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West Indian Medical Journal

versão impressa ISSN 0043-3144

West Indian med. j. v.56 n.2 Mona mar. 2007

http://dx.doi.org/10.1590/S0043-31442007000200006 

ORIGINAL ARTICLES

 

Sensitivity and specificity of the electrocardiogram in predicting the presence of increased left ventricular mass index on the echocardiogram in Afro-Caribbean hypertensive patients

 

Sensibilidad y especificidad del electrocardiograma en la predicción de la presencia de aumento del indice de masa ventricular izquierda en el ecocardiograma en pacientes Afro-caribeños hipertensos

 

 

TC MartinI, II, III, IV; YG BhaskarI; KV UmeshI

IThe Cardiology Service, Holberton Hospital, St John’s Antigua
IIThe Antigua Heart Centre, Belmont Clinic, All Saint’s Road, Antigua
IIIThe American University in Antigua College of Medicine, St John’s, Antigua
IVThe University of Rochester School of Medicine and Dentistry, Rochester, New York,USA

Correspondence

 

 


ABSTRACT

Cardiovascular disease is emerging as the leading cause of death in the Caribbean region with hypertension along with diabetes mellitus representing the major causes. Left ventricular hypertrophy associated with hypertension results in a two to fourfold increase in cardiac morbidity and mortality. One hundred and eleven patients, 67% female, mean age 46 years with a mean of seven years since diagnosis, had resting blood pressure, electrocardiogram and sector-focused M-mode echocardiogram performed. The electrocardiograms were analyzed for left ventricular hypertrophy using Sokolow-Lyon, Cornell, Romhilts-Estes, 12 lead sum, QRS duration, 12 lead–QRS product and left ventricular strain pattern. The echocardiograms were analyzed for increased left ventricular mass using the formula of Devereux and Reichek indexed to height. The mean systolic blood pressure was 156 mmHg, mean diastolic blood pressure was 97 mmHg on treatment. At least one electrocardiographic criterion for left ventricular hypertrophy was seen in 47/111 (42%) patients and increased left ventricular mass index was seen in 55/111 (50%) patients. Sensitivity, specificity and positive predictive value of the electrocardiogram in predicting increased left ventricular mass index was best for Sokolow-Lyon (31%, 86%, 76%), Cornell (23%, 96%, 88%) and 12 lead-QRS product (30%, 86%, 72%). Sensitivity ranged from 3 to 31%, specificity from 80 to 96% and positive predictive value from 40 to 88%. The electrocardiogram is insensitive in detecting increased echocardiographic left ventricular mass index, as in patients from developed countries, and is less specific for the finding as in African Americans.


RESUMEN

La enfermedad cardiovascular está pasando a ocupar el primer plano como causa principal de muertes en la región del Caribe, siendo la hipertensión junto con la diabetes las causas principales. La hipertrofia del ventrículo izquierdo asociada con los resultados de la hipertensión, trae como consecuencia que la morbilidad y la mortalidad cardíacas aumenten de dos a cuatro veces. A ciento once pacientes – el 67% mujeres, con una edad promedio de 46 años y un promedio de siete años transcurridos desde el diagnóstico – se les midió la presión arterial en reposo, y se les hizo un electrocardiograma, así como un ecocardiograma en Modo-M enfocado por sectores. Los electrocardiogramas fueron analizados en busca de alguna hipertrofia ventricular izquierda, usando los criterios de Sokolow-Lyon, Cornell, Romhilts-Estes, la suma de 12 derivaciones, la duración del QRS, el producto del QRS en las 12 derivaciones, y el patrón de tensión ventricular izquierda. Los ecocardiogramas fueron analizados fueron analizados en busca de un aumento de la masa ventricular izquierda, usando la fórmula de Devereux y Reichek indexada por la altura. La media de la presión arterial sistólica fue 156 mmHg, y la media de la presión arterial diastólica fue 97 mmHg en el tratamiento. Al menos un criterio electrocardiográfico de la hipertrofia ventricular izquierda fue visto en 47/111 (42%) pacientes, y el índice de masa ventricular izquierda aumentada, fue visto en 55/111 (50%). La sensibilidad, especificidad y valor predictivo positivo del electrocardiograma en la predicción del índice de masa ventricular izquierda aumentada fue mejor en Sokolow-Lyon (31%, 86%, 76%), Cornell (23%, 96%, 88%) y el producto del QRS en las 12 derivaciones (30%, 86%, 72%). La sensibilidad fluctuó del 3 al 31%; la especificidad, del 80 al 96%; y el valor predictivo positivo, del 40 al 88%. El electrocardiograma es insensible en cuanto a detectar el índice de masa ventricular izquierda aumentada, como en el caso de pacientes de países desarrollados, y es menos específico para el hallazgo, como en el caso de los afro-norteamericanos.


