THE EXERCISE TEST IN ELECTROCARDIOGRAPHY—Detection of Coronary Artery Disease

Master has proposed a test for detection of latent coronary artery disease by means of electrocardiograms made after standard exercises consisting of walking back and forth over two steps. This test was used in routine examinations of airline employees, with the special purpose of evaluating the test for use on apparently normal persons.Of 526 males tested, 283 were under 40 years of age and 243 were aged 40 years or more. Coronary artery disease was indicated in 16 males in whom there was no other evidence of the disease, five of whom had hypertension. No electrocardiographic evidence of coronary artery disease was obtained for three males in whom the disease was diagnosed or was strongly suspected. The test gave nagative results for 16 males whose electrocardiograms made at rest were compatible with coronary artery disease. The percentage of positive results in men under 40 years of age was 4.3; in men over 40, 0.6.Of a control group of 60 women under the age of 35 years, in none of whom coronary artery disease was detected by other means, six had positive response to the test.It is concluded that Master''s criterion for the most common positive finding, a depression in the ST segment of over 0.5 mm., allows too many false positive findings and that a figure of 1.0 mm. to 1.5. mm. would be a better index. A negative finding apparently does not exclude the possibility of coronary artery disease or of coronary occlusion. The usual 12-lead electrocardiogram made at rest appeared to be of greater value in detection of latent coronary artery disease in apparently normal persons.     

Prevalence of asymptomatic myocardial ischaemia in diabetic subjects.

OBJECTIVE--To compare the prevalence of silent myocardial ischaemia associated with coronary artery disease in diabetic subjects with that in controls of similar age and sex. DESIGN--A controlled study in which subjects with positive findings on exercise electrocardiography, 24 hour electrocardiographic recording, or dynamic thallium scintigraphy (diabetics only) underwent coronary angiography. SETTING--Academic medical centre; referral based cardiology clinic. SUBJECTS--136 Diabetic subjects, of whom 72 (33 women, 39 men (mean age 46.0] were insulin dependent and 64 (19 women, 45 men (mean age 49.3] non-insulin dependent. 80 Controls matched for age and sex; all were clients of the Occupational Health Service of Oulu University Central Hospital or the State Occupational Health Service Station in Oulu in whom diabetes had been excluded by a glucose tolerance test. INTERVENTIONS--Any subject showing signs of myocardial ischaemia was referred for cardiac catheterization. MAIN OUTCOME MEASURES--Exercise electrocardiography and 24 hour electrocardiographic recording were regarded as positive if there were ST depressions of greater than or equal to 1 mm that were planar or downsloping and persisted for 0.08 seconds after the J point. Thallium tomographic imaging. With cardiac catheterisation, coronary artery lesions were classified as significant in half or more of the vessel lumen was narrowed, or insignificant if such narrowing was less than half. RESULTS--40 (29%) diabetes and four (5%) controls had positive results in one or more of the non-invasive tests. Coronary angiography was performed on 34 of the diabetics (six refused); 12 had significant coronary artery narrowing; seven had unimportant atherosclerosis; 15 had patent coronary arteries. Among the controls only one had unimportant atherosclerosis; the other three had patent arteries. CONCLUSIONS--These results confirm the high prevalence of asymptomatic myocardial ischaemia in diabetics. Non-invasive screening of diabetic subjects, however, does not seem justified because of the low preset probability of the presence of the disease and the inaccuracy of the available test methods.     

The University of Manitoba Follow-up Study: A Prospective Investigation of Cardiovascular Disease: Part I. General Description—Mortality and Incidence of Coronary Heart Disease

A prospective study of cardiovascular disease was initiated in 1946 whereby 3983 healthy North American males, 91% under age 40, were subjected to periodic electrocardiograms and medical examinations between 1948 and 1963. The health of all but five of the 3773 survivors was known in 1963. There were 210 deaths: aircraft accidents accounted for 45%, cardiovascular disease 20%, cancer 11% and other causes 23%. The aggregate mortality closely resembled that of the Canadian Life Table 1955-57 (Male). Extra deaths were observed under age 40 owing to a high frequency of flying accidents. At older ages the mortality was lower than expected because congenital and chronic diseases were excluded at entry. One hundred and forty-three developed coronary heart disease. The case fatality rate was 31%. The incidence rate for coronary heart disease rose progressively from 0.277 per thousand per year for ages 25-34 to 26.5 at ages 60-69.     

