First myocardial infarction in a Dutch general practice population: trends in incidence from 1975–2003

BACKGROUND: As morbidity registrations generally do not make distinct first and following myocardial infarctions, it is still unclear as to what extent the falling rates of myocardial infarctions are caused by lower incidences of first myocardial infarctions. AIM: To investigate the incidence of first myocardial infarctions in a general practice population. METHOD: Data were taken from the Continuous Morbidity Registration (CMR) Nijmegen, which has been collecting data from four general practices since 1971. For the 1975-2003 period, sex-specific and age-specific yearly incidence rates were obtained from the registration data of the CMR. Trends were studied with Poisson regression. RESULTS: During the study period, 827 patients with a first myocardial infarction were identified. The incidence of first myocardial infarctions has declined since 1986 to 2.1 per 1000 for men and to 1.5 per 1000 for women. The average age of getting a first myocardial infarction increased with 3 years for men and slightly decreased for women. Since 1986, the incidence of sudden cardiac death from a first myocardial infarction has considerably declined for men and women to 0.9 and 0.7 per 1000 respectively. CONCLUSION: A slight, significant, decline in incidence of first myocardial infarctions was found. From the mid eighties a mean annual decline of 3.5% in death from first myocardial infarction was observed. Though the variance in rates of coronary heart diseases is not unambiguous, this may indicate an effect of primary prevention. The decline was more pronounced in men, with an increasing age of getting a first myocardial infarction.     

The natural history of angina in a general practice

An appreciation of the natural history of angina pectoris is important when deciding on the place of new and potentially dangerous forms of treatment. During 1950-1975, 268 patients with angina were diagnosed and followed up in my London general practice. The annual incidence, in adults over 40, was five per 1,000 and increased with age.

During the period of follow-up, half the patients died, an annual mortality of 4·6 per cent. However, among the survivors one third ceased to suffer anginal symptoms spontaneously and without specific therapy. Of those who continued to suffer from angina, in 71 per cent the condition was graded as minor, in 27 per cent as moderate, and in only two per cent were the attacks severe and disabling. Usually the angina was primary (77 per cent) and it was secondary, after myocardial infarction, in 23 per cent.

Of the 134 deaths, three quarters were from a cardiovascular cause. This group of angina patients had a 2:1 times greater observed, than expected, risk of dying (O/E ratio). The O/E mortality ratio fell progressively with age. It was highest in the 40-49 decade (4·0) and lowest in the over 80s, when the observed mortality rate was less than expected (0·9). The O/E mortality ratio was higher in men (2·3) than in women (1·7).

From this survey I conclude that angina does not have a uniformly bad prognosis, and that with the advent of beta-adrenergic blockers, the proportion considered for angiocardiography and aorto-coronary bypass grafting should be less than five per cent of all patients with angina.

     

Fatal illness in general practice

In an investigation of fatal illness during a 12-month period in a practice of 5,897 patients in Glasgow, 58 deaths (42 male, 16 female) were recorded. Malignant neoplasms and myocardial infarction in male patients of 50 years and over accounted for 27 (46·6 per per cent) of the deaths. Thirty (51·7 per cent) of the deaths took place in hospital. Fifteen (25·9 per cent) of the deaths were sudden. In patients dying in hospital of malignant, cardiac, and respiratory disease the duration of the terminal stay in hospital represented a small proportion of the total duration of the illness, the principal burden of their care falling upon their families and community resources.

In an integrated health service much yet remains to be accomplished in co-ordinating the efforts of hospital and community teams in caring for the fatally ill patient.

     

Acute myocardial infarction: an easy diagnosis in general practice?

In the imminent myocardial infarction Rotterdam (IMIR) study, contacts by patients with their general practitioners for symptoms of potential coronary artery disease were registered. Those who had acute myocardial infarction were diagnosed on the basis of the modified World Health Organization criteria, and those with this definite diagnosis were then compared with the initial diagnosis made by the general practitioner at the moment of contact without laboratory assistance.

Of the 1,343 patients included in the study, 93 (seven per cent) had `definite' acute myocardial infarction and another 37 (three per cent) had `possible' acute myocardial infarction according to the diagnostic criteria used.

At the time of contact with the general practitioner 41 (44 per cent) of the 93 patients with definite myocardial infarction were recognized as such by the general practitioner, while in another 31 (33 per cent) the general practitioner diagnosed `imminent' myocardial infarction.

Of the 1,213 patients free of acute myocardial infarction at the time, 40 (three per cent) were incorrectly diagnosed by the general practitioner as having `acute' myocardial infarction.

In the 22 patients who in fact had acute myocardial infarction but in whom the general practitioner did not make this diagnosis at the time, it was found that there was an absence of physical signs and, similarly, in patients who subsequently did not have infarction the presence of physical signs was related to a falsepositive general practitioner diagnosis of myocardial infarction.

