14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-153

Effort polymorphic ventricular arrhythmias in patients affected by arrhythmogenic right ventricular cardiomyopathy

Barbara Bauce, Andrea Nava, Alessandra Rampazzo*, Luciano Daliento, Michela Muriago, Cristina Basso**, Gaetano Thiene**, Gian Antonio Danieli*.
Departments of Cardiology, *Biology and **Pathology, University of Padua, Italy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) has been demonstrated to be a myocardial disease genetically determined. Until now several disease loci have been identified in different chromosomes^1-4.

In particular in 1995 we studied a family affected by ARVC in which the disease locus was localized in chromosome 1q42-43⁵. In this family affected subjects presented the same clinical findings consisting in polymorphic ventricular arrhythmias (left and right bundle branch block morphology) provoked by effort. No arrhythmias were present at rest⁶.

The analysis of these effort polymorphic ventricular arrhythmias showed that the coupling interval of the initial premature beat was never short, because the first premature beat occurred after the end of the T wave. This is different from the cases reported by Leenhardt et al6. The QRS morphology was polymorphic both in the frontal and horizontal plane with right and left bundle branch block patterns and superior or inferior axis deviation. Thus we can presume that this arrhythmia originates from different areas of the ventricles. The QT interval and QT dispersion were normal at rest and during effort.

The familial history was characterised by a high incidence of sudden death (4 subjects); in all of them the death occurred during effort.

In the following years we identified other 4 families with the same clinical findings and the disease locus in chromosome 1q42-43. This lead us to consider this syndrome as a clinical variant of ARVC. Thus the clinical features of this syndrome are the following:

– effort polymorphic ventricular arrhythmias (or syncopal episodes);

– familial history of sudden death. In our five families there were 4 cases of sudden death and three cases of abortive sudden death;

– normal or slightly altered 12-lead ECG;

– absence of late potential at signal averaged ECG (SAECG);

– normal or only slightly increased right ventricular volume with normal global right ventricular function at 2D-echo and angiography. The abnormalities of the parietal wall are predominantly observed at the right ventricular apex and subtricuspid region. The trabecular architecture is always involved;

– good results with betablockers therapy were obtained in the follow-up (which ranges from 2 months to 12 years, mean 4.5 years).

Since the lesions are segmental and mostly involving the apex of the right ventricle, the diagnosis may be difficult and these ventricular arrhythmias are frequently considered idiopathic. Correct and early identification of this disease is crucial, taking into account the poor prognosis of patients with this arrhythmia. Thus the preselection of patients can be made with the exercise stress test which provokes the onset of ventricular arrhythmias with left bundle branch block and right bundle branch block morphology. Another important information is given by a familial history of sudden death or by the presence of syncopal episodes during effort. The diagnosis can be confirmed by the genetic analysis.

In all these patients a betablockers therapy is recommended; subjects are also strongly advised to restrict physical exercise.

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