Bronchogenic carcinoma in San Diego County; relation of mortality rates to findings in mass chest x-ray survey

Nearly half the population of San Diego County was examined by chest x-ray for bronchogenic carcinoma. The disease was correctly diagnosed in 20 persons, of whom 17 died. Twenty-four others in whom it was not detected in survey films died of the disease in the following two years. Of the 20 cases found, 16 were in men, all more than 54 years of age, and of the 24 who died after "negative" classification, 20 were men over 40. The death rate for men over 40 years of age from bronchogenic carcinoma is about one in a thousand. Because of the frequently rapid progress of the disease after onset, and the poor prognosis after the appearance of symptoms, x-ray examination every six months for men over 40 should be considered.     

BRONCHOGENIC CARCINOMA IN SAN DIEGO COUNTY—Relation of Mortality Rates to Findings in Mass Chest X-Ray Survey

Nearly half the population of San Diego County was examined by chest x-ray for bronchogenic carcinoma. The disease was correctly diagnosed in 20 persons, of whom 17 died. Twenty-four others in whom it was not detected in survey films died of the disease in the following two years.Of the 20 cases found, 16 were in men, all more than 54 years of age, and of the 24 who died after “negative” classification, 20 were men over 40.The death rate for men over 40 years of age from bronchogenic carcinoma is about one in a thousand. Because of the frequently rapid progress of the disease after onset, and the poor prognosis after the appearance of symptoms, x-ray examination every six months for men over 40 should be considered.     

Diagnostic value of maximal treadmill exercise electrocardiogram in predicting coronary artery disease for asymptomatic Chinese male subjects

The value of maximal treadmill exercise electrocardiogram (TEE) in predicting coronary artery disease was evaluated in a consecutive series of 168 asymptomatic Chinese males, aged 41 to 57 years (mean 53) during annual physical examinations. Their resting electrocardiograms (ECGs) showed no abnormal Q-waves. The end-point of TEE achieved the age-predicted maximal heart rate, and no subjects had classic angina pectoris during or after TEE. Thirty-five subjects had positive electrocardiographic changes defined as reversible horizontal or downsloping ST-segment depression greater than or equal to 1.0 mv which lasted greater than or equal to 0.08 sec. Exercise thallium-201 (T1-201) myocardial imaging was performed on all 35 subjects with positive TEE; 30 subjects (86%) demonstrated normal and 5 abnormal scintigrams. Sixteen of the 30 cases with normal T1-201 scans underwent coronary arteriography, of which 14 showed normal arteriograms and two showed a less than 49% stenosis of the luminal diameter in one major artery. Of the 5 cases with abnormal scintigrams, 4 were found to have greater than 50% stenoses in at least one major artery, and only one case had a less than 49% stenosis of the right coronary artery. We concluded that TEE alone for asymptomatic individuals provided limited value in diagnosing significant coronary artery disease, especially in areas of low prevalence.     

Myocardial perfusion imaging with thallium-201: correlation with coronary arteriography and electrocardiography

Myocardial perfusion imaging with thallium-201 and electrocardiography with the subject at rest and undergoing submaximal treadmill exercise were performed in 19 men and 3 women. Selective coronary arteriography and left ventriculography showed that 7 had normal coronary arteries and 15 had coronary artery disease.The 11 persons with electrocardiographic evidence of an old myocardial infarct (q waves) had a perfusion defect at rest in the area of the infarct and a segmental abnormality of wall motion apparent on the left ventriculogram corresponding to the perfusion defect.Myocardial perfusion imaging and electrocardiography were equally sensitive in detecting coronary artery disease in exercising individuals: perfusion defects were noted in 7 of the 15 persons with coronary artery disease, and diagnostic ST-segment depression was present in 8 of the 15. Combination of the results of the two tests with exercise permitted the identification of 11 of the 15 persons and improved the sensitivity. Combination of the results of rest and exercise imaging and electrocardiography permitted the identification of 94% of the patients with coronary artery disease.Myocardial perfusion imaging with ²⁰¹TI in the subject at rest is a sensitive indicator of previous myocardial infarction. Imaging after the subject has exercised is a useful adjunct to conventional exercise electrocardiography, especially in those whose exercise electrocardiogram is non-interpretable.     

