An interesting finding was the early onset and severity of hypertension such as to induce cardiomegaly in the age group 20–29. Notable amongst the causes of hypertension of renal origin was chronic glomerulonephritis which was 3 times that due to chronic pyelonephritis. Ischaemic heart diseases constituted 3.3% of cases, of which one-third (1.1%) was acute myocardial infarction which therefore continues to be an uncommon causes of death in Ghana. Overall, 47.8% of deaths from cardiomegaly were under 50 years of age. The young age at death could therefore be a factor in the lower rate of ischaemic heart diseases.

Hudson² have the following useful guide to fresh heart weight. Adult heart weight is reached between the ages of 17 and 23 years. Adult male heart weights, 0.45% body weight, average 300grams, range 250–350 grams. Adult female heart weight, 0.40% body weight, averages 250grams, range 200–300 grams. Waller et al⁷ in an autopsy study of 40 subjects concluded that increased heart weight was more than 350grams in women and more than 400grams in men. For purposes of this study, a heart weight of 400grams in both sexes was chosen because Ghanaian females on average have a higher body mass index (BMI) 25.6 ± 5.8 compared to 22.6 ± 3.9 for men⁸. In an autopsy study involving 2219 South African blacks who died of heart diseases in 1959, 1960 and 1976, the commonest form of heart disease encountered was hypertensive heart disease and by far the majority of these cases were of essential hypertension⁹. Myocardial infarction was rare, but rheumatic heart disease was common affecting young people who often had advanced valvular lesions by puberty⁹.

The records of all autopsies performed within the stated period were retrieved and checked against the documented cases for completeness. Where there had been an omission to document a case with heart weight of 400 grams or more, the cardiomegaly book was updated. Where essential information was missing, the original autopsy sheet was retrieved and the necessary information ascertained.

The study was entirely macroscopic with all its accepted limitations. The diagnosis of hypertensive cardiomegaly was made by a combination of the features of the heart and benign nephrosclerosis of the kidney, in addition to available clinical information. In all the cases of cardiomyopathy, the kidneys were essentially uninvolved.

Cardiomegaly (heart weight ≥ 400grams) was recorded in 11.4% of autopsies in 1998 (403/3541), 12.4% in 1999 (444/3567) and 12.8% in 2000 (472/3684). Over the 3 year period, 12.2% of autopsies performed revealed a cardiomegaly. There was a greater preponderance of cardiomegaly among the hospital autopsy cases than the coroners autopsy cases - 21.8%:8.1% (1998), 24.8%:9.0% (1999) and 24.9%:10% (2000). On average, cardiomegaly was 2.5 times commoner in a hospital autopsy than a coroner's autopsy (p<0.05 for each of the three years).

The modal and median age group was 50–59 years when both sexes were considered together and also when separated. Significantly, 46.8% of the deaths with cardiomegaly in this study were younger than 50 years of age (Table 1).

The male to female ratio was 1.85:1. The male preponderance was true for all the age groups except at the extremes, ≤19 and ≥80 years. This deduction must take into consideration the fact that cardiomegaly in females starts at 350 grams. The male-female ratio would probably not be significant if all those had been taken into consideration. A body weight and heart weight analytic study is proposed.

The heart weight and sex distribution are shown in Table 2. There were 66.6% of cases with heart weight below 550grams.

The cause of cardiomegaly in the majority (55%) of cases in this study was essential hypertension (Table 3). Hypertension of renal origin (Renal hypertension) accounted for 23.4% of cases. Hypertension (both essential and secondary to renal pathology) therefore accounted for almost 4 out of every 5 cases of cardiomegaly in this study (78.4%). Pregnancy induced hypertension (PIH, including eclampsia) accounted for only 8 of the 1034 cases of hypertension.

Of the 309 cases of renal hypertension, 57% (176/309) were due to chronic glomerulonephritis, 19.7% (61/309) due to chronic pyelonephritis, 7.4% (23/309) due to diabetic nephropathy (in persons clinically diabetic and not previously known to be hypertensive), 4.6% (14/309) due to obstructive uropathy, 3.2% (10/309) due to bilateral polycystic kidney and 2.3% (7/309) from bilateral renal papillary necrosis (all due to Sickle Cell Disease). In 5.8% (18/309), no underlying cause for the end stage renal disease was stated at autopsy. It could itself be the end result of essential hypertension (hypertensive nephropathy), since all the above renal diagnoses were macroscopic.

The criteria for diagnosis of chronic glomerulonephritis was uniform bilateral reduction in size of kidneys to within a third to half of normal, in addition to features of end stage kidney. In view of the absence of microscopy in the study, the chronic glomerulonephritides group could not be subclassified.

Of the 80 cases of cardiomypathy, 47.5% (38/80), 40% (32/80) and 5% (4/80) were due to dilated, hypertrophic and restrictive (all diagnosed as endomyocardial fibrosis) cardiomyopathy respectively, with the remaining 7.5% (6/80) having no stated type. Notably, all the cases of hypertrophic and restrictive cardiomyopathy were younger than 40 years, whilst most (30 out of 38) of the cases of dilated cardiomyopathy were 40 years or older.

