RT-191
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Initial experience with the
implantable atrial defibrillator
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Werner Jung, Christian Wolpert,
Susanne Herwig, Susanne Spehl, Bahman Esmailzadeh*, Christian Schneider*, Heyder Omran,
Paul G. Kirchhoff*, Berndt Lüderitz.
Departments of Medicine-Cardiology and *Cardiovascular Surgery, University of
Bonn, Bonn, Germany
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Introduction
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The overall prevalence of atrial fibrillation (AF) in
the United States ranges from < 1% in young, otherwise healthy individuals up to nearly
9% in elderly patients. AF is a frequent and costly health care problem representing the
most common arrhythmia resulting in hospital admission. More than 179 000 patients were
hospitalized for AF at 678 hospitals in the United States in 1990. This group represented
more than one third of all admissions for arrhythmias. Total mortality and cardiovascular
mortality are significantly increased in patients with AF compared to controls. In
addition to symptoms of palpitations, patients with AF have an increased risk of stroke
and may also develop decreased exercise tolerance and left ventricular dysfunction. All of
these problems may be reversed with restoration and maintenance of sinus rhythm. Due to
the limited efficacy of antiarrhythmic drugs for AF, several non-pharmacologic options
have evolved including pacemaker therapy, transvenous catheter ablation techniques,
surgical procedures, and treatment with an implantable atrial defibrillator (IAD). The
development of an implantable cardioverter-defibrillator for the management of ventricular
tachyarrhythmias has stimulated investigation of a similar approach to AF1. A device for the management of recurring atrial
fibrillation should have several characteristics (Tab. I): low thresholds using only
transvenous electrodes, small size with several years of implant life, freedom from
ventricular proarrhythmia, a minimum of patient discomfort, limited thromboembolic risk,
high sensitivity and specificity for detection of atrial fibrillation2-5.
Furthermore, cost-effectiveness and improvement in quality of life have to be demonstrated
when such a device will be introduced for clinical management of patients with AF6.
TABLE I - Internal atrial defibrillation: specific considerations
Detection:
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sensitivity and specificity
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Efficacy:
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energy requirements
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Safety:
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ventricular proarrhythmia
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Patient tolerability:
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pain
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Thromboembolic risk:
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left atrial appendage function
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Quality of life:
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repeated shocks
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Cost-effectiveness:
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health reform
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