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St. Jude Medical
An educational handbook
on Atrial Fibrillation
Overview
Risk of Stroke
Suppressive Therapies
Curative Therapies
Clinical Trials
References
Atrial Fibrillation (AF)
Cause, Effect, and Treatments
AF is a very fast and disorganized heartbeat that occurs in the upper
chambers of the heart (the atria). During AF, the atria may beat between
350 and 600 times per minute, making the atria appear to quiver (fibrillate)
rather than beat. As a result, the heart loses its ability to pump efficiently,
making AF a major risk factor for stroke.1-3
What Causes AF?
AF is the most common type of abnormal heart rhythm. The estimated
prevalence is 0.4% to 1% in the general population, increasing with age.
Studies show a lower prevalence in those below the age of 60, increasing to
8% in those older than 80.1
The prevalence and impact of AF on clinical outcomes strongly suggests
the need for effective treatment options. In the following pages you will find
information on AF, treatment options, and research studies (sponsored by
St. Jude Medical) aimed to improve the treatment of AF.
Several conditions can contribute to the development of AF, including:
■■ High blood pressure
■■ Cardiomyopathy
■■ Coronary artery disease
■■ Congenital heart disease
■■ Chronic lung disease
■■ Pulmonary embolism
■■ Heart Failure
What are the effects of AF?
■■
■■
■■
Increase risk of stroke1-3
Dizziness
Palpitations
■■
■■
Racing heart
Lack of energy
What are treatment options for AF?
■■
Suppressive therapies
–– Drugs
–– Electrical cardioversion
–– Implantable devices
■■
Curative therapies
–– Surgical ablation
–– Catheter ablation
Overview
Risk of Stroke
Suppressive Therapies
Curative Therapies
Risk of Stroke: One in every six strokes occurs in an AF
patient4
■■
■■
■■
Clinical Trials
References
Appropriate Therapy in AF Can Reduce the Risk of
Stroke
AF causes the heart to lose its ability to pump efficiently which can cause
blood to pool and clot in the atria. Even small blood clots can cause
problems if they leave the heart and travel to other parts of the body. They
may clog arteries or disrupt blood supply to vital organs. If a blood clot
moves to an artery in the brain – which often occurs in cases of AF – a
stroke can occur.
Numerous clinical trials have provided an extensive evidence base for the
use of antithrombotic therapy in AF.7 A meta-analysis of 29 trials including
28,044 participants was conducted to characterize the efficacy and safety of
antithrombotic agents for stroke prevention in patients who have AF. Of these
trials, 6 evaluated the effect of adjusted-dose warfarin and cumulatively
showed that adjusted-dose warfarin reduced stroke by 64%.8
Studies have shown that the risk of stroke for people with AF is two to
seven times greater than for those without it.4 Data that date back to the
late 1970’s showed that the rate of stroke was 5.6 times greater in patients
with chronic AF than those who were free of AF.5
The Goals of an AF Treatment Plan
Recent data from the ASSERT trial reports that even subclinical atrial
tachyarrhythmias are associated with an increased risk of stroke
(p<0.001).6 These results suggest that early notification of subclinical atrial
tachyarrhythmias through device alerts and monitors may allow physicians
to treat patients earlier with the appropriate pharmacological therapy to
reduce the risk of stroke.
The treatment prescribed for an AF patient is dependent on the severity
of their AF, their symptoms, and their lifestyles. Treatment options can be
placed in two categories: suppressive and curative. Both treatment options
aim to:
■■
Restore a normal heart rhythm
■■
Control heart rate
■■
Reduce risk of stroke
Overview
Risk of Stroke
Suppressive Therapies
Curative Therapies
Clinical Trials
References
Suppressive Therapies Work to Control Symptoms
Implantable Devices
Pharmacological Therapy
A device such as an implantable defibrillator or pacemaker can
be used to suppress the symptoms of AF with low-dose electrical
energy.
