
• Reduced healthcare spending
Wathen MS. Circulation 2001; 104: 796-801. Wathen MS. Circulation 2004; 110: 2591-2596
Sears SE Jr. Clin Cardiol. 2003; 26(3): 107-111. Ahmad M. PACE. 2000; 23(6): 934-938.
Sweeney M. Heart Rhythm 2010; 7: 353 - 360
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Rethinking the Job of the ICD
“For every episode of sudden death, cardiac arrest, or
sustained VT, the ICD should produce a therapy. In
other words, in a population of patients who receive
an ICD, if there is a 5% annual risk of sudden death,
then 5% of patients should be treated.”
Wathen MS. Am Heart J. 2007;153(4 Suppl):44-52.
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Reducing inappropriate and
unnecessary shocks
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What Is the Job of the ICD?
• Detection
– Reliable detection of VT/VF
• Therapy
– Reliable termination of potentially lethal ventricular
tachyarrhythmias – either through the use of ATP
(antitachycardia pacing) or if needed, delivery of a shock
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What Are the Challenges to
Shock Reduction Programming?
“Changing habits”
• ATP (antitachycardia pacing) is often neglected:
Why?
– Efficacy questioned – especially for Fast VTs (> 188 bpm)
– Concern about VT acceleration
– Concern about syncope due to delayed therapy
• Detect times are too short:
– Over-treatment of VT (ICD Rx is delivered for NSVTs)
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Causes of Shocks
Poole JE. Presented at the Heart Rhythm Society 2004.
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Programming Strategies to Safely
Reduce Shocks
ATP Before and During
Charging
PREPARE Programming
Charge time < 10 s even at
end of life
Poole JE. Presented at the Heart Rhythm Society 2004.
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ATP for Fast VTs Reduces Shocks
• PainFREE Rx I: 220 ICD pts. with CAD received empirical ATP
(up to 2) for fast VTs (188-250 bpm), NID 12/16
• ATP terminated 396 out of 446 FVT episodes (89%)
• VT acceleration and FVT syncope were rare (4 and 2% resp.)
VF
3%
ATP failed
15%
FVT
40%
VT
57%
ATP success
85%
Note: ATP success was 89% with 3 ATP; 85% with up to 2
ATP (protocol), 77% adjusted efficacy rate
Wathen MS. Circulation 2001; 104: 796-801
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ATP for Fast VTs Reduces Shocks II
• PainFREE Rx II: 634 prim./sec. prevention ICD pts. randomized
to empirical ATP or shock for fast VTs (188-250 bpm), NID 18/24
• ATP successfully terminated 3 out of 4 Fast VTs
• ATP is highly effective, equally safe and improves QoL
ATP
2%
ATP failed
Spontaneous
Termination
28%
34%
ATP success
72%
ATP Arm
n=284 episodes
Wathen MS. Circulation 2004; 110: 2591-2596
Shocked
64%
Shock Arm
n=147 episodes
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PainFREE Rx II Lessons
“These observations, combined with the established
efficacy of ATP for slower VT, reposition the ICD as
primarily an ATP device with only occasional backup
defibrillation.”
Wathen MS. Circulation 2004; 110: 2591-2596
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ATP During Charging™ in PainFREE Study
• Made ATP nominal in ICDs
• Deliver single sequence of ATP while the capacitor
charges for a shock
• No delay in delivery of shock therapy
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Empiric Programming is Effective
• 900 ICD pts. randomized to Tailored or Empiric (ATP for fast VTs
(200-250bpm), NID 18/24) programming
• Empiric was non-inferior to Tailored programming, had less
unscheduled hospitalization and reduction of pts. with 5 or
more shocks for all-cause and true VT/VF
Wilkoff BL. J Am Coll Cardiol 2006; 48: 330-339
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Strategic Programming Reduces Shocks
• PREPARE: Prospective, cohort controlled study
• 700 primary prevention ICD or CRT-D patients programmed to
ATP for fast VT (182-250 bpm), NID 30/40, VT monitor (<182 bpm)
• Reduction of unnecessary and inappropriate shocks, improved
survival
Wilkoff BL. J Am Coll Cardiol 2008; 52: 541-550
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CRT-D with NID programmed to 30/40
• RELEVANT: 324 primary prevention pts. with non-ischemic
etiology with CRT-D programmed to: NID 30/40 or 12/16 (control)
• Study arm showed:
– Better event-free survival to first delivered therapy for total, appropriate
and inappropriate episodes
– Lower total number of delivered shocks
– Reduced HF hospitalization
Gasparini M. Eur Heart J 2009; 30(22): 2758-2767
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Longer NID – In Real Life It Works!!