The importance of indicators of the initial phase of atherosclerosis in patients with microvascular angina

Endothelial dysfunction (ED) is generally considered to be the initial step in the progression to atherosclerosis but there is still much uncertainty about the role of the microvascular form of angina in patients with a normal coronary angiogram with regard to ED. The authors investigated the extent of endothelial perturbation and thereby whether the microvascular form of angina precedens macroscopic atherosclerosis by means of non-invasive ultrasound measurement of the intima-media thickening (IMT) in common carotid artery and flow mediated dilatation (FMD) in the brachial artery. 28 patients with stable angina with positive exercise test and ST segment depression (22 females, 6 males, average age 54 years) were compared with a control group consisting of 28 patients with no clinical signs of coronary artery disease (18 females, 10 males, average age 53 years). No significant difference in FMD% (7.3 vs. 10.8, p = 0.07) was found between the groups, though specific measurements (average dilatation of the brachial artery induced by ischemic insult, peak blood flow and peak hyperemic flow) differed considerably. Also IMT did not vary significantly between the groups (0.74 vs. 0.65, p = 0.08). In patients with IMT > 0.8 mm (6 patients in each group) a significant decrease of FMD was found as compared with patients with normal IMT (p < 0.05). It was concluded that in patients with increased IMT an inverse relationship between FMD and IMT exists both in patients with microvascular angina and in the healthy control subjects whereas in the group of patients with normal IMT no ED was demonstrated. This supports the hypothesis that the microvascular form of angina is the early stage of coronary artery atherosclerosis and this escapes angiographic recognition.     

Delayed diagnosis of symptomatic coronary artery disease in young men

Delay in making the diagnosis of symptomatic coronary artery disease was determined by studying the medical histories of 265 men aged 24.7 to 49.9 (mean 40.1) years with angiographically proven obstructive coronary atherosclerosis. The diagnosis of angina pectoris was delayed three times as often as the diagnosis of myocardial infarction, and for five times as long. The diagnosis of symptomatic coronary artery disease was delayed three and a half times more often in patients less than 35 years of age, than in patients over 45; the average time from presentation with symptoms to diagnosis was 30 times longer in patients under 35 years of age than in patients over 45.     

Reciprocal change in ST segment in acute myocardial infarction: correlation with findings on exercise electrocardiography and coronary angiography.

The clinical relevance of reciprocal changes in the ST segment occurring at the time of acute myocardial infarction was studied prospectively in 85 consecutive uncomplicated cases. Reciprocal depression of the ST segment was defined as depression of 1 mm or more in electrocardiogram leads other than those reflecting the infarct. All patients underwent maximal, symptom limited treadmill stress testing two weeks after the infarct and coronary angiography six weeks after infarction. Forty six patients had inferior, 34 anterior, and five true posterior infarction. Of the 51 patients with reciprocal changes, 45 (88%) developed exercise induced ST segment depression in areas remote from the infarction zone. At angiography all 45 patients were shown to have stenoses greater than 70% in at least two major vessels. Four patients had negative exercise electrocardiograms and were sequently shown to have single vessel disease subtending their infarct, and the remaining two patients had a false negative treadmill test result. Of the 27 patients without reciprocal changes, 21 (78%) had negative treadmill stress test results associated with single vessel coronary disease. Five had positive stress test results and multivessel coronary disease, and one had a false negative stress test result. The remaining seven patients had ST segment elevation without Q wave formation in the reciprocal areas and were assessed separately. Of these, six had positive stress test results and multivessel coronary disease and one had a negative stress test result and single vessel coronary disease to the infarct area. Twenty one patients with anterior infarcts (62%) and 27 with inferior infarcts (59%) had reciprocal changes. No differences emerged in the relation between infarct site, reciprocal change, and presence of additional coronary disease. At follow up of the 51 patients with reciprocal changes in the ST segment 36 had become symptomatic, of whom 29 had undergone coronary artery bypass surgery. By contrast, only four of the 27 patients without reciprocal changes in the ST segment had developed symptoms, and two of these had undergone coronary revascularisation. Reciprocal ST segment depression at the time of acute myocardial infarction may identify patients with severe coronary disease who are at risk of subsequent cardiac events and appears to be as reliable as results of early postinfarction treadmill stress testing in predicting the underlying coronary anatomy. When the electrocardiogram does not show reciprocal changes treadmill testing provides valuable additional information.     

Predictive value of the ear-crease sign in coronary artery disease.

The value of the ear-crease sign in predicting the presence of coronary artery disease was studied in 340 consecutive patients who underwent coronary arteriography. In this selected population, 75.6% of whom had coronary artery disease, the sensitivity of the sign was 59.5%, the specificity 81.9% and the positive predictive value 91.1%. The sign was associated with increasing age but was also independently associated with obstructive coronary artery disease. No significant correlation was found between the sign and the presence of risk factors or other signs of such disease, except for corneal arcus. In symptomatic patients the sign suggested the presence of more extensive coronary artery disease. In an asymptomatic population with a low prevalence of coronary artery disease it appears to be of limited value in predicting obstructive coronary artery disease. However, it may identify a subset of patients prone to early ageing and to the early development of coronary artery disease, whose prognosis might be improved by early preventive measures.     

