The bearing of race, sex, age, and nutritional state on the precordial electrocardiograms of young South African Bantu and Caucasian subjects

Prevalence of major and minor electrocardiographic abnormalities and their relationship with cardiovascular risk factors in Angolans

Aims

To identify the prevalence of major and minor electrocardiographic abnormalities and their association with the main risk factors for cardiovascular disease in a population in the province of Bengo, northern Angola.

Methods

A cross-sectional community-based study was conducted and a representative random sample stratified by sex and age was selected. In total, 2379 black individuals were included in the final analysis. A standard 12-lead ECG were recorded from all participants, analyzed and processed by the University of Glasgow software and coding by the Minnesota code.

Results

22.3% of participants had minor electrocardiographic abnormalities and 4.58% major ECG abnormalities. The most common minor ECG abnormalities were abnormal T wave inversion, minor isolated ST abnormalities and premature beats. The most common major ECG abnormalities were Left ventricular hypertrophy with major ST-T abnormalities, Ventricular conduction defects and major Q-wave abnormalities. Hypertension, diabetes mellitus, hypercholesterolemia, alcohol consumption and smoking, were significantly associated with major and minor electrocardiographic abnormalities.

Conclusions

In this study several participants had minor and major electrocardiographic abnormalities. Minor electrocardiographic abnormalities were more prevalent in men and major abnormalities in women. The electrocardiographic abnormalities had significant associations with the main cardiovascular risk factors.

Reference values of ECG parameters derived from 906 echocardiographically confirmed healthy Indian children: A population-based study from Gujarat

INTRODUCTION

There are few published studies on reference ranges of ECG parameters in children; some ethnic differences have been described.

METHODS

We studied digital 12‑lead ECGs (1000 samples/s) from 906 healthy rural Indian children (467 boys: 439 girls) aged 5-15 years. PR, QRS, and QT were measured using superimposed median beat. Age-wise normal limits (median, 2nd and 98th percentile) were defined.

RESULTS

Heart rate decreased while PR interval and QRS duration increased with age. QTcB interval remained unchanged from 5 to 12 years and decreased thereafter due to QTcB shortening in boys but not in girls. "Juvenile T wave pattern" was seen in 95% of children aged 5-8 years in lead V1 and 55-60% in V2, V3; it decreased with age. RV dominance (R/S > 1) in lead V1 was seen in 13% at 5 years, 1% at 10 years and none at 14 years.

CONCLUSION

Reference ranges in Indian children are similar to those in other ethnic groups.

Epidemiology of ischaemic heart disease in sub-Saharan Africa

BACKGROUND

The epidemiology of ischaemic heart disease (IHD) in sub-Saharan Africa (SSA) remains largely enigmatic. Major obstacles to our understanding of the condition include lack of reliable health statistics, particularly cause-specific mortality data, inadequate diagnostic capabilities, shortage of physicians and cardiologists, and misguided opinions.

METHODS

This review of the epidemiology of ischaemic heart disease in sub-Saharan Africa involved a systematic bibliographic MEDLINE search of published data on IHD in SSA over the past century. Search words included epidemiology, ischaemic (coronary) heart disease, myocardial infarction, cardiovascular risk factors and sub-Saharan Africa. Selected data are presented on the prevalence of cardiovascular risk factors and mortality from ischaemic heart disease from different countries representing the main regions of the continent.

RESULTS

Although IHD in SSA remains relatively uncommon, its prevalence is predicted to rise in the next two decades due to the rising prevalence of risk factors, especially hypertension, diabetes, overweight and obesity, physical inactivity, increased tobacco use and dyslipidaemia. It is estimated that age-standardised mortality rates for IHD will rise by 27% in African men and 25% in women by 2015, and by 70 and 74%, respectively by 2030.

CONCLUSION

Ischaemic heart disease remains relatively uncommon in SSA, despite an increasing prevalence of risk factors, but its incidence is rising. The pace and direction of economic development, rates of urbanisation, and changes in life expectancy resulting from the impact of pre-transitional diseases and violence will be major determinants of the IHD epidemic in SSA. The best window of opportunity for prevention of the emerging epidemic of ischaemic heart disease in sub-Saharan Africa is now.

Redefining the ECG in urban South Africans: electrocardiographic findings in heart disease-free Africans

BACKGROUND

The 12-lead electrocardiogram (ECG) represents an important diagnostic tool for detecting heart disease, but the "normal" ECG in those of African descent has yet to be definitively described.