 

 

INTRODUCTION

Cardiovascular disease is emerging as the most frequent cause of death in the Caribbean, with cerebrovascular disease (13.0%), ischaemic heart disease (9.5%), hypertensive disease (4.8%) and diabetes mellitus (8.4%) accounting for 35.5% of the mortality in the region in 1990 (1). The same diseases accounted for 47.2% of the deaths in Antigua and Barbuda in 1998 (2). Available data suggest that hypertension is present in 40% of the Caribbean population by age 40 years and 50% by age 65 years (3). Hypertension has been found to be the leading factor associated with congestive cardiac failure, myocardial infarction, atrial fibrillation and cerebrovascular accident in Afro-Caribbean patients (4–10).

Hypertensive heart disease is defined as the response of the heart to the afterload imposed on the left ventricle by increased arterial pressure and peripheral resistance produced by hypertensive vascular disease. The degree of left ventricular hypertrophy is related to the arterial pressure and is an ominous prognostic sign and independent risk factor for sudden death, ventricular arrhythmias, myocardial ischaemia, coronary artery disease, congestive cardiac failure and cerebrovascular accident (11–15).

Hypertensive patients of African ethnicity in the United States of America (USA) have a higher risk for hypertension related morbidity and mortality, a higher prevalence of hypertension, more left ventricular hypertrophy and more congestive cardiac failure and stroke than patients of European ethnicity (13–16). Although high blood pressure and its consequences had been less of a problem in Africa and the Caribbean for patients of African ethnicity (19–21), changing diet and lifestyles are increasing the risks to the Caribbean patient of African ethnicity (22–24).

The presence of left ventricular hypertrophy may be assessed by electrocardiography and echocardiography, with the newer techniques of computed tomography and magnetic resonance imaging being applied recently (25). The electrocardiogram and echocardiogram have the most substantial support for clinical use (25). The electrocardiogram is relatively insensitive to left ventricular hypertrophy, identifying only 30 to 50% of patients with left ventricular hypertrophy on echocardiogram (26–28).

Electrocardiographic left ventricular hypertrophy is specific for echocardiographic left ventricular hypertrophy in 90 to 95% of persons of European ethnicity but appears less so for Afro-American and Afro-Caribbean patients (29–33). Echocardiographic left ventricular hypertrophy is seen in a majority of mild to moderate hypertensive patients (34), is accurate using necropsy findings for confirmation (35), and is an independent risk factor for cardiovascular complications, increasing risk by a factor of four in patients of European and African ethnicity (36–38).

There are few data concerning the prevalence of left ventricular hypertrophy on electrocardiogram or echocardiogram in Afro-Caribbean patients with hypertension. This study is an attempt to describe the electrocardiographic findings in a sample of treated hypertensive patients in Antigua, and assess the ability of the electrocardiogram to predict echocardiographic left ventricular hypertrophy in this population.

 

SUBJECTS AND METHODS

Afro-Caribbean patients with hypertension were invited to participate in an evaluation of left ventricular hypertrophy in hypertension in Antigua and Barbuda. Participants were recruited from the district clinics in Antigua as well as from the offices of medical practitioners. All recruited patients were diagnosed previously with hypertension and were receiving medical treatment through their primary caretakers. These medications were continued during the study.