Myocardial infarction,hyperthyroidism and normal coronary arteries: report of two cases.

Myocardial infarction is uncommon in persons with hyperthyroidism and also uncommon in the absence of demonstrable coronary artery disease. Cardiac catheterization and selective coronary angiography were performed in two men following apparent myocardial infarctions. Both patients were 33 years of age, thyrotoxic and angiographically free of coronary artery abnormalities.     

Cold pressor test in diagnosis of coronary artery disease: echophonocardiographic method.

The cold pressor test was used to induce myocardial ischaemia in patients with coronary artery disease and the rise in left ventricular filling pressure used as the index of myocardial ischaemia. Left ventricular filling pressure was derived from a non-invasive echophonocardiographic method. A study group of 19 consecutive patients with chest pain underwent the cold pressor test before coronary angiography. Eighteen responded with a rise in filling pressure exceeding 30% and, of these, 17 had serious coronary artery disease (three single vessel, one two vessel, and 13 triple vessel disease; one had coronary artery spasm only). The remaining patient, who showed no rise in filling pressure, did not have coronary artery disease. None of 15 normal controls showed a rise greater than 5% (patients with coronary artery disease versus normal controls p less than 0.001). The cold pressor test would be suitable for patients who cannot or should not exercise and may be combined with exercise electrocardiograms to improve the information content, as it uses a different marker of myocardial ischaemia.     

Seroepidemiological survey of human toxoplasmosis in Osorno, Region X, Chile, 1998]

A serological survey was carried out in Osorno X Region, Chile (40 degrees 21'-40 degrees 46' South lat, and 73 degrees 26' -72 degrees-46' West long.). An indirect hemagglutination test (IHAT) for toxoplasmosis was performed to 305 persons--160 blood donors and 145 with sexually transmitted disease (STD). The age of the surveyed persons (167 males and 138 females) varied between 10 and 72 years. IHAT titers > 16 were considered as positive. The general prevalence was 20.3%--21.2% in blood donors and 19.3% in persons with some STD--with no differences between males and females. However, significant differences between males and females with STD were found (35.6% and 8.1% respectively). No differences between urban and rural inhabitants were found with a slight higher prevalence in the urban ones. No antibodies against Toxoplasma gondii were detected in six AIDS patients. The importance of performing toxoplasmosis immunodiagnosis and individual prophylaxis to avoid the infection in high risk group are recommended.     

Circadian variation and age dependence of human atrial natriuretic peptide levels in hospitalized patients

Circadian variation of plasma levels of human atrial natriuretic peptide (hANP) was studied in 8 patients less than or equal to 65 a of age (mean +/- SD = 43.8 +/- 13 a; 5 females, 3 males) and in 15 patients greater than 65 years of age (mean +/- SD = 81.4 +/- 5.7 a; 9 females, 6 males). Intraindividual variation was up to 40% relative to the day's mean level in both groups. A significant elevation of hormone levels in the evening was observed in patients greater than 65 years of age (P less than 0.002), no circadian rhythm could be detected in patients less than or equal to 65 years of age. All patients except the two eldest had average plasma levels of hANP within our normal range of 3-75 ng/l (N = 106; mean +/- SD = 29.9 +/- 15.3), found in healthy persons up to 65 years of age. We propose, that in the elderly hANP levels rise during the day by edema because of latent renal and/or cardial insufficiency. At rest, in the evening and during the night edema is eliminated by the well known nycturia, which might well be facilitated or at least partially caused by elevated levels of hANP.     