METHODS

We systematically analysed 12-lead ECGs from 387 urban South Africans determined to be heart disease free (using the Minnesota code) following advanced cardiologic assessment, including echocardiography, at the Baragwanath Hospital in Soweto, South Africa.

RESULTS

123 males (32%, 41.2 ± 14.5 years) and 264 females (37.4 ± 14.2 years) were studied. Most were in sinus rhythm (87%) and had normal axis (89%). Mean interval data were: PR interval (156 ± 28 ms; 95% CI: 153-159 ms), QRS duration (82 ± 16 ms; 95% CI: 80-84 ms), QT interval (379 ± 48 ms; 95% CI: 374-384 ms) and QTc interval (426 ± 32 ms; 95% CI: 423-429 ms). Overall, 199 (51%; 95% CI: 46.0% to 56.0%) subjects had an ECG "abnormality" or normal variant and 67 ECGs (17%; 95% CI: 13.3% to 20.7%) had major and minor abnormalities. ECG changes normally ascribed to myocardial ischaemia were: i) ST elevation (9.3%; 95% CI: 6.2 to 11.9%), ii) Q waves (7.4%; 95% CI: 4.4 to 9.5%) and iii) ST depression (2.3%; 95% CI: 0.8 to 3.8%). Sokolow-Lyon Index voltage exceeding 38 mm indicative of left ventricular hypertrophy was more prominent in males than females (23.6% vs. 6.4%; OR=4.5; 95% CI: 2.3-8.5).

CONCLUSIONS

These data provide a contemporary reference to the 12-lead ECG in urban South Africans found to be heart disease free, with both major and minor abnormalities detected.

Ethnic differences in physiological cardiac adaptation to intense physical exercise in highly trained female athletes

BACKGROUND

Ethnicity is an important determinant of cardiovascular adaptation in athletes. Studies in black male athletes reveal a higher prevalence of electric repolarization and left ventricular hypertrophy than observed in white males; these frequently overlap with those observed in cardiomyopathy and have important implications in the preparticipation cardiac screening era. There are no reports on cardiac adaptation in highly trained black females, who comprise an increasing population of elite competitors.

METHODS AND RESULTS

Between 2004 and 2009, 240 nationally ranked black female athletes (mean age 21+/-4.6 years old) underwent 12-lead ECG and 2-dimensional echocardiography. The results were compared with 200 white female athletes of similar age and size participating in similar sports. Black athletes demonstrated greater left ventricular wall thickness (9.2+/-1.2 versus 8.6+/-1.2 mm, P<0.001) and left ventricular mass (187.2+/-42 versus 172.3+/-42 g, P=0.008) than white athletes. Eight black athletes (3%) exhibited a left ventricular wall thickness >11 mm (12 to 13 mm) compared with none of the white athletes. All athletes revealed normal indices of systolic and diastolic function. Black athletes exhibited a higher prevalence of T-wave inversions (14% versus 2%, P<0.001) and ST-segment elevation (11% versus 1%, P<0.001) than white athletes. Deep T-wave inversions (-0.2 mV) were observed only in black athletes and were confined to the anterior leads (V(1) through V(3)).

CONCLUSIONS

Systematic physical exercise in black female athletes is associated with greater left ventricular hypertrophy and higher prevalence of repolarization changes than in white female athletes of similar age and size participating in identical sporting disciplines. However, a maximal left ventricular wall thickness >13 mm or deep T-wave inversions in the inferior and lateral leads are rare and warrant further investigation.

Comparison of electrocardiographic findings and associated risk factors between Taiwan Chinese and US White adults

BACKGROUND

Electrocardiographic (ECG) findings are known to differ by race, however, systematic comparisons of findings between eastern and western countries are rare.

OBJECTIVE

To compare the ECG findings and associated coronary heart disease (CHD) risk factors between Taiwan Chinese and US White adults aged >or=40 years.

METHODS

We compared the prevalence rate of Minnesota Code criteria based ECG findings and associated CHD risk factors by using data from the third National Health and Nutrition Examination Survey (NHANES III) and the Nutrition and Health Survey in Taiwan (NAHSIT, 1993-1996).

