Signal averaged ECG is useful for early detection of cardiac involvement in Portuguese amyloidosis

Fernando Scazzuso MD., Horacio Aziz MD., Pedro Trigo MD., Javier Lendoire MD.,
Oscar Imventarza MD., Jorge Gonzalez-Zuelgaray MD.

Argerich Hospital.
Buenos Aires, Argentina.

Abstract
Amyloidotic familiar polineuropathy is a hereditary disease of dominant autosomal transmission. It is caused by an abnormal protein (transtiretine), which deposits in the nervous system, heart, spleen, kidneys, eyes and thyroid gland. Its curation is obtained by liver transplantation. At the cardiac level it produces an alteration in dyastolic relaxation, besides arrhythmias and conduction disorders.
Between March 1996 and May 1997, 4 family members were studied before liver transplantation (2 men and 2 women, aged 37-42 years).The cardiovascular exam and chest X-ray were normal. Nevertheless, the signal averaged ECG showed the following findings:
a) Abnormalities in the time domain analysis in all patients by the 3 standard criteria (LAS, RMS and QRS duration > 113 msec).
b) Decrease in the QRS filtered amplitude (*spectral mapping analysis of heart rate variability, there was a denervation pattern in 3 out of 4 patients.
In the fourth patient, the initial study was normal (62.12% of the spectral power in the 0.04-0.15 Hz range), while there was a de cxnervation pattern 12 months later.
In conclusion, signal averaged ECG and heart rate variability are sensitive markers of early cardiac involvement in amyloidotic familiar polineuropathy. These findings have not been reported previously.

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