In view of the inaccuracy of the general practitioner's provisional diagnosis of acute myocardial infarction, we believe that electrocardiogram and enzyme tests should be carried out systematically in all patients who present to general practitioners with symptoms of potential coronary artery disease. Laboratory support should be readily available and we support the idea of having a special diagnostic service.

     

Coronary atherosclerosis, coronary thrombosis and myocardial infarction in autopsy cases. 8th communication: Relationship of coronary atherosclerosis and myocardial infarction (author's transl)

The autopsy reports of the Pathological Institute Erfurt of the period from 1.1.1951 until 31.12.1969 were scored for cases of coronary atherosclerosis and myocardial infarction and analysed concerning frequency and distribution of age and sex, resp. In 89.05 per cent (2131 cases) of all myocardial infarctions a coronary sclerosis was present. Males suffered significantly more frequent from these forms of ischaemic heart disease. During the period of nineteen years a significant increase of the coronary atherosclerosis in combination with a myocardial infarction was observed. This is due to the more frequent occurrence of severe forms. The increase of the frequency of the myocardial infarctions and of the weak and moderately coronary sclerosis particularly concerns the younger age groups. Callous infarcts were more frequent than fresh and relapsing ones.     

Myocardial infarction: hospital and home management in Northern Ireland

Some 262 general practitioners in the Belfast area were asked to complete a questionnaire about their attitudes and practice regarding the management of myocardial infarction at home. Of the 211 responders, only nine per cent would sometimes consider home care for patients under 65 years of age, although 55 per cent would sometimes consider home care for those over 65 years and three per cent preferred home management for this age group. In the year preceding this study, seven per cent of these general practitioners treated only 22 myocardial infarction patients under 65 years of age at home (two per cent of all cases in the area). Home care for myocardial infarction patients appears to be less popular in Belfast than in other parts of the United Kingdom. The views of the general practitioners concerning home care are discussed.     

Sudden cardiac death: an 11-year postmortem analysis in the region of Epirus, Greece

The aim of the study was to determine the rate of sudden cardiac death in people aged between 1 and 80 years, and to investigate its etiology. All autopsies performed during an 11-year period were reviewed. Circumstances of death, individual's information, and post-mortem findings were determined. Among 1254 sudden death autopsies performed during the study period, 688 cases were recognized as sudden cardiac death (79.8% males). The estimated annual frequency of sudden cardiac death in the region of Epirus was 18.6/100,000. The major cause of death was ischemic heart disease (82%), and in 2.6%, death was unexplained. Among our study's total population, 4.1% were <35 years old. The estimated annual rate of sudden cardiac death in the population 1-35 years old was 1.78/100,000. The most common etiology in that age group was atherosclerosis (17.8%), myocarditis (10.7%), and cardiomyopathies (10.7%), whereas 39.3% exhibited structurally normal heart. Although ischemic heart disease accounts for most of sudden cardiac death episodes, many other causes contribute. Most sudden deaths in the young were "unascertained". The likely cause of death in these cases might be a primary arrhythmogenic disorder. Correct identification of such cases at autopsy will enable an appropriate clinical screening of surviving relatives.     

Pathological evaluation of coronary lesions in cases of cardiac rupture during acute myocardial infarction: An autopsy study of 148 out-of-hospital sudden death cases

We pathologically evaluated coronary artery lesions of left ventricular ruptures during acute myocardial infarctions (148 sudden out-of-hospital death cases; 93 men and 55 women; age range 42–94 years; mean age 68.9 years; 143 atherosclerotic and 5 non-atherosclerotic lesions). Among the 143 hearts with atherosclerotic coronary lesions, three-vessel disease was most frequent, and plaque rupture or erosion and occlusive thrombus were identified in most cases. Ages of the main component of the occlusive thrombus in the culprit coronary artery corresponded histopathologically to those of myocardial infarction. One of the most outstanding features in this pathological study is that acute thrombus in the culprit coronary artery was identified morphologically in most of the cases with advanced myocardial infarction (3 or more days). On the other hand, in cases of fresh myocardial infarction, a preceding mural non-occlusive organizing thrombus was observed mostly underneath the main component of the thrombus. It is suggested that, in most cases, cardiac rupture during acute myocardial infarction occurs at the time of a new ischemic event caused by a new thrombotic coronary lesion.     