Following the study explanation, informed consent for participation was obtained. Patients with congestive cardiac failure or renal failure were excluded. All patients had age, gender, height, weight, medications and other risk factors such as tobacco and drug use, diabetes and anaemia recorded. Blood pressure was taken with a mercury sphygmomanometer according to recommendations (39). This was followed by an electrocardiogram performed on a Burdick instrument (Burdick, Inc, Milton, Wisconsin USA, 1995) and measured by hand. An echocardiogram was performed by a single investigator (TCM) unaware of clinical or electrocardiographic findings. The echocardiograms were performed on a Toshiba Sonolayer SSA-100 machine (Toshiba, Inc, Tokyo, Japan, 1988) with a 3.25 megaHertz transducer. Sector-focused M-mode images were measured from video images showing the best left ventricular image. Electrocardiograms were analyzed for left ventricular hypertrophy using established criteria (27, 28, 30, 40, 41).

Sokolow-Lyon: S in lead V1 plus R in lead V5 or V6 over 35 millimetres (mm). Cornell: R in lead AVL plus S in lead V3 over 24 min in men, over 20 mm in women. Romhilts-Estes: R or S in limb lead over 20 mm, S in V1, V2 or V3 over 25 mm or R in V4, V5 or V6 over 25 mm = 3 points; any ST shift = 3 points (with digoxin = 1 point); Left axis deviation less than -15 degrees = 2 points; QRS duration 0.09 second or over = 1 point; intrinsicoid deflection in V5 or V6 over 0.04 second = 1 point, P wave terminal force in V1 over 0.04 second = 3 points. Left ventricular hypertrophy is present if total points equal or exceed 5.

12-Lead sum: sum of all QRS deflections over 179 mm QRS duration: QRS duration in any lead over 0.12 second (120 milliseconds, msec). 12-Lead-QRS product: product of 12-Lead sum multiplied by QRS duration over 17,472 mm-msec. Left ventricular strain: depressed ST segment with upward convexity to negative T wave.

Echocardiographic analysis included measurement of the left ventricular internal diameter (LVID) in diastole, the left ventricular internal diameter in systole (LVIS), the posterior left ventricular wall thickness (PWT), and the intra-ventricular septal thickness (IVS) according to established criteria (42–44). Patients with decreased left ventricular systolic function, with left ventricular fractional shortening (LVID – LVIS divided by LVID less than 0.25, were excluded. Left ventricular mass was calculated using the method of Devereux and Reichek (45): left ventricular mass (in grams, g) = 1.04 [ (LVID + IVS + PWT)3 – (LVID)3 ] – 13.6. This value was divided by the height in metres (m) to give the left ventricular mass index. Increased left ventricular mass index was defined as over 143 g/m2 in men and over 102 g/m2 in women. Concentric left ventricular hypertrophy was defined as IVS + PWT divided by 0.5 x+ LVID greater than 0.44 with increased left ventricular mass index (46, 47). Concentric remodelling was defined as IVS + PWT divided by 0.5 x LVID greater than 0.44 with normal left ventricular mass index (46, 47).

Using the echocardiographic finding of increased left ventricular mass index as the most definitive diagnostic finding associated with cardiovascular events in hypertension, the sensitivity, specificity, positive predictive value and negative predictive value of each electrocardiographic criterion for left ventricular hypertrophy was assessed. Sensitivity is the number of patients with electrocardiographic left ventricular hypertrophy and echocardiographic left ventricular hypertrophy divided by the number with echocardiographic left ventricular hypertrophy with or without electrocardiographic left ventricular hypertrophy (true positive divided by true positive plus false negative) x 100. Specificity is the number of patients with no electrocardiographic left ventricular hypertrophy and no echocardiographic left ventricular hypertrophy divided by the number with no echocardiographic left ventricular hypertrophy (true negative divided by true negative plus false positive) x 100.

Positive predictive value is the number of patients with electrocardiographic left ventricular hypertrophy and echocardiographic left ventricular hypertrophy divided by the number with echocardiographic left ventricular hypertrophy with or without electrocardiographic left ventricular hypertrophy (true positive divided by true positive plus false positive) X 100. Negative predictive value is the number of patients with no electrocardiographic or echocardiographic left ventricular hypertrophy divided by the number without electrocardiographic left ventricular hypertrophy with or without echocardiographic left ventricular hypertrophy (true negative divided by true negative plus false negative) x 100.