Completely asymptomatic
patient. Seen for routine
follow-up.
#1
#18
#24
#12
#28
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Lots of Data and Experience Now Suggest
For Primary Prevention Patients:
Use of ATP
Prolonged Detection
Reduced Shocks in ICD patients
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New Algorithms to Reduce Shocks
ATP Before and During
Charging
• Lead noise discrimination
and alert
• T Wave OS Discrimination
• Programmable RV Sensing
• Programmable Sensitivity
• Combine Wavelet + PR
Logic in dual/triple chamber
• Apply SVT discrimination in
the VF zone
• More reliable confirmation at
the end of the charge
• PREPARE Programming
• Charge time < 10 s
Poole JE. Presented at the Heart Rhythm Society 2004.
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Protecta™ SmartShock™ Technology
Six exclusive shock reduction algorithms that do not
reduce sensitivity (nominally programmed ON):
•Reduced shocks for SVT
– PR Logic® + Wavelet (dual and triple chamber devices)
– SVT limit nominally in the VF zone
•Reduced shocks for T-wave oversensing
– T Wave Discrimination
•Reduced shocks for Lead fracture and lead noise
– Lead noise discrimination and alert
– Lead integrity alert
•Reduced shocks for non sustained VT
– Confirmation +
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Reducing Shocks Due to SVT
• 20% of inappropriate shocks due to SVTs in VT/VF
zone
• Avoid shocks for rapidly-conducted AF in VF zone
and better discriminate sudden onset SVT in VT zone
Poole JE. Presented at the Heart Rhythm Society 2004.
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Improved SVT Discrimination
• PR Logic® + Wavelet
– Combines morphology and A-V pattern recognition to better
discriminate against all types (in dual and triple chamber devices)
– PR Logic: Effectively discriminates Sinus Tach and AF/Aflutter
– Wavelet: Uses EGM morphology to improve SVT discrimination
(i.e., conducted AF and sudden onset SVT)
Wavelet
Medtronic Protecta™ and Protecta™ XT system reference guides.
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SVT Limit in the VF Zone
• PR Logic® and Wavelet are nominally ON with an
SVT limit zone set to 260 ms (231 bpm)
• Only Medtronic can program discriminators in the
VF zone – down to 240 ms (250 bpm)
Discrimination in the
VF Zone (nominal)
• SVT Limit = 260 ms
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Reduce Shocks Due to T-wave
Oversensing
• Algorithms to address TWOS may require manual
sensitivity adjustment after shocks for TWOS
• This has the potential for undersensing R-waves and
affecting ventricular detection sensitivity
2. Gunderson BD, et al. Heart Rhythm 2004; 1: S244.
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First and Only T-Wave Discriminator
• New approach to T-wave OS: Frequency analysis
versus manual sensitivity adjustment
• Fully automatic
• Does not require an initial shock followed by
reprogramming
• No compromise on VF detection sensitivity:
– Assures that all R-waves are appropriately sensed, minimizing
the chance of impacting ventricular sensitivity
Medtronic Protecta™ and Protecta™ XT system reference guides.
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T Wave Oversensing Algorithm
Uses both signal-frequency content and pattern
analysis to distinguish R-T pattern
Sense EGM: in current devices, signal is
filtered to isolate R waves. May oversense
T waves.