Several different types of medication can be used to treat AF. Some
medicines can be used to help restore and maintain a normal heart rhythm
and others may be prescribed to control heart rate. Anticoagulant medicines
are often prescribed for people with AF to help reduce the risk of blood clots
forming and causing a stroke.
The AF Suppression™ algorithm is a feature on St. Jude Medical
devices that is clinically proven to reduce AT/AF burden and improve
quality of life by pacing in the atrium just above the
intrinsic rate.9 Furthermore, these devices
have programmable AT/AF alert triggers to
provide real-time insight into changes in atrial
arrhythmia status. Improved lead technology
(such as the OptiSense® Optim® lead) results
in more accurate atrial sensing and less
far-field interference.10
In addition, some devices have alerts
to notify physicians that their patient
is having an AF episode. This type
of timely notification may provide
physicians with the opportunity
for early intervention.
Electrical Cardioversion
Occasional episodes of AF can be treated electrically with a procedure
called cardioversion. During the procedure, an electrical shock is delivered
to the heart to stop AF and restore a normal heart rhythm. This procedure is
performed at the hospital under temporary anesthesia.
Overview
Risk of Stroke
Suppressive Therapies
Curative Therapies
Clinical Trials
References
Curative Therapies Are Designed to Eliminate the Cause of the Condition and Have the Potential to Cure
Surgical Ablation
Catheter Ablation
Surgical ablation may be an option for those who cannot tolerate medication
or for whom these and/or other therapies have been ineffective.
During the catheter ablation procedure, small wires or electrode catheters
are placed through a blood vessel into the heart to record electrical
activity and help locate the problem areas responsible for AF.
During this procedure a physician applies energy to the outside of the heart,
creating a lesion or scar that blocks abnormal electrical signals that cause AF.
Patients who undergo cardiac surgery, such as a valve replacement or
coronary artery bypass graft (CABG), may be advised to undergo AF ablation
at the same time.
After locating these areas a physician uses an ablation catheter to apply
high-frequency energy to the inside of the heart, creating a lesion or scar.
As a result, the tissue’s electrical pathway is isolated from the rest of the
heart–making this tissue incapable of producing or sustaining AF.
Potential risks of this procedure may
include bleeding, swelling or bruising
where the catheters were inserted,
infection, damage to blood vessels,
blood clots, damage of the heart’s
normal electrical system, and risk
related to anesthesia.
Potential benefits of this minimally
invasive procedure may include
permanent cessation of the
arrhythmia requiring no other
treatment, freedom from long-term
use of blood thinning medications,
and a relatively
fast recovery.
Currently St. Jude Medical does not
have surgical and catheter ablation
tools that have an FDA approved
indication for treatment of AF.
Catheter inserted
through a blood
vessle in the groin
Catheter inserted
through a blood
vessle in the arm
Overview
Risk of Stroke
Suppressive Therapies
Curative Therapies
Clinical Trials
References
St. Jude Medical is dedicated to the development of safe and effective
device-based treatment options for atrial fibrillation. Highlighted below
are St. Jude Medical sponsored clinical studies that focus on AF.
CABANA: Catheter Ablation versus Anti-arrhythmic Drug Therapy
for Atrial Fibrillation Trial11
■■ The CABANA trial has the overall goal of establishing the appropriate roles
for medical and ablative intervention for atrial fibrillation (AF). The CABANA
trial is designed to test the hypothesis that the treatment strategy of left
atrial catheter ablation for the purpose of eliminating AF will be superior to
current state-of-the-art therapy with either rate control or rhythm control
drugs for reducing total mortality in patients with untreated or incompletely
treated AF.
MAGIC-AF: Modified Stepwise Ablation Guided by Low Dose Ibutilide
in Chronic Atrial Fibrillation12
■■ The aim of the MAGIC-AF trial is to determine if administering a standard
dose of the drug ibutilide at a standard time in the procedure can allow for
a reduction in the ablation procedure time.
