Download conduction abnormalities in arrhythmogenic right

CONDUCTION ABNORMALITIES IN ARRHYTHMOGENIC
RIGHT VENTRICULAR CARDIOMYOPATHY
Stefan Peters - St.Elisabeth Hospital Salzgitter, Cardiology, Germany
According to an article of Tabib et al., published in 2003, in more than 60% of cases
fibrosis was found within structures of the conduction system of 200 autopsy cases
with arrhythmogenic (right ventricular) cardiomyopathy-dysplasia (ARVC-D). The
question is whether conduction abnormalities belong to the electrocardiographic
spectrum of ARVC/D.
Method: The very first ECG without medication was analysed with regard to
conduction abnormalities (AV block 1° or 2° or 3°), right bundle branch block or
need for pacemaker implantation of 376 patients with modified ISFC/ESC criteria of
ARVC-D (210 males, mean age 46.4 ± 11.7 years).
Results: Symptomatic AV block II° and III° were present in 6 patients and in
additional 3 patients with provocable electrocardiographic Brugada pattern. A
complete right bundle branch block as the initial electrocardiographic finding was
found in 5 patients. Only nine patients presented with AV-block I°. The incidence of
conduction abnormalities and complete right bundle branch block was only 6 %.
Conclusions: The rate of fibrosis of the conduction system as described in the paper
of Tabib cannot be confirmed, as the incidence of conduction abnormalities in only
6%. Fibrofatty changes of the conduction system were found in 7% of cases which
correspond to the rate of conduction abnormalities. This finding can be seen in the
light of rare non-desmosomal gene mutations encoding lamin A/C, titin, TMEM
protein 43 and possibly cardiac sarcoidosis mimicking ARVC/D. Complete right
bundle branch block is possibly the result of rare desmin gene mutations.
AV block I° is more prevalent in Brugada syndrome and belongs to the
electrocardiographic spectrum of this syndrome in SCN5A mutations.