Stefano Favale, Ursula Appl*, Frida Nacci, Luciano Sallusti**, Luigi de Luca Tuppati Schinosa.
Arrhythmia Service-Cardiosurgery,
Unit-Department of Emergency and Transplantation, University of Bari, Italy, *Guidant Europe, **Guidant Italy
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Dual-chamber implantable
cardioverter-defibrillator may allow advantages in managing patients at risk of
tachyarrhythmic death favouring a reduction of inappropriate interventions due to
atrial tachyarrhythmias, a greater hemodynamic stability and a more appropriate
stimulation in cases with the evolution toward bradycardia and/or atrio-ventricular
block.
The algorithm using atrial sensing can increase specificity in ventricular tachycardia
recognition while atrial pacing can provide better atrial electrical stability which can
be further increased by drugs.
In patients with severe left ventricular dysfunction an improvement in left ventricular
function obtained by dual-chamber stimulation, eventually biventricular, could
determine a reduction in non-sudden deaths and prolong life expectancy. DDD pacing
in these cases is thought to provide adequate chronotropism, optimal delay in the
atrio-ventricular sequence, a more adequate left ventricular volume, higher atrial
stability and to allow a wider use of betablockers.
Moreover, while the need for pacing may not seem necessary at the time of
cardioverter-defibrillator implantation, the serious cardiac pathology present in the
majority of patients with ventricular tachyarrhythmias can be complicated after
implantation by sinus node dysfunction or atrioventricular block.
In patients with left ventricular dysfunction and indication for implantable
cardioverter-defibrillator, not needing pacing and taking carvedilol, a prospective
and randomized comparison is proposed: consistent DDDR implantable
cardioverter-defibrillator vs back-up DDI implantable cardioverter-defibrillator.
The primary objective of the study is to demonstrate that the occurrence of atrial
tachyarrhythmia is reduced by DDDR consistent pacing compared with back up DDI
pacing. Secondary objective is to register embolic events, ventricular arrhythmias,
hospitalization due to cardiac causes, quality of life score, sudden cardiac deaths,
non sudden cardiac deaths and all cause mortality.
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