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Material
We recorded 12-lead ECG in 74 consecutive patients (63 men, 11 women) referred for
symptomatic VT due to ARVD. Right ventricular disease was documented in all cases by
cineangiography showing localized abnormal kinetics of the right ventricular wall in 61
cases, and a diffuse dilatation with an increased right ventricular end-diastolic pressure
in the remaining 13. Sustained monomorphic VT were documented in 59 patients, and
non-sustained VT in 15. Mean age at the first VT attack was 37.2 ± 13.5 years.
SA-ECG was prospectively performed in 54 consecutive patients with ARVD (46 men, 8
women) aged 38.2 ± 10.4 years. Right ventricular angiography shows a diffuse form in 16
patients and a localized one in 38. Sustained monomorphic VT was present in 34 patients,
whereas the remaining 20 had non-sustained VT.
Methods
We evaluated 12-lead ECG in terms of QRS duration and axis, presence of an epsilon
wave, incomplete or complete right bundle branch block (RBBB). Repolarization
abnormalities and right atrial hypertrophy were looked for.
SA-ECG used the Predictor system of Corazonics, recording 2-800 sinus beats on Frank
leads X, Y, Z, with an automatic rejection of ectopic and noised beats. The residual noise
after acquisition was always < 0.60 µV. Bidirectional filters between 40 and 300 Hz
were used. Normal values in time-domain were evaluated in 45 normal subjects of various
ages by calculating the limit of the one-tailed 95% confidence interval of the population
for each parameter. The length of QRS after averaging was 96.8 ± 8.6 ms and the limit of
normality was > 113 ms. The length of low amplitude signal (LAS) below 40 µV
was 28.4 ± 5.4 ms with a limit at > 38 ms. The root mean square of the last 40
ms (RMS40) was 47.3 ± 25.4 µV with a limit calculated after logarithmic transformation
at < 16 µV. Patients with at least 2 abnormal parameters out of these 3 were
considered as having late potentials (LP).
Follow-up
Initial 12-lead ECG was repeated during the follow-up in 36 cases, providing a total
of 110 ECG tracings, and in 14 patients, we had the opportunity to repeat SA-ECG giving a
total of 68 SA-ECG tracings available for correlation with age or duration of the
follow-up from the first VT.
Statistical analysis
Comparison between groups of ARVD patients according to clinical characteristics used
unpaired t-test. Changes in 12-lead and SA-ECG during the follow-up were appreciated by
correlation with age and time elapsed from the first VT.
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