RESULTS

Examining all the ECG findings collectively, we observed a higher prevalence of major Minnesota Code findings in Taiwan Chinese women than in US White women (15.0% vs. 10.5%), particularly ST segment depression (5.4% vs. 2.4%) and T wave abnormalities (10.8% vs. 4.8%). The prevalence of major Minnesota Code findings was similar in both Taiwan Chinese and US White men (22.7% vs. 19.6%). Taiwan Chinese men had a higher prevalence of ST segment elevation (13.7% vs. 0.9%). Taiwan Chinese also had a higher prevalence of left ventricular hypertrophy with repolarization change than US Whites in both sexes (2.7% vs. 1.4% for men, 4.3% vs. 1.3% for women). Taiwan Chinese had more favorable CHD risk factor profiles than US Whites, including lipid profile, obesity, central obesity, and smoking status. The prevalence of hypertension was similar between the two groups, however, a lower percentage of Taiwan Chinese received treatment. Taiwan Chinese men had a lower prevalence of diabetes mellitus than US White men, whereas Taiwan Chinese women had a higher prevalence than US White women.

CONCLUSION

These results suggest that substantial differences in ECG findings exist between Taiwan Chinese and US Whites which cannot be entirely explained by CHD risk factors alone.

Ethnic differences in electrocardiographic amplitude measurements

BACKGROUND

There is controversy regarding ethnic differences in electrocardiographic (ECG) patterns because of potentially confounding socioeconomic, nutritional, environmental and occupational factors.

METHODS

We reviewed the first 1000 medical files of a multi-ethnic community, where all individuals shared similar living conditions. Only healthy adults age 15 to 60 years were included. Wave amplitudes were measured manually from the standard 12 lead ECG. Minnesota coding was used.

RESULTS

ECGs from 597 subjects were included in the study: 350 Saudi Arabians, 95 Indians, 39 Jordanians, 17 Sri-Lankans, 39 Filipinos, and 57 Caucasians; 349 were men. The mean+/-SD of Sokolow-Lyon voltage (SLV) in men was significantly different among ethnic groups (2.9+/-0.86, 2.64+/-0.79, 2.73+/-0.72, 3.23+/-0.61, 2.94+/-0.6, 2.58+/-0.79 mV; P=0.0006, for Saudis, Indians, Jordanians, Filipinos, Sri-Lankans, and Caucasians, respectively). SLV was similar among ethnic groups in women. The prevalence of early transition patterns was also different among ethnic groups in men but not women (15.8%, 34.6%, 17.9%, 21.7%, 35.3%, 26.8% in Saudi, Indian, Jordanian, Filipino, Sri-Lankan, and Caucasian men, respectively, P=0.037). T wave amplitude was significantly different among ethnic groups in selected leads.

CONCLUSIONS

ECG wave amplitude differs with ethnic origin even when other factors are similar. Using SLV of 3.5 mV as a criterion may overestimate the incidence of left ventricular hypertrophy in some ethnic groups. The pattern of high R wave in lead V1 is common in healthy adults in certain ethnic groups. T wave height differs with ethnic origin and sex.

The early repolarization normal variant electrocardiogram: correlates and consequences

PURPOSE

We compared the characteristics and outcomes of patients with "early repolarization" electrocardiograms (ECGs) with those who had normal ECGs.

METHODS

In 1983 to 1985, we collected photocopies of 2234 selected ECGs from 73088 patients undergoing health examinations. Excluding 153 ECGs with missing data or that were judged to be abnormal, the remaining ECGs were reinterpreted in 2000 by cardiologists as showing early repolarization (n = 670), or being borderline (n = 330) or normal (n = 1081). Characteristics and outcomes of persons with early repolarization ECGs were compared with those who had normal ECGs using analysis of variance, logistic regression, or proportional hazards models. Information on exercise was available in 325 patients.

RESULTS

Patients with early repolarization were more likely to be male (81% [n = 583] vs. 33% [n = 360]), <40 years old (60% [n = 441] vs. 37% [n = 403]), black (48% [n = 384] vs. 26% [n = 280]), and more athletically active (mean [+/- SD], 10.4 +/- 1.3 hours per week of activity vs. 6.4 +/- 1.2 hours per week of activity) than those with normal ECGs. Patients with early repolarization were not more likely to be hospitalized (hazard ratio [HR] = 1.0; 95% confidence interval [CI]: 0.9 to 1.2) or to die (HR = 0.8; 95% CI: 0.6 to 1.2) during follow-up than those with normal ECGs. Outpatient diagnoses were not more common in those with early repolarization; arrhythmias were actually less common (P <0.01).

CONCLUSION

Although especially prevalent in young, athletic, black men, early repolarization is not rare in other patients. The long-term prognosis of early repolarization is benign.

