RT-79
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Role of multisite mapping in
catheter ablation of atrial fibrillation
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Annibale Sandro Montenero,
Anselma Intini, Maria Grazia Bendini, Gemma Pelargonio, Katia Martini, Paolo Zecchi.
Istituto di Cardiologia, Universita Cattolica del Sacro Cuore, Rome, Italy
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Introduction
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It is necessary to map the activation in the heart in
order to distinguish between the various tachyarrythmias. These arrythmias are
differentiated by the number of reentrant circuits, their stability, their cycle length
and propagation away from the circuits.
Cardiac tachyarrhythmias are broadly characterized as being dependent upon
abnormalities of impulse formation (automatic, ectopic) versus impulse conduction
(reentrant). These two mechanisms of arrhythmogenesis give rise to a broad range of
distinct arrhythmias which have different prognosis and respond to different treatments.
Therefore, the unique classification of an individual's arrhythymia has both prognostic
and therapeutic implications.
In addition to this dichotomy of mechanism, there is a dichotomy of localization of
origin, as atrial tachyarrhythmias may be either focal in origin (ie, activation appears
to stem from a single area as in focal atrial tachycardia) or macro-reentrant with
activation sweeping in a continuous identificable circuit with no clear origin or terminus
(as in atrial flutter). Identifying the mechanism and localizing the origin of
tachyarrhythmias frequently requires recording electrical activity from multiple locations
within the atria or the ventricles, characterizing the sequence of activation, and
analyzing the changes in cycle length and activation sequence which occur in response to
pacing protocols (often from multiple locations).
Several approaches to multisite mapping exist, each with its own limitations.
Multisite mapping for atrial tachycardias has been used extensively in the operating room.
The obviuos drawbacks of the operative mapping technique are the cost, discomforts and
risks of a highly invasive surgical procedure. Additionally, intraoperative mapping is
limited by the origin of the tachycardia in some patients because of the suppressive
effects of anesthesia or hypothermia. Radiofrequency chateter ablation techniques have
emerged for potential curative treatment of atrial tachyarrhythmias without surgery. Thus,
the use of multiple transvenous mapping catheter techniques has emerged to capture
information regarding cardiac activation without the concomitant surgical risks. Although
right atrial mapping can be facilitated with the use of a two-catheter ("dancing
catheter tecnique") method, the deployment of multiple mapping catheters sometime may
be necessary to define a large macro-reentrant area or to find the location of a focal
atrial tachycardia.
To map the target arrhythmia with the Multipolar Mapping Basket Catheter may allow
more rapid acquisition of intracardiac electrograms than mapping using conventional single
mapping techniques. This would be advantageous in patients whose arrhythmia is
non-sustained or haemodynamically unstable.
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Key Words
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Atrial fibrillation
catheter ablation, multisite mapping of activation, Multipolar Mapping Basket Catheter, R
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