Sudden death and acute myocardial infarction in a metropolitan area, 1970-1980. The Minnesota Heart Survey

To determine the causes of the nationwide decline in deaths due to coronary heart disease, the Minnesota Heart Survey enumerated coronary deaths among persons 30 to 74 years old in Minneapolis-St. Paul. The survey also ascertained rates of hospitalization and case fatality during hospitalization for acute myocardial infarction. For deaths occurring between 1970 and 1978 that were due to coronary heart disease, the rates outside the hospital declined by 43 per cent in men and 40 per cent in women, and the rates in hospital emergency rooms increased by 311 per cent in men and 200 per cent in women. In both these years about two thirds of all such deaths occurred outside hospital wards. Between 1970 and 1980, hospitalization rates for acute infarction in persons 30 to 74 years old declined 8 per cent among men and 26 per cent among women, and case fatality in the hospital in persons 45 to 74 years old declined 29 per cent in men and 27 per cent in women. These changes are probably due to the combined influence of changes in risk factors in the population and improved care of patients with acute myocardial infarction before and during hospitalization.     

The repetitive ventricular response in man. A predictor of sudden death

We examined the value of cardiac pacing for assessing ventricular electrical instability and for predicting ventricular tachycardia and sudden death in 50 patients with refractory symptomatic ventricular tachycardia, 12 normal patients, and 48 survivors of a recent myocardial infarction. The repetitive ventricular response (two or more ventricular premature beats produced by a single ventricular pacing stimulus during control of heart rate with atrial pacing) was absent in all 12 normal patients but was present in 44 of the 50 patients (88 per cent) with recurrent ventricular tachycardia (P less than 0.001). Of the 48 survivors of myocardial infarction, 19 had repetitive ventricular responses. During the next 12 months 15 of these patients (79 per cent) had symptomatic ventricular tachycardia or sudden death, or both, as compared with four of 29 patients (14 per cent) who did not have repetitive ventricular responses (P less than 0.001). The repetitive ventricular response identifies patients with life-threatening ventricular instability, but it is still an investigational technic that should be used only with due precautions.     

Long-term follow-up of asymptomatic healthy subjects with frequent and complex ventricular ectopy

From 1973 to 1983 we followed 73 asymptomatic healthy subjects who were discovered to have frequent and complex ventricular ectopy. Ventricular ectopy in these subjects was measured by 24-hour ambulatory electrocardiography, which showed a mean frequency of 566 ventricular ectopic beats per hour (range, 78 to 1994), with multiform ventricular ectopic beats in 63 per cent, ventricular couplets in 60 per cent, and ventricular tachycardia in 26 per cent. Asymptomatic healthy status was confirmed by extensive noninvasive cardiologic examination, although cardiac catheterization of a subsample of subjects disclosed serious coronary artery disease in 19 per cent. Follow-up for 3.0 to 9.5 years (mean, 6.5) was accomplished in 70 subjects (96 per cent) and documented one sudden death and one death from cancer. Calculation of a standardized mortality ratio (Monson's U.S. data, 8th revision) for 448 person-years of follow-up indicated that 7.4 deaths were expected, whereas 2 occurred (standardized mortality ratio, 27; P less than 0.05). A comparison of survival of the study cohort with that of persons without coronary artery disease or with mild disease, patients with moderate disease, and men with unrecognized myocardial infarction showed a favorable prognosis for the study cohort over 10 years. We conclude that the long-term prognosis in asymptomatic healthy subjects with frequent and complex ventricular ectopy is similar to that of the healthy U.S. population and suggests no increased risk of death.     

Aspirin, sulfinpyrazone, or both in unstable angina. Results of a Canadian multicenter trial

We performed a randomized, double-blind, placebo-controlled trial in 555 patients with unstable angina who were hospitalized in coronary care units. Patients received one of four possible treatment regimens: aspirin (325 mg four times daily), sulfinpyrazone (200 mg four times daily), both, or neither. They were entered into the trial within eight days of hospitalization and were treated and followed for up to two years (mean, 18 months). The incidence of cardiac death and nonfatal myocardial infarction, considered together, was 8.6 per cent in the groups given aspirin and 17.0 per cent in the other groups, representing a risk reduction with aspirin of 51 per cent (P = 0.008). The corresponding figures for either cardiac death alone or death from any cause were 3.0 per cent in the groups given aspirin and 11.7 per cent in the other groups, representing a risk reduction of 71 per cent (P = 0.004). Analysis by intention to treat yielded smaller risk reductions with aspirin of 30 per cent (P = 0.072), 56 per cent (P = 0.009), and 43 per cent (P = 0.035) for the outcomes of cardiac death or nonfatal acute myocardial infarction, cardiac death alone, and all deaths, respectively. There was no observed benefit of sulfinpyrazone for any outcome event, and there was no evidence of an interaction between sulfinpyrazone and aspirin. Considered together with the results of a previous clinical trial, these findings provide strong evidence for a beneficial effect of aspirin in patients with unstable angina.     

Coronary heart disease: account of a preventive clinic in general practice

Men between the ages of 25 and 45 years attending a surgery were screened for risk of heart disease. An `at-risk' group of 188 men were identified and 118 of them (63 per cent) accepted an invitation to attend a coronary heart disease prevention clinic at the practice. A sample of the attending group showed favourable changes in risk factors one year later.