Thirty-five percent (21/60), 30% (18/60, 25% (15/60) and 10% (6/60) of the 60 cases of cor pulmonale with cardiomegaly were due to chronic asthma, chronic emphysema, chronic pulmonary thromboembolism and massive bilateral pulmonary embolism respectively. Of the total 60 cases of cor pulmonale, there were 29 males and 31 females, giving an almost balanced sex distribution. Fifty out of the 60 cases (84%) were older than 50 years of age.

Chronic rheumatic heart disease (CRHD) accounted for 3.6% (48/1318) of all the cases of cardiomegaly, and all except 3 out of the total of 48cases of CRHD were younger than 50 years. In contrast, all the 43 cases were recent infarcts (acute myocardial infarction).

Twenty-two of the 24 cases of chronic severe anaemia with cardiomegaly were in Sickle Cell Anaemia patients whilst the remaining two were cases of multiple myeloma. Of the ten cases of congenital heart disease with cardiomegaly, 3 had a Ventricular Septal Defect (VSD), another 3 had both VSD and Atrial Septal Defect (ASD), 2 had large ASD whilst the remaining two had Tetralogy of Fallot (TOF).

Since adult heart weight is attained between 17 to 23 years² (with a mean of 20 years i.e. 20±3 years), we assessed the causes for premature cardiomegaly (Table 4).

Primary hypertension causing cardiomegaly was noted as early as the 20–29 year group (34 out of 725). This confirms the already known fact that the hypertension in blacks starts at a younger age¹⁴. A heart weight of 400 grams or more in the 20–29 year group further attests to the known fact that hypertension is severer among blacks¹⁵.

In Ghana, the prevalence of hypertension has been put between 8% to 13% among urban adults, compared to only 4.5% among rural adults, however, the prevalence was 29% for persons aged 35 and older, compared to 3.9% for persons under 35 years of age¹⁶. The impact of hypertension therefore is of the magnitude that makes it a major public health problem.

Hypertension of renal origin contributed 30% (309 out of 1034) of the total cases of hypertension-induced cardiomegaly, and chronic glomerulonephritis was the major cause of renal hypertension. The three-fold increase in chronic glomerulonephritis as compared to chronic pyelonephritis requires further investigation as usually both diseases appear of equal prominence¹⁷.

Work done in black populations in the UK, USA and West Africa show hypertensive nephropathy as the major cause of end stage renal disease (ESRD)^17–21.

Although this work looked at the heart as the target organ, it would appear from the numbers that in looking at the kidney as the target organ, this work would support that assertion. This would be in contrast to findings in the Caucasian population where chronic glomerulonephritis is the major cause of ESRD^22,23.

The distribution of the types of cardiomyopathy found in our study is at variance with that of Attah²⁴ who clearly states that hypertrophic cardiomyopathy is rare in Africans. Cardiomyopathy was an important cause of cardiomegaly. Notably, hypertrophic cardiomyopathy appeared of equal prominence as dilated cardiomyopathy, with only 5% from restrictive cardiomyopathy. In view of the fact that our study was entirely macroscopic, there is the need to repeat the study with histological and chromosomal analysis to determine the true prevalence of hypertrophic cardiomyopathy.

Cor pulmonale contributed 4.6% of cases distributed between chronic obstructive lung diseases such as chronic asthma and emphysema, and pulmonary thromboembolism. Cor pulmonale from chronic obstructive airway disease and thromboembolism occurred in an older age group, and unlike other populations the sex distribution was almost equal. The age distribution of the cor pulmonale cases is in agreement with work done by a WHO Expert Committee, however, our almost equal sex distribution is in sharp contrast to their five-fold increase in men²⁵. It will be interesting to know whether in view of the increased use of tobacco among women in recent years, their sex distribution is valid today.

Curiously, 10% (6/60) of the cor pulmonale cases were attributable to massive bilateral pulmonary embolism, which is essentially an acute event. What was not stated though was whether the cardiomegaly was entirely right-sided or left-sided or both. It is not inconceivable that some of these cases had underlying hypertension.

Chronic rheumatic heart diseases made up 3.6% of the cases, and are still a youthful disease as most of the patients were in the 20–49 year group, as in South African Blacks⁹. It clearly indicates that acute rheumatic fever continues to be a problem despite its near eradication in the developed world.

Ischaemic heart disease accounted for 3.3% of the case, of which about one-third were recent infarcts. Interestingly, acute myocardial infarction as a cause of death continues to be uncommon in Ghana, as in South African Blacks⁹. The young age of death in this study could be a source of explanation, since 46.8% of cases in this study died of cardiomegaly before age 50.

Also significant was the number of cases attributable to sickle cell anaemia. Ghana has a high prevalence of sickle cell anaemia (SS) and sickle cell disease (SC). Preliminary results of an ongoing screening of newborn infants in Kumasi, Ghana stated the prevalence of the sickle cell S gene as 2% (unpublished report). Chronic anaemia from sickle cell disease will continue to pose a problem in Ghana as the commonest genetic disease.