 

RESULTS

A total of 131 patients were enrolled in the project. There were 111 (85%) with complete data for analysis, the most frequent reason for dropout being technically inadequate transthoracic echocardiographic study. There were 74/111 (67%) women, 37/111 (33%) men, with mean age 46.3 years (range 27 to 69 years). The mean duration of known hypertension was 7.6 years (range 1 to 30 years). The mean systolic blood pressure was 156 ± 22 millimeters of mercury (mmHg) and the mean diastolic pressure was 97 ± 12 mmHg. There were 47/111 (42%) who met at least one criterion for electrocardiographic left ventricular hypertrophy. There were 55/111 (50%) patients who had increased left ventricular mass index on echocardiogram.

The sensitivity of the electrocardiogram for predicting echocardiographic left ventricular hypertrophy varied from 3% for the QRS duration to 31% for the Sokolow-Lyon criterion (Table). There were 7/111 patients (5%) less than the 35 years of age used to validate the Sokolow-Lyon criteria but this did not make a difference to the outcome. The 12-lead QRS product had value of 30% with the Cornell criterion 23%. The specificity of the electrocardiogram for predicting increased left ventricular mass varied from 96% for the Cornell criterion to 80% for the 12 lead sum. The 12 lead QRS product was 86% (Table).

 

 

The positive predictive value for any of the electrocardiographic criteria predicting increased echocardiographic left ventricular mass index was 57%. The Cornell criteria had the highest positive predictive value, 88%, followed by Sokolow-Lyon at 76% and 12 lead-QRS product at 72%. The negative predictive value (that a normal electrocardiogram predicted the absence of increased echocardiographic left ventricular mass index) was 47%.

Of those patients with increased left ventricular mass index, 42/55 (76%) had concentric left ventricular hypertrophy and 13/55 (24%) had eccentric hypertrophy. Of those patients having normal left ventricular mass index, 39/56 (69%) had concentric remodelling and 17/56 (31%) were normal.

 

DISCUSSION

Although Sokolow-Lyon, Cornell and 12 lead-QRS duration product have some usefulness compared to other criteria for predicting echocardiographic confirmed left ventricular hypertrophy (31, 41, 47), sensitivity is low. This sensitivity is worse for patients of African ethnicity (28–31) and is poor for Afro-Caribbean patients as documented in this study, with maximum sensitivity for any criteria of left ventricular hypertrophy less than 33%. Attempts have been made to improve the sensitivity of the electrocardiogram using more complicated formulae in all patients (28, 48) and Afro-American patients specifically (49), but are not widely used.

Specificity of the electrocardiogram in this sample was in the 80% range for most criteria, with the Cornell criteria at specificity of 96% but with a sensitivity of only 23%. The results of this study do confirm that of the routinely available electrocardiographic criteria for left ventricular hypertrophy, the Sokolow-Lyon, Cornell and 12 lead-QRS product have the best combination of sensitivity, specificity and positive predictive value for predicting increased echocardiographic left ventricular mass.

In addition to lack of sensitivity and, to a lesser extent, specificity, the electrocardiogram had a positive predictive value of 57% and a negative predictive value of 47% in this sample of Afro-Caribbean hypertensive patients. The current recommendation in the Caribbean is to use the electrocardiogram to assess the hypertensive patient for left ventricular hypertrophy (39). Although the left ventricular hypertrophy on the electrocardiogram is an independent predictor of untoward outcome (13, 50), the echocardiographic left ventricular hypertrophy is also an independent predictor (13, 50), one that may have increased usefulness in the Afro-Caribbean hypertensive patient. Echocardiography may be the tool of choice for assessing cardiac involvement in hypertension, despite the cost.

This study has several limitations. The number of patients involved in the study is small. The electrocardiogram is less effective in the elderly (51) and in obese patients(52) in predicting left ventricular mass but the data from these groups were not analysed separately. The left ventricular mass index can be done by different methods (eg indexed to body surface area or height to the 2.7 power) but in this study 2/111 (2%) of patients would have been classified differently if values were indexed to body surface area and a recent review suggested that due to high correlation, indexing by any method was nearly equivalent (53). The simplest method was chosen.

