The incidence of congenital heart disease (CHD) in the Western industrialized world has varied from a low value of about 3 to 5 per 1000 live births to about 12 per 1000 live births. Most of the lower incidence figures were obtained before there were sufficiently well trained pediatric cardiologists and before the success of cardiac surgery put a premium on early and correct diagnosis of CHD. The advent of echocardiography with Doppler color flow measurements has made it possible to diagnose lesions that are asymptomatic, minor, and even without murmurs. Given these differences, there does not appear to have been a significant increase in the incidence of CHD over the last 20–30 years. The incidence of CHD in underdeveloped countries is not known, but the distribution of different lesions is fairly similar to those in developed countries except perhaps for fewer with aortic stenosis and coarctation of the aorta.

https://link.springer.com/content/pdf/10.1007/BF00801907.pdf

Incidence of congenital heart disease: I. Postnatal incidence

The Child Health and Development Studies are longitudinal studies of pregnancy and the normal and abnormal development of the offspring. Women who were membres of the Kaiser Foundation Health Plan entered the study in early pregnancy, and their children were examined frequently until the youngest child in the study was 5 years old. This is a more intensive follow-up than hitherto reported. Of the 19,044 live-born children, 163 had definite and another 31 had possible congenital heart disease; the crude incidence rates per 1,000 live births were 8.8 for definite congenital heart disease and 10.4 for definite plus possible congenital heart disease. The incidence rate of congenital heart disease was 7.9 percent among all stillborn fetuses subjected to autopsy and 10.2 percent among those in this group with autopsies evaluated as being detailed enough to detect heart disease. Among the live-born children with congenital heart disease, 21 died in the neonatal period and 22 died in later infancy and childhood; about half the deaths were judged to have been due to heart disease. About 30 percent of the children with congenital heart disease had associated severe anomalies of other systems. In the whole cohort, 50 children had diagnosed chromosomal abnormalities (2.63/1,000 live births) and about 30 percent of them had congenital heart disease. Among the group of 163 children with definite congenital heart disease, the diagnosis was made in 46 percent by age 1 week, in 88.3 percent by age 1 year and 98.8 percent by age 4 years.

Congenital heart disease in a cohort of 19,502 births with long-term follow-up

Maternal insulin-dependent diabetes has long been associated with congenital malformations. As other causes of mortality and morbidity have been eliminated or reduced, malformations have become increasingly prominent. Although there is not universal agreement, the great majority of investigators find a two- to threefold increase in malformations in infants of insulin-dependent diabetic mothers. This increase is not seen in infants of gestational diabetics. It probably is not present in women whose diabetes can be controlled by diet or oral hypoglycemic agents. The risk does not appear to be primarily genetic since diabetic fathers do not have an increased number of malformed offspring. Most studies show a generalized increase in malformations involving multiple organ systems. Multiple malformations seem to be more common in diabetic than non-diabetic infants. Caudal regression has the strongest association with diabetes, occurring roughly 200 times more frequently in infants of diabetic mothers than in other infants. The teratogenic mechanism in diabetes is not known. Hyperglycemia may be important but human studies focusing on the period of organogenesis are lacking. Hypoglycemia has also been suggested based mainly on animal experiments. Insulin appears unlikely. Numerous other factors including vascular disease, hypoxia, ketone and amino acid abnormalities, glycosylation of proteins, or hormone imbalances could be teratogenic. None has been studied in sufficient detail to make a judgment. A large-scale prospective study is required to determine early fetal loss rates, correlate metabolic status during organogenesis with outcome, and assess the effect of diabetic control on malformation rates.

Malformations in Infants of Diabetic Mothers

OBJECTIVE To predict the growth in demand for long term follow up of adults with congenital heart disease. DESIGN Observed diagnoses of congenital heart disease in infancy and childhood were adjusted for observed infant survival, predicted further survival to age 16 years, underascertainment in older childhood, and predicted need for long term follow up. SETTING The resident population of one health region in the UK. PATIENTS All confirmed cardiovascular malformations diagnosed in 1985 to 1999 in children born in 1985 to 1994. RESULTS 1942 cases of congenital heart disease were diagnosed in infancy in a population of 377 310 live births (5.2/1000). 1588 (82%) survived to 1 year and 1514 were predicted to survive to age 16. 605 further diagnoses were made in childhood—678 when adjusted for underascertainment. Thus, 2192 children were predicted to reach age 16, of whom 784 would require long term follow up in adult life. The adult population would comprise 28% complex, 54% significant, and 18% minor congenital heart disease. These figures predict the need for adult follow up of congenital heart disease of over 200 extra cases per 100 000 live births each year or over 1600 extra cases a year every year in the UK. CONCLUSIONS The need for follow up of congenital heart disease in adult life is likely to grow linearly, with increasing complexity and increasing need for reinvestigation and reintervention with time. Appropriate provision should be made for adequate manpower, resources, and facilities for care of these patients.