Ethnic differences in the ST segment of the electrocardiogram: a comparative study among six ethnic groups

Deviation of the ST segment of the electrocardiogram (ECG) may signify infarction or ischemia. Prior studies suggest that normal ECG patterns may differ among ethnic groups. We retrospectively reviewed the first thousand medical files of a multiethnic community, where all individuals shared similar living conditions. Only healthy adults, aged 15 to 60 years, were included. Along with age, the most common causes for exclusion were diabetes, hypertension, and ischemic heart disease. A total of 597 subjects (349 men) were included: 350 Saudi Arabians, 39 Filipinos, 95 Indians, 17 Sri-Lankans, and 57 Caucasians. Twenty men and one woman had an ECG pattern of early repolarization (ST segment elevation with upward concavity, notching on QRS, and large symmetrical T wave), with no difference in incidence among ethnic groups. ST segment elevation (2 mm in any of the leads V1-V4, or 1 mm in any of the other leads) without criteria of early repolarization occurred in 11.58%, 13.46%, 3.57%, 4.35%, 11.76%, 7.32% of Saudi, Indian, Jordanian, Filipino, Sri-Lankan, and Caucasian men, respectively (P =.61). Only one Jordanian and 2 Indian women had this pattern. However, Filipino men had higher median ST segment levels than others in leads V1 and V3. Among women, the median ST segment level was iso-electric in all leads in all ethnic groups. Only 3 subjects had ST segment depression >1 mm. Significant ST segment elevation is common in normal healthy men but may not fulfill criteria for early repolarization; it has no ethnic predilection. ST segment elevation is uncommon in normal women. ST segment depression is a rare finding in healthy adults regardless of ethnic origin.

Ischemic heart disease in black South African stroke patients

BACKGROUND AND PURPOSE

Stroke patients in western countries frequently have coronary artery disease (CAD). In black Africans, CAD has been reported as being rare in both stroke patients and the general population. In this study, an attempt has been made to determine the prevalence of CAD in a black South African stroke population.

METHODS

The prevalence of CAD was determined by indicators identified through a series of 5 observational studies in black patients diagnosed with stroke. CAD indicators included (1) bedside diagnosis in 741 patients; (2) resting ECG in 555 consecutively admitted patients; (3) a combination of clinical examination, cardiac ultrasound, radionuclide scintigraphy, and multigated blood pool studies in 102 consecutively admitted patients; (4) thallium scintigraphy in 60 patients; and (5) necropsy in 23 patients.

RESULTS

On bedside questioning, only 0.7% complained of previous angina. There was no history given of myocardial infarction (MI), but documentation of this was found in the clinical notes of 0.7% of the patients. In the resting ECG study, evidence of myocardial ischemia was present in 14.6% and MI in 2.1%. In the combined study, cardiac ischemia was documented on ECG in 12.7% of patients and evidence of previous MI in 5.8%. Cardiac scintigraphic studies revealed changes of myocardial ischemia in 31.7% and MI in 13.3% of the 60 patients studied. Four (17.4%) of 23 patients in the necropsy study had histological evidence of previous MI, and 50% of all patients had evidence of >50% atherosclerotic stenosis in 1, 2, or 3 coronary arteries.

CONCLUSIONS

The prevalence of CAD in black African stroke patients is significantly higher than has been documented in the general nonstroke black population as well as in stroke patients. Black stroke patients may have a risk for CAD similar to that of their white counterparts.

Electrocardiographic findings in a middle-aged African population in the Seychelles islands

This study describes major electrocardiogram (ECG) measurements and diagnoses in a population of African individuals; most reference data have been collected in Caucasian populations and evidence exists for interethnic differences in ECG findings. This study was conducted in the Seychelles islands (Indian Ocean) and included 709 black individuals (343 men and 366 women) aged 25 to 64 years randomly selected from the general population. Resting ECG were recorded by using a validated ECG unit equipped with a measurement and interpretation software (Cardiovit AT-6, Schiller, Switzerland). The epidemiology of 14 basic ECG measurements, 6 composite criteria for left ventricular hypertrophy and 19 specific ECG diagnoses including abnormal rhythms, conduction abnormalities, repolarization abnormalities, and myocardial infarction were examined. Substantial gender and age differences were found for several ECG parameters. Moreover, tracings recorded in African individuals of the Seychelles differed from those collected similarly in Caucasian populations in many respects. For instance, heart rate was approximately 5 beats per minute lower in the African individuals than in selected Caucasian populations, prevalence of first degree atrio-ventricular block was especially high (4.8%), and the average Sokolow-Lyon voltage was markedly higher in African individuals of the Seychelles compared with black and white Americans. The integrated interpretation software detected "old myocardial infarction" in 3.8% of men and 0% of women and "old myocardial infarction possible" in 6.1% and 3%, respectively. Cardiac infarction injury scores are also provided. In conclusion, the study provides reference values for ECG findings in a specific population of people of African descent and stresses the need to systematically consider gender, age, and ethnicity when interpreting ECG tracings in individuals.

