RT-197
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Inhomogeneous prolongation of
ventricular repolarization in young patients with repaired tetralogy of Fallot. Evidence
of electrical myocardial instability?
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Berardo Sarubbi, Giuseppe
Pacileo, Valentino Ducceschi, Carlo Pisacane, Carola Iacono, Maria Giovanna Russo, Lucio
Santangelo*, Aldo Iacono*, Raffaele Calabro.
Second University of Naples, *Chair of Cardiology, Paediatric Cardiology, Monaldi
Hospital, Naples, Italy
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Abstract
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Ventricular arrhythmias and sudden death have been
reported in patients with repaired tetralogy of Fallot (TOF). The aim of the study was to
examine ventricular repolarization time indexes, in terms of both absolute measures and
dispersion across the myocardium in young patients operated on for TOF (32 pts; 19M and
13F, age 11.1 ± 3.4 years; age at surgery 2.4 ± 1.2 years, duration of follow-up 8.5 ±
3.3 years), as these electrocardiographic parameters have shown to be effective in the
identification of electrical myocardial instability and hence in the identification of
risk for ventricular arrhythmias. Furthermore, it has also been investigated the possible
influence on ventricular repolarization of known negative prognostic factors relative to
the surgical approach, age at intervention, and presence of pulmonary obstruction and/or
regurgitation. For this reason patients in the study group were divided in two subgroups
in relation to the presence of zero-one (group low-risk: 15 pts; age 11 ± 2.9 years) or
more than one (group high-risk: 17 pts; age 11.1 ± 3.9 years) negative prognostic factor.
Their data were compared with those of 22 age-matched asymptomatic control subjects (14M
and 8F, age 12 ± 1.5 years). All the patients of the study group revealed complete right
bundle branch block and, from the analysis of ventricular depolarisation, as expressed by
QRS duration, emerged that it resulted significantly longer in total Fallot group and in
each subgroup than in the control group. All the pts operated on for TOF exhibit, with
respect to control subjects, an inhomogeneous prolongation of ventricular repolarization
across the myocardium, as showed by the significant increase in the absolute indexes of
recovery time, JTc, QT and QTc with a concomitant prolongation of the indexes of
dispersion time, QTcD, JTcD, "adjusted" QTcD, and Tp-Te interval. These findings
could, in part, explain the mechanisms that contribute to the development of ventricular
arrhythmias in patients with surgically repaired TOF, as this dispersion of refractoriness
has been widely accepted as a predisposing factor in the development of ventricular
re-entry tachyarrhythmias.
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Key Words
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Peadiatric arrhythmias- management
ventricular repolarization time indexes, tetralogy Fallot post-operation patients,
electrical myocardial instability, ventricular arrhythmias, sudden death, ventricular
recovery time indexes, OA
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