RT-121
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Interatrial septum pacing: an
echocardiographic evaluation
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Giuseppe Barletta, Maria Cristina
Porciani, Riccarda Del Bene, Antonio Michelucci, Andrea Colella, Luigi Padeletti.
Istituto di Clinica Medica e Cardiologia, University of Florence, Italy
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Abstract
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Background and Aim. Permanent pacing
of the interatrial septum at the Koch triangle level, that may help preventing atrial
fibrillation, influences the sequence of atrial contraction with possible effects on the
atrial contribution to ventricular filling. The study aim was to verify whether
interatrial stimulation influences the chronology of right and left atria contraction and
the hemodynamic performance in patients with normal hearts.
Methods and Results. Among 30 patients who received an interatrial
septum dual-chamber pacemaker (19 men, age range 47-87), 9 patients (6 men, age range
47-83) with normal cardiac morphology and function (mean ejection fraction 0.60 ± 2)
underwent a complete Doppler echocardiographic study focusing on the chronology of onset
and the duration of the late diastolic atrioventricular flow waves (mitral and tricuspid
A-waves). The patterns during DDD and VDD pacing were compared. Tricuspid A-wave began
before mitral A-wave in VDD mode, while the sequence was opposite in DDD mode. The
tricuspid-to-mitral late flow onset interval was 21 ± 22 ms in VDD and -39 ± 20 ms in
DDD (p < 0.0005). The duration of the mitral A-wave had a trend towards an increase
(186 ± 37 vs 199 ± 39 ms, VDD vs DDD) while tricuspid A-wave duration trended to
decrease (196 ± 57 vs 180 ± 42 ms). Cardiac index was significantly higher in DDD mode,
due to a higher heart rate.
Conclusions. Our data indicate that interatrial septum stimulation
lets selectively modulate the left ventricular filling, making it possible to select a
short atrioventricular interval without interfering with the atrial contribution to left
ventricular filling. This could lead to overcome the delay in left atrial systole induced
by delayed interatrial conduction and may help managing cardiac failure when a very short
atrioventricular interval is indicated.
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Key Words
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Pacing assessment – follow-up
interatrial septum dual chamber pacemaker, VDD pacing, DDD pacing, optimal
atrioventricular delay, Doppler echocardiography, OA
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