Electrocardiographic left ventricular hypertrophy by five criteria among civil servants in Benin City, Nigeria: prevalence and correlates

Although increasing hypertension rates have been reported in several African populations, little is known about the frequency of resulting hypertensive complications in these populations. We recorded the electrocardiograms of 482 male and 284 female civil servants in Benin City, Nigeria. Five different criteria were used to detect the presence of electrocardiographic left ventricular hypertrophy. Associations between electrocardiographic left ventricular hypertrophy and demographic, anthropometric and blood pressure characteristics were assessed. The prevalence of electrocardiographic left ventricular hypertrophy ranged from 3 to 29% in the total population, depending on the criteria used, with four of the five criteria resulting in prevalence estimates of less than 10%. The prevalence of electrocardiographic left ventricular hypertrophy was significantly greater among those with hypertension (19% of the total population), ranging from 11 to 49%. The prevalence of electrocardiographic left ventricular hypertrophy increased with blood pressure level in both normotensives and hypertensives. Among hypertensives with systolic blood pressure > or =180 mm Hg or diastolic blood pressure > or =110 mm Hg, the prevalence exceeded 50% by four of the five criteria. We conclude that left ventricular hypertrophy may be affecting many hypertensives in this Nigerian population, potentially resulting in a substantial future burden of cardiovascular disease and death.

Early repolarization

Early repolarization (ER) is an enigma. The purpose of this review is to reemphasize the overall electrocardiographic (ECG) pattern of this normal ST variant which continues to challenge the clinician because of its similarity to the current of injury potential to myocardium or an acute pericarditis. The data were provided from the studies identified through computerized searches of Medline, Toxline, Oxford, Agricola, and Bios Afterdark, Cumulative index, and a review of bibliographies of relevant articles on the related subjects. Early repolarization has elevated, upward, concave ST segments, located commonly in precordial leads, with reciprocal depression in a VR, tall, peaked and slightly asymmetrical T waves with notch, and slur on the R wave. The other accompanying features in the ECG are vertical axis, shorter and depressed P-R interval, abrupt transition, counterclockwise rotation, presence of U waves, and sinus bradycardia. Males dominate and patients are often younger than 50 years of age. The incidence of 1 to 2% is found equally common in all races. Degree and incidence of ST elevation decrease as age advances. Exercise or isoproterenol administration may normalize the ST segment. Early repolarization is a benign condition. If the ECG conforms to a classical pattern of ER on serial ECGs, it would exclude the unnecessary hazards of present day revascularization therapy for myocardial infarction such as primary angioplasty or thrombolytic therapy, or aggressive management of acute pericarditis, and so forth. This review concludes with a discussion of comparative ECG features of ER, pericarditis, and myocardial infarction, and provides an algorithm for diagnostic management of patients suffering from these conditions.

Early repolarization on scalar electrocardiogram

Sixty thousand electrocardiograms were analyzed for 5 years. Six hundred (1%) revealed early repolarization (ER). Features of ER were compared with race-, age-, and sex-matched controls (93.5% were Caucasians, 77% were males, 78.3% were younger than 50 years, and only 3.5% were older than 70). Those with ER had elevated, concave, ST segments in all electrocardiograms (1-5 mv), which were located most commonly in precordial leads (73%), with reciprocal ST depression (50%) in a VR, and notch and slur on R wave (56%). Other results included sinus bradycardia in 22%, shorter and depressed PR interval in 38%, slightly asymmetrical T waves in 96.7%, and U waves in 50%. Sixty patients exercised normalized ST segment and shortened QT interval (83%). In another 60 patients, serial studies for 10 years showed disappearance of ER in 18%, and was seen intermittently in the rest of the patients. The authors conclude that in these patients with ER: 1) male preponderance was found; 2) incidence in Caucasians was as common as in blacks; 3) patients often were younger than 50 years; 4) sinus bradycardia was the most common arrhythmia; 5) the PR interval was short and depressed; 6) the T wave was slightly asymmetrical; 7) exercise normalized ST segment; 8) incidence and degree of ST elevation reduced as age advanced; 9) possible mechanisms of ER are vagotonia, sympathetic stimulation, early repolarization of sub-epicardium, and difference in monophasic action potential observed on the endocardium and epicardium.

