Prevention of cardiovascular disease: an urgent Canadian problem Cardiovascular disease causes over half the deaths in Canada each year. The estimated economic drain ($1 to $2 mil¬ lion per year) through lost wages and productivity is staggering. What is being done to control this epidemic? Are there regional disparities in the de¬ tection and prevention of heart dis¬ eases? And if so, are they the result of misplaced priorities and lack of lead¬ ership by both the medical profession and health care professionals? Sound programs for cardiovascular rehabilitation and physical fitness should be established in all parts of Canada if we are to prevent or reduce the massive disability due to heart dis¬ ease. The federal government has al¬ ready generated much enthusiasm for health and exercise programs by its ef¬ forts to promote physical fitness and to reduce cigarette smoking. However, it is almost impossible for those citi¬ zens wishing to start such a program to have a check-up that includes a

supervised electrocardiographic exer¬ cise test. Perhaps our profession is not aware of the immensity of the prob¬ lem. We are too hospital- and diseaseoriented in our current health care delivery system. We do not stress pre¬ vention. Indeed, we hardly pay lip serv¬

ice to it. Little accurate information is avail¬ able on the state of health of Cana¬ dians. Where are the myocardial infarc¬ tion registers and hypertension registers established in so many European coun¬ tries? Even Finland (population, 4.5 million) has started a program to detect and control cardiovascular disease in a region of 186 000 people. In contrast with such European efforts and the massive national clinical trials in the United States,1 what are we doing in Canada? Without such programs how can we

urge

prevention

or even

plan

for it? Even in the field of hypertension Canadian studies are few. (One of the best of these was by Silverberg and colleagues in this journal in October 1974.2) Over 3 million Canadians are hypertensive; less than 50% are aware

of their disease and less than 20%

are

before

a

program of detection and

receiving adequate treatment.3 And control of cardiovascular disease is ini¬ these estimates are based mainly on US tiated. However, in view of the epi¬ statistics since none are available for demic proportions of cardiovascular Canada. We must mount a massive de¬ disease in this country, should we wait tection and prevention program imme¬ any longer? Detection and prevention diately and provide follow-up measures programs could be established now and with individualized instruction and care integrated into the computer-based to prevent strokes, kidney failure, heart health information system as it de¬ failure and heart attacks. And the most velops. We need to establish a "demonstra¬ economical ways. to detect and control cardiovascular disease are computeriza- tion" study within the context of an tion of health data and analysis of the organized health care delivery system electrocardiogram (ECG) by computer. to prove and evaluate the new tech¬ Assessment of cardiovascular health nology for the prevention of cardiovas¬ without an ECG is perilous. Without it, cular disease. Such a computer-communication study involving a "demon¬ we will never effectively attack coro¬ nary artery disease and its associated stration" population of 50 000 to conditions. The ECG is the most re¬ 100 000 would provide a base of con¬ liable objective indicator of the progres¬ fidence for the broader benefits accrusion or regression of coronary artery ing from a computerized lifetime health disease and hypertension.4 Even more profile. Such a proposal focuses atten¬ important, a baseline ECG may in¬ tion on the problem of individual dicate disease simply because there has privacy and access of the consumer to been a change, though the readings are his own data. The latter problem may still within normal limits: a shift in be solved easily by requiring that all axis,5 a change in ST segment or an information be available to the indivi¬ alteration in T wave and QRS pattern, dual. Privacy for research purposes can maintained by withholding names though still within normal limits, may be indicate cardiovascular disease. Com¬ and other identifying data. The terms puter programs are more accurate and of reference should stipulate that in¬ formation identifying a person would are able to detect myocardial infarction earlier than the experienced cardiolo- not be released except by permission of Most insurance compa¬ gist6 (one of every four myocardial in¬ that individual. farctions is silent or is uncovered nies, for example, require such a re¬ only by the ECG7). Cardiologists often lease as a condition of providing the find it difficult to assess borderline ST proposed service. Statutory require¬ segment abnormalities, but knowledge ments can implement any decision of the patient's baseline ST profile over made about third-party release, but these requirements must include the a period of years may prevent unneces¬ sary hospitalization. The ECG can basis on which information is held and identify those patients at high risk for released by the third party. Consumer heart attacks, so the need for this type groups (and others) should determine of examination is urgent. Computer the statutory requirements for thirdanalysis of the ECG can select those party release. Once such a basis is who are at high risk and thereby re¬ agreed upon, an ombudsman mechan¬ duce the costs of individual counselling ism would enable individuals to ques¬ tion and appeal any suspected misuse on nutrition, smoking, management of hypertension and physical fitness in the of information. general population. Computer-communication links will It has been suggested that a gen¬ provide important improvements in eralized computer-based health infor¬ health care delivery: the expertise of mation system should be in effect the specialist will be available to the CMA JOURNAL/FEBRUARY 7, 1976/VOL. 114 185

remote areas of Canada; practice in such areas will be more attractive to young physicians; and once radiotelemetry of cardiovascular data is available, patients will receive expert care locally without expensive transport to major medical centres. We are being left far behind in the prevention of cardiovascular disease. We have the expertise in computerization and epidemiology and yet little is being done. Let us attack the problem before the heart attack stops us.

J.A. MILLIKEN, MD

Department of medicine Queen's University Kingston, ON

3. GENEST J: The hypertensive patient (E). Thid, p 747 4. MCCAUOHAN D, LITTMANN D, PIPRERGER HV:

P.M. RAUTAHARJU, MD, PH D

Biophysics and bioengineering research laboratory Faculty of medicine Daihousie University Halifax, NS

5. 6.

References 1. WiLsas JA, BARROW JG: Hypertension - a community program. Am J Med 52: 653, 1972

7.

2. SILVERBERO DS, SMITH ESO, JucHLI B, et al:

8.