In summary, this study demonstrates that the electrocardiogram lacks sensitivity for detecting increased echocardiographic left ventricular mass in a sample of Afro-Caribbean hypertensive patients, as it also does in hypertensive patients in developed countries. In addition, the specificity is similar to that seen in hypertensive patients of African ethnicity overseas, and is less than that for hypertensive patients of European ethnicity. For these reasons, echocardiography appears more accurate than electrocardiography and might be considered the tool of choice for assessing cardiovascular and cerebrovascular risk in hypertensive patients in the Caribbean region.

 

ACKNOWLEDGEMENTS

The contribution of the referring doctors and nurses and the cooperation of the administration of Holberton Hospital in St John’s, Antigua, is appreciated. We are grateful to the patients for their time and cooperation. The authors thank Dr RB Devereux for providing reprints of his published manuscripts and the Caribbean Health Research Council for its support.

 

REFERENCES

1. Holder Y, Lewis MJ. Epidemiological overview of morbidity and mortality. In: Health Conditions in the Caribbean. Scientific publication No. 561. Pan American Health Organization, Washington DC, USA 1997: 22–61.

2. Health Information Division. Mortality. In: Health Statistical Digest 1999 Edition. Health Information Division, Ministry of Health, Government of Antigua and Barbuda, St John’s, Antigua 2000: 20–30.

3. Fraser HS. Treatment of hypertension for all before the year 2000. West Indian Med J 1993; 42 (Suppl 3): 22.

4. McSwain M, Martin TC, Amaraswamy R. The prevalence, aetiology and treatment of congestive cardiac failure in Antigua and Barbuda. West Indian Med J 1999; 48: 137–40.

5. Martin TC. M-mode echocardiographic findings in a contemporary Afro-Caribbean population referred for evaluation of congestive cardiac failure. West Indian Med J 2002; 51: 93–6.

6. Martin TC, Van Longhuyzen HW, Amaraswamy R, Tangutoori R, Bennett B. Myocardial infarction in Antigua 1990-95. West Indian Med J 1997; 46: 76–9.

7. Khetan S, Maharaj R, Davis GK. Management of acute myocardial infarction in the public sector in the Bahamas. West Indian Med J 2000; 49: 115–7.

8. Besterman E. Lessons from reporting 100 000 Jamaican electrocardiograms. West Indian Med J 2000; 49: 123–7.

9. Martin TC. Echocardiographic findings in a contemporary Afro-Caribbean population referred for evaluation of atrial fibrillation and flutter. West Indian Med J 2001; 50: 294–6.

10. Martin TC. M-mode echocardiographic findings in an Afro-Caribbean population referred after a stroke. West Indian Med J (Abstract) 2004; 53 (Suppl 2): 69–70.

11. Frohlich ED, Apstein C, Chobanian AV Devereux RB, Dustan HP, Dzau V et al. The heart in hypertension. N Engl J Med 1992; 327: 998–1008.

12. Porter JN, Petch MC. Hypertension and the heart. Post Grad Doctor Carib 1994; 10: 124–8.

13. Aronow WS, Ahn C, Kronzon I, Koenigsberg M. Congestive heart failure, coronary events and atherothrombotic brain infarction in elderly blacks and whites with systemic hypertension with and without echocardiographic and electrocardiographic evidence of left ventricular hypertrophy. Am J Cardiol 1991; 67: 295–9.

14. Gardin JM, Brunner D, Schreiner PJ, Xie X, Reid CL, Ruth K et al. Demographics and correlates of five-year change in echocardiographic left ventricular mass in young black and white adult men and women: the coronary artery risk development in young adults (CARDIA) study. J Am Coll Cardiol 2002; 40: 529–35.

15. East MA, Jollis JG, Nelson CL, Marks D, Peterson ED. The influence of left ventricular hypertrophy on survival in patients with coronary artery disease: do race and gender matter? J Am Coll Cardiol 2002; 41: 949–54.

16. Gardin JM, Wagenknecht LE, Anton-Culver H, Flack J, Gidding S, Kurosaki T et al. Relationship of cardiovascular risk factors to echocardiographic left ventricular mass in healthy young black and white adult men and women. The CARDIA study. Circulation 1995; 92: 380–7.