Ethnic differences in electrocardiographic left ventricular hypertrophy in young and middle-aged employed American men

In the United States population, black men have higher prevalence rates of electrocardiographic (ECG) high QRS voltage, more ST-segment and T-wave abnormalities, and more ECG left ventricular hypertrophy (LVH) than do white men. Reasons for these differences have not been fully elucidated. The prevalence rate of ECG LVH and associated characteristics were compared in black and white men in the Chicago Heart Association Detection Project in Industry population study. Data were from 1,391 black men and 19,126 white men (age range 20 to 64 years) employed by 84 Chicago organizations. ECG LVH was defined by the presence of both high QRS (Minnesota code 3.3) and ST-T abnormality (code 4.1-4.3 or 5.1-5.3). Black men had a significantly higher prevalence rate of ECG LVH than did white men in each 15-year age group (15.9 vs 2.4, 14.6 vs 2.8, and 35.7 vs 12.5/1,000 in the 20- to 34-, 35- to 49-, and 50-to 64-year age groups, respectively; p < 0.01 for each comparison). Multiple logistic regression analyses indicated that systolic blood pressure and age were associated positively with ECG LVH (p < 0.01) in both black and white men. Men with history of hypertension and receiving drug treatment had a greater likelihood of having ECG LVH than did those with history of hypertension but not receiving drug treatment, possibly because those with more severe hypertension were more likely to have been prescribed medication. Serum cholesterol, cigarettes smoked/day, 1-hour post-load plasma glucose and education were not consistently related to ECG LVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine vectocardiography: a comparative study relative to the validity of four tridimensional lead systems

For spatial vectocardiography to become applicable for cardiac investigation in cattle, it was necessary to develop a reliable standardized electrocardiographic lead system in this species. In this study, four tridimensional lead systems, initially developed in horses, were compared when applied in calves. Fifty seven electrocardiograms were collected. The between-subject variability of the magnitude and angles of the tridimensional P, QRS and T modal vectors obtained by use of each lead system was compared. Reproducibility of vectrocardiographic measurements was analyzed by comparing results obtained in 10 calves within a one day interval. The Holmes semi-orthogonal lead system, giving the lowest between-subject variability and the highest between-day reproducibility, appeared to be the most reliable lead system in order to apply vectocardiography in the bovine species.

Normal limits of the electrocardiogram in a Chinese population

12-lead electrocardiograms (ECGs) from 503 healthy Chinese individuals were computer-analyzed to derive the normal limits of the ECG in a Chinese population. With respect to ECG amplitudes, there were highly significant differences between men and women. The mean S wave amplitude in V2 decreased with increasing age, but the mean R wave amplitude in V5, for example, remained remarkably constant throughout the age groups. The QRS duration was on average 7.6 msec shorter in women than in men. The mean frontal QRS axis shifted superiorly by 17 degrees with increasing age, resulting in an upward trend in R wave amplitude in leads I and aVL. It was concluded that ECG diagnostic criteria for Chinese individuals should be age- and sex-dependent.

Macrovascular disease in diabetics in Central Africa

Six hundred African diabetics were examined for evidence of large vessel disease using a standardised technique based on the World Health Organisation Multinational Study, in which no country from Africa was represented. Twelve patients had electrocardiograms coded coronary probable using Minnesota coding. Seven patients had had strokes and 10 peripheral vascular disease. Despite the high prevalence of hypertension large vessel disease was uncommon, being comparable with Japan and Hong Kong, who had the lowest prevalence in the WHO study. Overall, only 49 patients had evidence of macrovascular disease.