Sudden death due to recreational exercise in physicians

In a period from 1982-2002 we noticed five dead among Croatian male physicians aged 34 to 67, during or after recreational physical exercise: swimming, soccer, tennis and jogging. Three of them who were autopsied, have been non-smokers and without previous symptoms. In all coronary heart disease was found. The left descending anterior artery was stenotic in one and occluded in two, with myocardial scars in one. An acute myocardial infarction was found in none of them, and in two-left ventricular hypertrophy 15 and 18 mm. We could not find a recent medical record in those physicians including a clinical finding and other findings. Two physicians who were not been autopsied, had possible an alcohol cardiomyopathy. Both of them were smokers. In Croatia about 7% of the whole population are engaged in recreational physical exercise. In a period of twenty years (1982-2002) we noticed 43 sudden and unexpected deaths during or immediately after physical exercise: it reached 43/6,300,000 sudden death in Croatia in twenty years or 2.15/315,000 yearly among persons engaged in physical exercise. In Croatia there are 4,957 male physicians-specialists, and a rate of sudden cardiac death during or immediately after physical exercise in this group reached 5/99,140 in 20 years or 1/19,828 every four years. A medical check up before recreational physical exercise is essential including a clinical examination, a serum concentration of risk factors and other risk factors, an electrocardiogram at rest, a stress test and echocardiography in clinical indication, as are medical controls over persons taking exercise. This study shows that medical evaluation is important because of the underlying problems such as sudden death during exercise. In non-trained persons and in the elderly a physical exercise should be recommended of a gradually intensity, which could not exceed 6 METs.     

The concentrations of methaemoglogin, carboxyhaemoglobin and somehaematological parameters in tobacco snuff addicts in Igbo of Nigeria.

Methaemoglobin, carboxyhaemoglobin concentrations and some haematological parameters were studied in fifty tobacco snuff addicts (40 males and 10 females) in some villages of Anambra State, Nigeria. The aim was to investigate possible adverse effects of tobacco snuff in addicts in Igbos of Anambra State. Fifty apparently healthy persons (25 males and 25 females) who do not inhale snuff were used as controls. The age range of tests and control subjects was 25-65 years. The results showed no statistically significant difference when the tests group was compared with the control group. A comparison of the results on the basis of sex, age and period of exposure, showed no significant differences. Blood picture in test and control groups was normocytic and normochromic. The results suggest that tobacco snuff may not have any adverse effect on haemoglobin metabolism and erythropoiesis.     

青海土族体质人类学研究

1995年7—8月对青海土族251人(男131、女120)进行了53项活体测量和13项活体观察,结果表明,青海土族的体质特征是：男性眼裂开度中等者较多、女性宽者过半。蒙古褶出现率男性过半,女性占40.8%。94%有上眼睑皱褶。鼻型属中鼻型,头型属中头型。面型,男性以过狭面、狭面和中面型为主,女性以狭面和中面型为主。男身高为1634mm,女为1543mm。通过与西北及其它少数民族比较发现：青海土族与东乡族、保安族、羌族体质相近。     

Dobutamine stress magnetic resonance imaging suffices for the demonstration of myocardial ischaemia and viability

We report three patients in whom dobutamine stress magnetic imaging (DS-MRI) was essential in assessing myocardial ischaemia. Two patients were referred to the cardiologist because of chest pain. Patient A had typical exertional angina and a normal resting electrocardiogram (ECG). Patient B had typical exercise-induced angina and had recently experienced an attack of severe chest pain at rest for 15 minutes. The ECG showed a complete left bundle branch block (LBBB). Patient C was referred for heart failure of unknown origin. There were no symptoms of chest pain during rest or exercise. Echocardiography in this patient demonstrated global left ventricular (LV) dilatation, systolic dysfunction and a small dyskinetic segment in the inferior wall. In all these patients exercise stress testing had failed to demonstrate myocardial ischaemia. Patients A and C produced normal findings whereas in patient B the abnormal repolarisation due to pre-existent LBBB precluded a diagnosis of ischaemia.Breath-hold DS-MRI was performed to study LV wall motion and wall thickening at rest through increasing doses of dobutamine. A test was considered positive for myocardial ischaemia if wall motion abnormalities developed at high-dose levels of the drug (20 μg/kg/min or more with a maximum of 40 μg/kg/min) in previously normal vascular territories or worsened in a segment that was normal at baseline. Recovery of wall thickening in a previously hypokinetic or akinetic segment at a low dose of dobutamine (5-10 μg/kg/min) was taken as proof of viability.Patients A and B developed hypokinesia progressing into akinesia at high-dose dobutamine in the anteroseptal area of the LV indicative of ischaemia. These findings were corroborated by coronary angiography demonstrating severe coronary artery disease which led to coronary artery bypass grafting (CABG) in patient A and balloon angioplasty in patient B. In patient C global recovery of LV contractions during low-dose dobutamine was followed by hypokinesia in the inferoseptal area during high-dose dobutamine. This biphasic response indicates myocardial viability as well as ischaemia. CABG was carried out because of multiple stenoses in the left coronary artery. Post-operatively LV function normalised.DS-MRI is a valuable method for detecting myocardial ischaemia and viability in patients with suspected coronary artery, and can be applied in every hospital with MRI equipment at its disposal.