17. Haider AW, Larson MG, Benjamin EJ, Levy D. Increased left ventricular mass and hypertrophy are associated with increased risk for sudden death. J Am Coll Cardiol 1998: 32: 1454–9.

18. van den Hoogen PC, Feskins EJ, Nagelkerke NJ, Menotti A, Nissinen A, Kromhout D. The relation between blood pressure and mortality due to coronary heart disease among men in different parts of the world. Seven countries study Research Group. N Engl J Med 2000; 342: 1–8.

19. Akinkugbe OO. High blood pressure in the African context. Tropical Doctor 1980; 10: 56–8.

20. Cooper R, Rotimi C, Ataman S, McGee D, Osotimehin B, Kadiri S et al. The prevalence of hypertension in seven populations of West African origin. Am J Public Health 1997; 87: 160–8.

21. Fang J, Madhavan S, Alderman MH. The association between birthplace and mortality from cardiovascular causes among black and white residents of New York City. N Engl J Med 1996; 335: 1545–51.

22. Liqui Lung AFL, de Windt-Hol JMC, Steward HN, Muskiet FAJ. Hypertension in the Afro-Caribbeans of Curacao: its prevalence and the implications. Carib Health 2001; 4 (Suppl); 23–4.

23. Hennis A. Hypertension in the Caribbean. Post Grad Doctor Carib 1999; 15: 148–54.

24. Stuart LM. Hypertension in the Afro-Caribbean patient: update. Post Grad Doctor Carib 2000; 16: 198–204.

25. Lorell BH, Carabello BA. Left ventricular hypertrophy. Pathogenesis, detection and prognosis. Circulation 2000; 102: 470–9.

26. Reichek N, Devereux RB. Left ventricular hypertrophy: relationship of anatomic, echocardiographic and electrocardiographic findings. Circulation 1981; 63: 1391–8.

27. Okin PM, Roman MJ, Devereux RB, Kligfield P. Electrocardiographic identification of increased left ventricular mass by simple voltage duration product. J Am Coll Cardiol 1995; 25: 417–23.

28. Crow RS, Prineas WL, Rautaharju P, Hamman P, Liebson PR. Relationship between electrocardiography and echocardiography for left ventricular mass in mild systemic hypertension. Am J Cardiol 1995; 75: 1233–8.

29. Cumming GR, Proudfit WL. High voltage QRS complexes in the absence of left ventricular hypertrophy. Circulation 1959; 19: 406–11.

30. Lee DK, Marantz PR, Devereux RB, Klingfield P, Alderman MH. Left ventricular hypertrophy in black and white hypertensives. Standard electrocardiographic criteria overestimate racial differences in prevalence. JAMA 1992; 267: 3294–9.

31. Foucan L, Haddad A, Genevier I, Samuel Y, Salmi RL. Sokolow-Lyon voltage criteria in sickle cell patients. West Indian Med J 1999; 48: 132–6.

32. Patrick AL, Boyd-Patrick HA. Selected cardiovascular risk factors and electrocardiographic findings. A Tobago study. West Indian Med J 1985; 34: 80–9.

33. Patrick AL, Boyd-Patrick A, Henry R, Ince W, Holder Y, Bunker C. Left ventricular hypertrophy: a common finding in adult African population in Tobago, West Indies. West Indian Med J 1995 (Abstract); 44 (Suppl 3): 20.

34. Levy D, Savage DD, Garrison RJ, Anderson KM, Kannel WB, Castelli WP. Echocardiographic criteria for left ventricular hypertrophy: the Framingham Heart Study. Am J Cardiol 1987; 59: 956–60.

35. Devereux RB, Alonso DR, Lutas EM, Gottlieb GJ, Campo WE, Sachs I et al. Echocardiographic assessment of left ventricular hypertrophy: comparison with necropsy findings. Am J Cardiol 1986; 57: 450–8.

36. Levy D, Garrison RJ, Savage DD, Kanell WB, Castelli WP. Prognostic implications of echocardiographically determined left ventricular mass in the Framingham Heart Study. N Engl J Med 1990; 322: 1561–6.