Racial variations in electrocardiograms and vectorcardiograms between black and white children and their genesis

Despite a general clinical impression that the ECG of black children differs from that of white children, none of the normal standards in children have taken race into consideration. Biographic data, blood pressure, hemoglobin, ECG, Frank VCG and echocardiogram were obtained in 244 normal children (124 blacks and 120 whites) aged 3-17 years and 144 measured parameters and 57 computed variables were analyzed. The children were divided into age groups of 3-5, 6-10, 11-14, and 15-17 years. The 15-17 year age group was small and therefore excluded. In the 3-5-year age group there were no sex differences (p greater than 0.05) nor were there any differences (p greater than 0.05) observed between black and white children. No significant sex differences were seen in 6-10-year-olds. However, the amplitude of the R wave in lead I, S in V1 and V4, and the sums of SV1 and RV6 as well as SV1 and RV5 on the ECG, and X to the left and Y to the inferior on VCG were greater in black than in white children (p less than 0.01). In 11-14-year-olds many sex-related differences were seen in each race. R in leads I, II, AVL, AVF and V4, S wave in V1 and V4R, and the sums of SV1 and RV5 as well as SV1 and RV6 in the ECG, and Y inferior and Z anterior in the VCG were higher (p less than 0.01) in black males than white males. However, no differences (p greater than 0.05) were observed between black and white 11-14-year-old girls. To understand the causes of these differences, comparisons of the biographic data, blood pressure, hemoglobins and echocardiograms were made. The height, weight, body surface area, chest circumference, AP diameter of the chest, and diastolic and systolic blood pressure were similar (p greater than 0.1) in all groups. The hemoglobin level was lower in black than white children (p less than 0.05). However, this difference was seen in all age-sex subgroups, suggesting that hemoglobin level was not responsible for the ECG-VCG differences. The LV posterior wall in diastole was thicker and the anterior chest wall to mid-LV distance was shorter in black than in white children in age-sex subgroups in which ECG-VCG differences were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrocardiogram of the athlete: an analysis of 289 professional football players

The electrocardiogram (ECG) of athletes reflects physiologic cardiovascular adaptations that occur in well-conditioned individuals. To more clearly define electrocardiographic changes seen in predominantly power-trained athletes, the ECGs of 289 apparently healthy professional football players were analyzed in detail. The players, aged 21 to 35 years, one-third of whom were black, had a mean body surface area of 2.24 m2, a mean heart rate at rest of 56 +/- 9 beats/min (with 77% (223) having a rate of less than 60 beats/min), and a mean P axis of 30 +/- 25 degrees. A wide QRS-T angle (greater than 60 degrees) was present in 14% (41 players) of the group. The mean PR interval was 0.18 +/- 0.02 second (greater than 0.21 in 9% [26 players]). Although two-thirds of the players had a QRS duration of 0.10 second, only 1 had right bundle branch block and none had left bundle branch block. The sum of S in lead V1 plus R in lead V5 averaged 37 +/- 9 mm, with 35% (101 players) demonstrating voltage criteria for left ventricular hypertrophy. The S + R value varied inversely with weight (r = -0.27, p less than 0.002). The maximum T height in any lead had a mean of 8.6 +/- 3 mm, with 22% (64 players) having a T height greater than or equal to 11 mm. U waves were universally present. ST-T changes mimicking ischemia were noted in 39 of 289 players (13%), 22 (58%) of whom were black (p less than 0.001). The maximal J-point elevation in any lead averaged 1.9 +/- 0.9 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of normal variations in S-T segment patterns by body surface isopotential mapping: S-T segment elevation in absence of heart disease

S-T segment elevation is commonly observed in the electrocardiogram of normal persons. To study the possible origins of such patterns, 45 normal volunteers were examined. Electrocardiographic potentials were registered from 150 torso electrodes and processed to construct isopotential maps at 2 ms intervals throughout the QRS-T interval. The maximal potentials recorded from any of the 150 electrodes were 198 +/- 76.4 and 272.1 +/- 84.2 microV at instants 40 and 80 ms into the S-T segment, respectively. Maximal voltages recorded by the six standard precordial V leads at these respective time points were 109.7 +/- 57.0 and 163.6 +/- 66.9 microV. Torso maximal potentials were significantly stronger than were those sensed by V leads; the two were significantly correlated but predictability was limited. The duration of overlap between the onset of ventricular recovery and the end of the excitation was determined from isopotential maps and ranged rom 4 to 16 ms. There was no significant correlation (p greater than 0.05) between these values and either torso or V lead potentials at either 40 or 80 ms into S-T segment. These data suggest that (1) standard precordial leads do not accurately predict maximal torso potentials during the S-T segment, and (2) the degree of overlap between repolarization and depolarization is not a major determinant of precordial voltage. Hence, the rationale for use of the term "early repolarization" to describe this clinical condition is not substantiated.