STAR-AF: Substrate Versus Trigger Ablation for Reduction of
Atrial Fibrillation Trial13
■■ The purpose of this study was to compare the following AF ablation
techniques: ablation of complex fractionated electrograms (CFE) alone,
pulmonary vein isolation (PVI) alone, and combined PVI and CFE (PVI
+CFE). This study showed that compared to PVI and CFE alone, the
combination of PVI+CFE had the highest freedom from AF in patients
presenting with high-burden paroxysmal/persistent AF.
IRASE AF: Irrigated Ablation System Evaluation for AF14
■■ The purpose of this study is to test the safety and effectiveness of an
Irrigated Ablation System for the treatment of symptomatic paroxysmal
atrial fibrillation.
ASSERT: Asymptomatic Atrial Fibrillation and Stroke Evaluation in
Pacemaker Patients and the Atrial Fibrillation Reduction Atrial
Pacing Trial15
■■ The ASSERT study demonstrated that in device patients with no prior
history of AF, subclinical atrial tachyarrhythmias are associated with an
2.49-fold increase risk of stroke or system embolism (p=0.007) and a
5.56-fold increase risk of clinical atrial fibrillation (p<0.001)
Overview
Risk of Stroke
Suppressive Therapies
Curative Therapies
Clinical Trials
References
References
1.Fuster V, et al. 2011 ACC/AHA/HRS Focused Updates Incorporated ino the ACC/AHA/ESC 2006 Guidelines for Management of Patients with Atrial Fibrillation: A Report of the
American College of Cardiology Foundation/ American Heart Association Task Force on Practice. Circulation.2011; 123: e269-e367.
2.Wolf PA, et al. Atrial fibrillation as an independent risk factor for stroke: the Framingham Study. Stroke. 1991. 22: 83-988
3.Hohnloser SH, ASSERT Investigators and Committees, et al. Asymptomatic atrial fibrilla¬tion and Stroke Evaluation in pacemaker patients and the atrial fibrillation Reduction atrial
pacing Trial (ASSERT). Am Heart J. 2006 Sep;152(3):442-7.
4.Fuster V, et al. 2011 ACC/AHA/HRS Focused Updates Incorporated ino the ACC/AHA/ESC 2006 Guidelines for Management of Patients with Atrial Fibrillation: A Report of the
American College of Cardiology Foundation/American Heart Association Task Force on Practice. Circulation.2011; 123: e269-e367.
5.Wolf PA, Dawber TR, Thomas HE Jr, Kannel WB. Epidemiologic assessment of chronic atrial fibrillation and risk of stroke: the Framingham Study. Neurology 1978; 28(10):973-7.
6.Healey JS; ASSERT Investigators, et al. Subclinical atrial fibrillation and the risk of stroke. N Engl J Med. 2012 Jan 12;366(2):120-9.
7.Task force for the management of atrial fibrillation of the European Society of Cardiology. Guidelines for the management of atrial fibrillation. European Heart Journal.
2010;31:2369-2429.
8.Hart RG, et al.Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation. Ann Intern Med. 2007 Jun 19;146(12):857-67.
9.Attuel P, et al. Patients reported statistically significant improved QOL in 7 categories out of 9 in the SF-36 standard questionnaire. INOVA study. Europace Supplements. 2003; 4:
B66. Abstract A42-6.
10. Tendril™ FSR Model 1699T Lead Study PMA and Final Report (IDE#G050207).
11. ClinicalTrials.gov ID # NCT00911508.
12. ClinicalTrials.gov ID # NCT01014741.
13. Verma A, et al. Substrate and Trigger Ablation for Reduction of Atrial Fibrillation (STAR-AF): A Randomized, Multicentre, International Trial. Eur Heart J. 2010 Jun; 31(11): 1344-56.
14. ClinicalTrials.gov ID # NCT01056328.
15. Healey JS, ASSERT Investigators, et al. Subclinical Atrial Fibrillation and the Risk of Stroke. New England Journal of Medicine. 2012 Jan 12; 366:120-9.
ATRIAL FIBRILLATION
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Brief Summary: Prior to using these devices, please review the User’s Manual for a complete listing of indications, contraindications, warnings, precautions, potential adverse events
and directions for use.
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