In Protecta™, differentiation of sense EGM
enlarges the ratio of R-to-T– wave
amplitudes, enabling R-T pattern recognition.
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Protecta™ TWOS Algorithm
The algorithm is
withholding the therapy
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Reducing Shocks Due to RV Lead Noise
• Cumulative lead malfunction incidence is 4.6% at 10
years across manufacturers
• Lead malfunction resulted in inappropriate shocks in
76% of the cases1
1. Eckstein J, et al. Circulation. 2008;117:2727-2733.
2. Gunderson BD, et al. Heart Rhythm. 2004;1:S244.
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Lead Integrity Suite
Combines two algorithms that detect, alert,
and withhold inappropriate therapy for lead failure:
Lead Integrity Alert
• Provides advance warning for lead fracture and extends the VF
detection time
Lead Noise Discriminator + Alert
• Identifies oversensing due to noise artifacts and provides ability
to withhold therapy delivery
• No compromise of VT/VF detection sensitivity
• Notifies clinician of potential lead noise
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Lead Integrity Suite on the MDT
CareLink® Network
• CareLink website sends a CareAlert Notification (text
message, or email)
• Clinic chooses whether this alert should be red,
yellow, or website only up to a patient level
CareLink
functionality
with wireless
devices
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Lead Integrity Alert Avoids
Inappropriate Shocks in Lead Failure
• Fractures in pace-sense electrodes of ICDs often lead to
inappropriate shocks due to oversensing
• LIA is based on lead impedance and an oversensing trigger
• When triggered it extends the NID to 30 out of 40
• LIA provided at least 3-day warning of inappropriate shocks in
76% of pts.
Swerdlow CD. Circulation. 2008; 118: 2122-2129
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Lead Integrity Alert Reduces
Inappropriate Shocks in Lead Failure
• Evaluation of LIA algorithm by comparing pts. with
Sprint Fidelis lead failure without versus with LIA
• Pts. with LIA had:
– Less often inappropriate shocks as first sign of failure (p=0.0006)
– Less inappropriate shocks (p=0.017)
Kallinen LM. Heart Rhythm 2010; 7: 1048 –1055
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LIA Reduces Inappropriate Shocks
• 213 pts. with lead fracture and LIA were compared to
213 pts. with lead fracture but without LIA
• LIA group had 46% reduction in percentage of pts.
receiving inappropriate shocks
Swerdlow CD. Circulation. 2010; 122: 1449-1455
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LIA: Solution for Proactive Protection
• Reduces the chance of inappropriate shocks
– Increases sensitivity of detecting lead fractures compared with
fixed impedance
– Automatically and safely extends the VF detection NID to 30/40
when the alert is triggered
• Helps you to manage your patient
– Monitors lead integrity continuously
– Provides improved diagnostics triggered by oversensing
– Allows easy access to the information via CareLink™
• Increases the chance to react early enough
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RV Lead Noise Discrimination
• Lead-noise oversensing is typically isolated to the
near field sensing signal
• Compare near-field sensing signal:
– Far field EGM used to confirm senses
Compares farfield cardiac
activity to
sensed event
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Additional Safety Features:
Programmable Timeouts
• Timeout addresses concerns about sustained high rates for long period
of time and allows options for individual programming
• Allow to override the discrimination features and deliver therapy when a
VT continues beyond a programmed length of time
• Timeouts available in Protecta:
– Lead noise discriminator Timeout: Nominally ON (45 seconds)
– SVT discriminators (PR Logic® and Wavelet) timeout:
High-Rate
Timeout
Applies to VT and VF Zone
Nominally OFF
VF HighRate
Timeout
Applies only to the VF Zone
Nominally ON in VR (45 seconds)
Nominally OFF in DR/CRT-D
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Reducing Shocks Due to
Non Sustained Ventricular Arrhythmias
• Patients can receive unnecessary shocks for rhythms
that are detected but terminate prior to end of the
charge, or for PVCs that occur once the arrhythmia
terminates
Poole JE. Presented at the Heart Rhythm Society 2004.