Racial and sexual differences in the standard electrocardiogram of black vs white adolescents

Standard 12-lead electrocardiograms were recorded in 114 healthy adolescents to substantiate possible influences of race and sex on the "juvenile pattern" (increased precordial voltages of QRS complex, precordial T wave inversions, and ST-segment elevations considered pathologic in adults) in this age group. Black male subjects had the highest precordial QRS amplitudes and the highest incidence of biphasic or negative precordial T waves and ST-segment deviations. In white male subjects, these findings were less pronounced but were more evident than in black or white female subjects. Results indicate the following: (1) race-specific and sex-specific normal electrocardiographic standards should be developed in adolescents; (2) criteria for left ventricular hypertrophy are race-specific and sex-specific and should be tested against independent anatomic or physiologic information in adolescents with left ventricular overload; and (3) the "juvenile pattern" may be viewed as a predictable continuum of age-related changes starting in childhood and progressing through adolescence on to later life.

The athlete's heart syndrome: a new perspective

Although earlier electrocardiographic and roentgenographic studies suggested that the heart of trained athletes differed from that of nonathletes, little was known of the cardiac dimensions of the athlete's heart until the advent of echocardiography. Echocardiographic studies have demonstrated that trained athletes may have increased left ventricular mass and that the structural change accounting for this increase is related to the type of physical conditioning. Athletes participating primarily in isotonic exercise have an increase in left ventricular end-diastolic volume with little or no increase in left ventricular wall thickness whereas those athletes participating primarily in isometric exercise have an increase in left ventricular wall thickness associated with normal left ventricular end-diastolic volume. Comparisons between echocardiographically determined cardiac changes in college and world class athletes were made, and the electrocardiographic and chest roentgenographic changes present in the athlete's heart syndrome were reviewed.

Noninvasive evaluation of ventricular hypertrophy in professional athletes

Athletes often exhibit ECG findings which are considered to be abnormal. Therefore, we used noninvasive graphic methods to study 42 active professional male basketball players, ranging in age from 21 to 31 years, without clinically evident heart disease. Of the 42, 11 (25%) met the Romhilt-Estes ECG voltage criteria for left ventricular hypertrophy, and 12 (29%) satisfied VCG criteria for left ventricular enlargement; nine (21%) had left ventricular hypertrophy by both methods. In 33 subjects (79%) the 0.04 sec vector in the horizontal plane was anterior, and 29 of these exhibited one or more standard criteria for right ventricular enlargement; the ECG and VCG were concordant for right ventricular hypertrophy in 16 subjects (38%). Submaximal treadmill exercise tests (Bruce protocol) were normal in eight athletes, while in one subject ventricular premature beats occurred during the test. In 24 of 25 athletes (96%) from whom phonocardiograms were obtained a third heart sound was recorded, while in 14 (56%), a fourth heart sound was present. Of the 14 athletes who had a fourth heart sound, 12 (86%) had either ECG or VCG evidence of ventricular hypertrophy. Only four of 23 athletes had an increased cardiothoracic ratio (greater than .50) on routine chest X-ray. Ten athletes and ten control subjects matched for height, weight and body surface area had echocardiograms satisfactory for analysis. The left ventricular end-diastolic dimension in the athletes averaged 53.7 +/- 1.3 (SE) mm compared with a value of 49.9 +/- 0.7 mm in the control subjects (P less than 0.02), and was increased (greater than or equal to 56 mm) in four. Left ventricular posterior wall thickness averaged 11.1 +/- 0.6 mm, compared with a value of 9.8 +/- 0.5 mm in the control subjects (P less than 0.05), and was increased (greater than or equal to 11 mm) in six athletes. The right ventricular end-diastolic dimension averaged 20.8 +/- 1.1 mm compared with a value of 12.9 +/- 2.2 mm in the controls (P less than 0.004), and was increased (greater than or equal to 23 mm) in four athletes. No athlete or control subject exhibited paradoxical septal motion. In the athletes, ejection fraction (cube method) averaged 79 +/- 2.0% and mean Vcf averaged 1.13 +/- 0.04 circ/sec; these values did not differ from those of the control subjects. Thus, both right and left ventricular enlargement ("physiological hypertrophy") are often present in the well-trained athlete, but left ventricular performance remains normal in the basal state in such individuals. We condlude that these individuals represent a selected subgroup of subjects who are variants of normal.