37. Casale PN, Devereux RB, Milner M, Zullo G, Harshfield GA, Pickering TG et al. Value of echocardiographic measurement in predicting cardiovascular morbid events in hypertensive men. Ann Intern Med 1986; 105: 173–8.

38. Liao Y, Cooper RS, Mensah GA, McGee DL. Left ventricular hypertrophy has a greater impact in women than men. Circulation 1995; 92: 805–10.

39. Commonwealth Caribbean Medical Research Council. Establishing the diagnosis of hypertension. In: Managing Hypertension in Primary Care in the Caribbean. CCMRC, Port-of-Spain, Trinidad and Tobago 1998: 1–5.

40. Marriott RJL. Left ventricular hypertrophy. In: Practical Electrocardiography, 8th ed, Williams and Wilkins, Baltimore, Maryland, USA 1988: 50–8.

41. Malloy TJ, Okin PM, Devereux RB, Klingfield P. Electrocardiographic detection of left ventricular hypertrophy by the simple QRS voltage-duration product. J Am Coll Cardiol 1992; 20: 1180–6.

42. Henry WL, Gardin JM, Ware JH. Echocardiographic measurements in normal subjects from infancy to old age. Circulation 1980; 62: 1054–61.

43. Sahn DJ, DeMaria A, Kisslo J, Weyman A. Recommendations regarding quantitation in M-mode echocardiography: results of a survey of echocardiographic measurements. Circulation 1978; 58: 1072–83.

44. ACC/AHA Task Force Report. ACC/AHA guidelines for the clinical application of echocardiography. A report of the American College of Cardiology/ American Heart Association task force on assessment of diagnostic and therapeutic cardiovascular procedures (subcommittee to develop guidelines for the clinical application of echocardiography). J Am Coll Cardiol 1990; 16: 1505–28.

45. Devereux RB, Reichek N. Echocardiographic determination of left ventricular mass in man. Anatomic validation of the method. Circulation 1977; 55: 613–8.

46. Verdecchia P, Schillaci G, Borgioni C, Ciucci A, Battistelli M, Bartoccini C et al. Adverse prognostic significance of concentric re-modeling of the left ventricle in hypertensive patients with normal left ventricular mass. J Am Coll Cardiol 1995; 25: 871–8.

47. Ganau A, Devereux RB, Roman MJ, de Simone G, Pickering TG, Saba PS et al. Patterns of left ventricular hypertrophy and geometric remodeling in essential hypertension. J Am Coll Cardiol 1992; 19: 1550–8.

48. de Vries SO, Heeson WF, Beltman FW, Kroese AH, May JF, Smit AJ et al. Prediction of the left ventricular mass from the electrocardiogram in systemic hypertension. Am J Cardiol 1996; 77: 974–8.

49. Arnett DK, Rautaharju P, Sutherland S, Usher B, Keil J. Validity of the electrocardiographic estimates of left ventricular hypertrophy and mass in African Americans (the Charleston Heart Study). Am J Cardiol 1997; 79: 1289–92.

50. Sundstrom J, Lind L, Arnlov J, Zethelius B, Andren B, Lithell HO. Echocardiographic and electrocardiographic diagnoses of left ventricular hypertrophy predict mortality independently of each other in a population of elderly men. Circulation 2001; 103: 2346–51.

51. Yamashita S, Dohi Y, Miyagawa K, Kojima M, Sato K. Reliability of the electrocardiogram for detecting left ventricular hypertrophy in the elderly. Am J Cardiol 1998; 81: 650–2.

52. Abergel E, Tase M, Menard J, Chatellier G. Influence of obesity on the diagnostic value of electrocardiographic criteria for detecting left ventricular hypertrophy. Am J Cardiol 1996; 77: 739–44.

53. Liao Y, Cooper RS, Durazo-Arvizu R, Mensah GA, Ghali JK. Prediction of mortality risk by different methods of indexation for left ventricular mass. J Am Coll Cardiol 1997; 29: 641–7.

 

 

Correspondence:
Dr TC Martin
PO Box W879
Woods Centre, Antigua
Fax: (268) 462-5258
e-mail: martint@candw.ag