Subsamples of 20 men from the attending and non-attending groups were interviewed at the clinic or at home; they showed significant differences with respect to employment status, family history of myocardial infarction and knowledge about coronary heart disease as a cause of death in the United Kingdom. Implications for preventive programmes of this nature are discussed, and the need to utilize routine doctor-patient contacts for health education and prevention is stressed.

     

Sudden death in childhood and adolescence

Sudden natural deaths of individuals between the ages of 2 and 20 years which occurred during a 20-year period were identified from mortuary records. Necropsy reports and histological sections were reviewed; 169 sudden natural deaths were identified amongst 1012 deaths in that age group. Ninety-two sudden deaths occurred to children with recognized disorders; congenital heart disease, asthma, and epilepsy were the commonest problems identified. Amongst the 77 deaths of apparently healthy children, infection was the most frequently recognized disease. Only 11 deaths were unexplained, comprising 1 per cent of the necropsy population or 6.5 per cent of sudden natural deaths, a much smaller proportion than pertains in infancy. Necropsy examination of children dying suddenly yields useful information.     

Myocardial infarction and estrogen therapy in post-menopausal women.

Data obtained from two multipurpose surveys of hospitalized patients were examined to determine the risk of nonfatal acute myocardial infarction in post-menopausal women 40 to 75 years of age in relation to use of estrogen-containing drugs. Eight (2.4 per cent) of 336 myocardial infarction patients and 330 (4.9 per cent) of 6730 reference patients were regular estrogen users (crude rate ratio, 0.47) at the time of hospitalization. After control for confounding variables -- among them, age, past history of myocardial in farction, angina, diabetes, and hypertension (alone or in combination) and cigarette smoking -- the summary point estimate of rate ratio was 0.97 with 95 per cent confidence limits of 0.48 and 1.95. Thus, there was no evidence of a statistically significant association between current regular use of estrogens and nonfatal acute myocardial infarction.     

Emergency coronary angioplasty in refractory unstable angina

We performed percutaneous transluminal coronary angioplasty as an emergency procedure in 60 patients with unstable angina pectoris that was refractory to treatment with maximally tolerated doses of beta-blockers, calcium antagonists, and intravenous nitroglycerin. The initial success rate for angioplasty was 93 per cent (56 patients). There were no deaths related to the procedure, although total occlusion occurred in four patients. Despite emergency bypass grafting, all four sustained a myocardial infarction. All the patients were followed for at least six months. Late cardiac death occurred in one patient, whereas eight had recurrent angina pectoris. There was no progression to myocardial infarction. The restenosis rate was 28 per cent (13 of 46) in the patients with initially successful coronary angioplasty who had repeat angiography. Improved cardiac functional status after sustained successful coronary angioplasty was demonstrated by an almost normal capacity on bicycle exercise testing and the absence of ischemia during thallium isotope studies in 80 per cent. We conclude that emergency percutaneous transluminal coronary angioplasty may be useful for the treatment of selected patients with unstable angina pectoris who are unresponsive to intensive pharmacologic treatment.     

The doctor's deputizing service in a single-handed practice

The out-of-hours calls received by a doctor's deputizing service on behalf of a single-handed general practitioner were studied over the course of one year.

It was found that the overall rate of call (66.3 per 1,000 patients per year) and the rate of night call (10 per 1,000 patients per year) differed little from the rates found by general practitioners who did their own out-of-hours calls. The main users of the service were children under five and women. The time when the service was used least was between 23.00 and 07.00.

It is concluded that employing a deputizing service did not necessarily increase the rate of out-of-hours calls, but that the rate was influenced by the age/sex structure of the practice list. The most economical time to employ the service was found to be from 23.00 to 07.00.

     

Prognostic value of exercise EKG testing in asymptomatic normotensive subjects. A prospective matched study

We prospectively studied 135 asymptomatic normotensive subjects with exercise-induced ST ischemic depression of 1 mm or more and compared them with 379 controls. At least two controls with negative responses on the exercise electrocardiographic (EKG) test were selected for each case and were matched for age, sex, work, community, and coronary-risk-factors index. The end points considered were the following coronary events: angina pectoris, myocardial infarction, and sudden death. After a median follow-up period of 6.0 years for the cases and 6.4 years for the controls, the relative risk was 5.55 (95 per cent confidence limits, 2.75 to 11.22). Coronary events occurred significantly earlier in the cases than in the controls. Our data also suggest that the exercise EKG response is a particularly good prognostic indicator for myocardial infarction. In addition, our analysis has confirmed the predictive roles of age, smoking, blood pressure, and the coronary-risk-factors index and suggests that the exercise EKG response is an additional independent risk indicator for coronary events.