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Confirmation +
• Better identifies tachycardia termination with ATP or
spontaneously during charge and aborts the shock
• Avoids inappropriate shocks for single PVC or single
fast events at the end of the charge
Confirmation +
CONFIRMATION
Modify determination of
persisting arrhythmia
based on intrinsic
detected rate vs.
programmed lower
therapy rate (sync
interval)
Confirmation now available after
ATP During Charging sequence
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Confirmation +
Rx1 confirmed during redetection
Abort #1
Abort #2
Medtronic Protecta™ and Protecta™ XT system reference guides.
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Safe Shock Reduction Strategies
• ATP reduces shocks for VT
• Longer detection interval – coupled with shorter
charge times – allows more episodes to terminate
spontaneously
• Combined approach to reduce all types of
inappropriate shocks:
– Improved SVT discrimination
– Better TWOS and lead noise algorithms
– Improved confirmation algorithm reduces shocks for NSVT
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Clinical Experience: Computer Modeling
• Computer modeling addresses some of the
limitations of randomized controlled trials:
–
–
–
–
Fast and early results
Individual algorithms can be tested separately
Possibility to repeat the test many times
Cost-saving
• Virtual ICD study predicts shock reduction results for
a combination of strategies/features using a
computer model and real ICD episode data from a
long-term clinical study
Combining Shock Reduction Strategies to Enhance ICD Therapy: A Role for Computer Modeling
Volosin K. J Cardiovasc Electrophysiol 2010. Advance access published on Oct. 11, 2010
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Computer Modeling: Approach
• Build the model - Virtual ICD
– Based on data from prior studies (PainFree II, WAVE, ENTRUST)
• Validate the model
– Adjudicated episodes from
the EMPIRIC trial (ATP, PR-Logic)
• Apply the model
– Adjudicated SCD-HeFT episodes were used to establish clinically
understandable performance predictions
Combining Shock Reduction Strategies to Enhance ICD Therapy: A Role for Computer Modeling
Volosin K. J Cardiovasc Electrophysiol 2010. Advance access published on Oct. 11, 2010
50
Computer Modeling: Results of New Algorithms
With ProtectaTM family of devices, 98% of patients are free
of inappropriate shocks at 1 year, and 92% at 5 years.
With
SmartShock™
Technology
† All shocked episodes from SCD-HeFT that had protocol defined programming and were determined not to be continuations of
previous true VT/VF were included for these calculations (736/1,233, 59.7% of total SCD-HeFT treated episodes).
* Only the 786 subjects whose devices were initially programmed to SCD-HeFT protocol parameters were included in the analysis.
** Derived from the subset of cohort episodes (650/736) for which NID of 30/40 could be evaluated.
Combining Shock Reduction Strategies to Enhance ICD Therapy: A Role for Computer Modeling
Volosin K. J Cardiovasc Electrophysiol 2010. Advance access published on Oct. 11, 2010
51
Future Clinical Evidence
The PainFree SST – a prospective clinical study – is
conducted to further understand the utility of shock
reduction strategies and anticipated to provide
additional evidence
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“The reputation of the ICD as a “shock box” is a significant source
of anxiety to potential patients. Today, third generation ICDs are
much improved in their sensing and tiered therapy options to
reduce shocks and their resulting distress.”
Dr. Sam Sears
Professor and Director of Health Psychology
East Carolina University, Greenville, NC
Sears SF, et al. Heart. 2002; 87: 488-493.
“Near total reliance on shocks may have underestimated the ICD
survival benefit in clinical trials. Strategies to minimize shocks
may further improve survival in ICD patients.”1
Dr. Michael O. Sweeney
Director, Cardiac Pacing and Implantable Device Therapies
Bigham and Women’s Hospital, Boston, MA
Sweeney MO, et al. Heart Rhythm. 2010;7:353-360.
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