https://heart.bmj.com/content/heartjnl/85/4/438.full.pdf

Survival with congenital heart disease and need for follow up in adult life

A spread-spectrum technique for cellular high-capacity mobile communications is described and some results from an analytic study are summarized. The technique uses a very large set of frequency-hopped signals which are designed for minimal mutual interference. No synchronization of the mobile units is required, and each user is permanently assigned his own signal, which serves as an identifying signal and as a carrier for the biphase-modulated digital message. The spectral efficiency of the spread-spectrum system is analyzed and compared with the efficiencies of developmental FM/channel reuse schemes currently under construction in the U.S. and Japan. It is concluded that even with relatively simple speech digitization schemes, the efficiency of the spread-spectrum scheme may exceed those of the narrow-band schemes by a factor of almost five. More ambitious bit-rate-reducing speech digitization methods could improve still further on these figures. Additional benefits of the spread-spectrum scheme include immunity from fading and interference, more consistent speech quality, simpler system control algorithms, and more flexible blocking properties under overload conditions.

A spread-spectrum technique for high-capacity mobile communications

From a prospective study of 56,109 total births some incidence factors and etiologic correlates for congenital heart disease have been identified. The risk of congenital heart disease in infants with Down's syndrome was found to be 1:3, for the offspring of mothers with congenital heart disease 1:20, for the offspring of diabetic mothers 1:39, and for twin infants 1:61. Data from the offspring of mothers with congenital heart disease and from offspring who are twins or siblings of twins suggest that there may be a relatively large element of inheritance in the etiology of pulmonary stenosis. The risk of a great vessel abnormality for offspring of diabetic mothers is reaffirmed. The role of maternal age in the production of congenital heart disease in the offspring is assessed, and several correlates of transposition of the great vessels are identified. Preliminary data are presented on the association of maternal viral infection with congenital heart disease in the offspring.

Etiologic correlates in a study of congenital heart disease in 56,109 births.

PCM/NRZ systems operating in the presenceof noise and in a band-limited channel areconsidered. Two types of bit detectors arestudied, integrate and dump, and sample. Theincreased signal power needed to give thesame performance as an optimum detectorand a broad-band channel is computed. Theresults depend on the bit pattern. The averageeffect of band-limiting over all bit patternsand two extreme cases are plotted for eachdetector. The results show that integrate anddump is always superior to sample and that ifthe sample detector is used, one should bandlimit before sampling at a frequency of 0.6times the bit rate.

Effects of Band Limiting on the Detection of Binary Signals

The combined effect of cochannel interference and nonselective Rayleigh fading on the reception of analog FM signals in additive Gaussian noise is analyzed. Rice's click model for the breaking region is used. Analysis in the absence of interference is performed first and the effect of modulation on the click rate is found to be nearly negligible. For the case with cochannel interference the click rate is computed in the absence of modulation. Curves are given for detected signal-to-noise ratio (SNR) versus carrier-to-noise ratio (CNR) with signal-to-interference ratio (SIR) as a parameter and SNR versus SIR with CNR as a parameter. The results agree well with recently published results of a simulation study.

Effect of Fading on FM Reception with Cochannel Interference

In data transmission systems using electromagnetic propagation there is often interest in the antijam capability of the system and the probability that the transmitted signal can be intercepted. It is shown that, neglecting antenna gain, both of these are adequately described by the processor gain. An information theoretic bound is given for the processor gain and the performance of several conventional signaling systems is indicated. Improvement using forward error correction is also investigated.

J. H. Park

Papers

Etiologic correlates in a study of congenital heart disease in 56,109 births.

Effects of Band Limiting on the Detection of Binary Signals

Effect of Fading on FM Reception with Cochannel Interference

A Bound on Processor Gain