Early Electrocardiographic Aging in
Down Syndrome Patients

Algimantas Sinkus, Irena Andriuskeviciute, Lina Jurkeniene

Kaunas University of Medicine, Kaunas, Lithuania

Correspondence: A Sinkus, Laboratory of Cytogenetics, Department of Biology, Kaunas University of Medicine,
Mickevičiaus 9, 3000 Kaunas, Lithuania.
E-mail: sinkus@vision.kmu.lt, phone +370 37 327 326, fax +370 37 220 733

1.    Introduction

We had chosen the method of familial ECG investigation in Down syndrome (DS) patients for detecting of ECG traits with prevalent inherited or environmental influences. We have found that for the appearance of three ECG signs – bundle branch block, tachycardia, and ventricular preexcitation – hereditary factors are responsible predominantly while other ECG disturbances are basically determined by environmental factors [Sinkus et al., 1997; Sinkus et al., 1999]. The same familial DS model we have also used in present investigation to detect, if the chromosome imbalance causes an increased ECG disturbances with aging.

2.  Material and Methods

Standard 12-lead ECG was recorded for all of 1004 DS patients and their relatives in regional hospitals. No clinical or cardiological investigations have been done for the patients as well as data of these investigations have not been used: except for a “familial” ECG diagnosis divided into 21 traits. The ECG were studied in a group of 297 DS patients (average age 14.1 yrs) with cytogenetically proven additional chromosome 21. ECG was also taken for 269 siblings (average age 18.7 yrs) and 438 parents (average age was 48.4 yrs for mothers and 49.6 yrs for fathers) with normal karyotype. The parents were older than DS patients in average 35.0 yrs, than healthy children – 30.2 yrs. We believed that age-depended ECG changes, if they exist between these three groups, would be revealed.

3.  Results and Discussion

ECG changes have been found in 77.7% of DS patients, 63.6% of siblings and 69.2% of parents. The increased frequencies for cicatrix, repolarisation abnormalities and low QRS voltage in parents as compared with healthy offsprings, were most likely due to aging. The DS patients, as compared with their siblings, showed an increased incidence of sinus tachycardia, bundle branch blocks and ventricle preexcitation.

In order to determine how varies the ECG changes considering of age, the sample was divided into age groups of five years (Table 1). The increased incidence of ECG pathology was observed in DS patients aged 30 yrs and beyond whereas in the parents it occurred much later, after reaching 70 yrs. The age-dependent incidence curve in siblings precisely corresponded to that of parents in the interval between 20 and 40 yrs, i.e. where the ages of both groups were overlapping. The life duration of DS patients is less than average. Up to 25 percent of the patients die during the first year of life due to severe congenital malformations [Castilla et al., 1998]; about 50 percent won’t live 60 yrs [Aquino et al., 1998]. Generally, these patients live shorter as their biological age is approximately double in comparison with healthy people [Nakamura and Tanaka, 1998]. Undoubtedly, the one of reasons in early mortality of chromosome patients must be connected with cardiac pathology. We assume that namely the electrocardiographic aging process of myocardium starts 40 years earlier as compared with their parents.

Table 1.    Age-depended frequency of ECG disturbances.

4.  Conclusions

4.1 The frequency of ECG changes among the patients with Down syndrome increases from the age of 31 years, and it does not increase for their healthy brothers and sisters.

4.2 The frequency of ECG changes in the parents increases from the age of 71 year, i.e. 40 years later than in the patients with Down syndrome.

4.3 The frequency of ECG changes of parents and their healthy offsprings coincide in the age interval of 20-40 years.

References

Aquino A, Domini M, Rossi C, Sardella L, Palka G, Chiesa PL. Correlation between Down’s syndrome and malformations of pediatric surgical interest. Journal of Pediatric Surgery, 79: 108-111, 1998.

Castilla EE, Rittler M, Dutra MG, Lopez-Camelo JS, Campana H, Paz JE, Orioli IM. Survival of children with Down syndrome in South America. ECLAMC – Down-sury group. Latin American collaborative study of congenital malformations. American Journal of Medical Genetics, 79: 108-111, 1998.

Nakamura E, Tamaka S. Biological ages of adult men and women with Down syndrome and its changes with ageing. Mechanisms of Ageing and Development, 105: 89-103, 1998.

Sinkus A, Andriuškevičiūtė I, Jurkėnienė L. Hereditary and non-hereditary pathology in ECG. Biomedizinische Technik, 42 (suppl.1): 148-150, 1997.

Sinkus A, Jurkėnienė L, Andriuškevičiūtė I. ECG in Down syndrome patients and their siblings. In Electrocardiology ’98 (Proceedings of the 25^th International Congress on Electrocardiology, Budapest, 1998), 1999, 427-430.