ELECTROCARDIOGRAPHIC ALTERATION AMONG 1ST-DEGREE RELATIVES WITH SEROLOGIC EVIDENCE OF TRYPANOSOMA INFECTION - A SIBSHIP STUDY

To analyze whether electrocardiographic alterations (ECGA) in patients with antibodies to Trypanosoma cruzi showed a pattern of familial agg regation, a sample of 379 young adults (166 men and 213 women) distrib uted in sibships, were assessed for the presence of anti-T.cruzi antib odies, and subjected to a complete clinical examination and a standard resting electrocardiogram (ECG). Positive T. cruzi serology was detec ted in 165 individuals, 48 of them showing an abnormal ECG (overall pr evalence 29%). One hundred and eleven seropositive individuals were di stributed in 45 sibships, each of them constituted by more than one se ropositive sib, with ECGA being present in 34 out of these patients. S eropositive subjects with ECGA were detected in 27 sibships Since the index case within each sibship is counted exactly once, affected indiv iduals selected at random as propositi were extracted to calculate the prevalence of ECGA among first degree relatives of probands. Abnormal ECGs were recorded in 7 out of 45 sibs yielding a prevalence that did not differ from estimations registered in the general population or s eropositive sibs. Data from the present sample show no familial aggreg ation for the occurrence of ECGA in patients with T.cruzi infection.