Use of shopping centres in screening for hypertension. Can Med Assoc J 111: 769, 1974

Computer analysis of the orthogonal electrocardiogram and vectorcardiogram in 939 cases with hypertensive cardiovascular disease. Am Heart 1 85: 467, 1973 FERRER MI: The significance of axis deviation (E). Chest 61: 443, 1972 PIPSERGER HV, MCCAUGHAN D, Lr[TMANN D, et al: Clinical application of a second generation electrocardiographic computer program. Am I Cardiol 35: 597, 1975 KANNEL WB, MCNAMARA PM, FEINLEIB M, et al: The unrecognized myocardial infarction. Fourteen-year follow-up study in the Framingham Study. Geriatrics 25: 75, 1970 BONNER R: Computerized interpretation of ECG. Paper presented at the 1975 Engineering Foundation Conference, Rindge, New Hampshire

The future is now The catch phrase, "the future is now", which was used during a recent provincial election campaign, is also pertinent to the practice of medicine. Are some of the health problems facing us today the result of iatrogenic medicine practised by our predecessors? Are we just as guilty of creating problems for those who follow us? I believe the answer to both questions is "Yes". Two examples are the common use of diethylstilbestrol (DES) and the widespread, loose reliance on radiographs. Several years ago The Canadian Medical Association expressed concern over the continued prescription of DES, particularly as a postcoital contraceptive. This concern was expressed in other countries because the presence of vaginal adenosis and malignant lesions in the teenage daughters of women given DES in early pregnancy appeared to be increasing. A recent study in the United States showed that a high percentage of male offspring of mice given DES in early pregnancy had reduced sperm count and motility, and in some cases complete sterility.' Health and Welfare Canada directed that DES should not be considered as a postcoital contraceptive except in cases of rape or incest, yet some physicians still prescribe the drug in cases of possible pregnancy when an abortion is unlikely to be performed should estrogen not produce bleeding. In 1972 a CMA committee was formed to examine radiation hazards. Included on this committee were representatives from the health programs branch and the radiation protection bureau of Health and Welfare Canada, The Canadian Association of Radiologists, the Canadian Public Health Association, the Canadian Thoracic Society and the Canadian Tuberculosis and Respiratory Disease Association. The recommendations made by the committee, which were approved by

General Council in 1973, indicated that routine screening should not be carried out, except in special circumstances and where applicable to certain high-risk segments of the population. But physicians still order routine chest radiographs, as do life insurance companies and certain industries; hospitals whose regulations require a routine admission radiograph are also guilty. Over 60% of Canadians with access to modern medical and dental care are exposed to some form of radiography each year. Experts believe that well designed and properly used medical x-ray equipment could reduce unnecessary exposure to about 10% of its present level without loss of diagnostic information. Epidemiologic studies have linked radiation to certain conditions: carcinogenesis, accelerated ageing, genetic changes and blood dyscrasias. In the US a study2 by the National Academy of Sciences suggested that x-rays cause 4000 deaths in that country each year. Dentists and chiropractors also contribute to this major health hazard. Does your dentist protect your child's body, particularly the gonadal area, from x-rays with a lead apron? And how many women are exposed to dental x-rays in early pregnancy without protection? Reliable authorities believe that the "14 x 36 full-trunk x-ray", so beloved by the chiropractor, presents one of the greatest radiation hazards, and published figures show that chiropractors subject over 90% of their patients to this type of exposure. Obviously patients, particularly children and women in the reproductive age group, receive minimum protection, and no steps are being taken to reduce the hazard. Physicians should be aware of, and concerned about, radiation procedures carried out by their predecessors. The work of Stewart and associates3 in the United Kingdom, linking childhood

186 CMA JOURNAL/FEBRUARY 7, 1976/VOL. 114

leukemia with prenatal maternal radiation, is well documented. Not as well known is the documented evidence of malignant thyroid lesions appearing in adults 20 to 30 years after radiation exposure of the head, neck and upper thorax.4 Several articles have emphasized the need for physicians to review their files and patients' histories for evidence of such exposure so that these patients may be followed up.5'6 In a study of operations for thyroid carcinoma in adults the University of Chicago thyroid study unit found that in 40% of such cases the patient had a history of neck irradiation.4 Scientists have expressed the view that about 40 rads is the upper limit of safety for total body exposure during an average lifetime. This estimate excludes therapeutic radiation, as might be given in treatment of malignant conditions. It is important that we do everything possible to minimize health hazards to future generations. Our whole approach to man-made health and environmental hazards should be carefully examined so that primum non nocere becomes more than a cliche. JOHN S. BENNETr, MD

Coordinator, Council on Community Health The Canadian Medical Association

References 1. McLACHLAN JA, NEWBOLD RR, BULLOCK B: Reproductive tract lesions in male mice exposed prenatally to diethylstilbestrol. Science 190: 991, 1975 2. Advisory committee on the biological effects of ionizing radiations, National Academy of Sciences/National Research Council: The Ef-

fects on Populations of Exposure to Low Levels of Ionizing Radiation, Washington, US Dept of Health, Education and Welfare! Environmental Protection Agency, 1972

3. STEWART A, WEBB J, GILES D, et al: Malignant disease in childhood and diagnostic irradiation in utero. Lancet 2: 447, 1956

4. DEGRoo.r L, PALOYAN E: Thyroid carcinoma and radiation. A Chicago endemic. JAMA 225: 487, 1973

5. REFETOFF 5, HARRISON J, KARANFIL5KI BT, et al: Continuing occurrence of thyroid carcinoma after irradiation to the neck in infancy and childhood. N EngI J Med 292: 171, 1975

6. BRAVERMAN LE:

Consequences of thyroid

radiation in children (E). Ibid, p 204