Previous workers have postulated a geochemical basis for endomyocardial fibrosis. Endomyocardial fibrosis of tropical origin is a disease where the endocardium of either the right or the left ventricle, or both gets progressively thickened and the ventricles get obliterated. The fibrosis of the endocardium also extends into the subendocardial myocardium and hence the name tropical endomyocardial fibrosis. Various aetiologies’ have been postulated for endomyocardial fibrosis including rheumatic fever,toxic damage due to eosinophils (degranulated eosinophils), or due to cyanides in tubers, as the histological picture is similar to that seen In hypereosinophilic syndrome, Loffler’s endocarditis and in eosinophilic leukaemia.
Endomyocardial fibrosis was reported from the early 1970s from Kerala. Two regions were commonly in the news, Trivandrum and Alleppey. Trivandrum is a coastal town with more government offices and no industry, and a relatively more backward lower socioeconomic class. Nearly every one had small pockets of land. They would cultivate tapioca, a tuber, or yam or sweet potatoes that they would eat with fish or a chutney, when they could not afford rice.
Long ago pulses were not easily available and were not eaten as much as they are eaten now. So the average Kerala population would not eat much protein. Trivandrum has more laterite soil and a more city based life. Alleppey is a coastal town with both access to the sea as well as to a large back water sea salt containing lake making access to fish easy. The two geographies are different. Alleppey is often water logged, and it is claimed that nothing like rice or simple crops like tapioca,or bananas can grow there. So of necessity the major food of most of the common man contains an amount of fish.
So it would be interesting to compare whether the pattern of endomyocardial fibrosis is different in the two parts of Kerala. That was the main aim of this study.
Compared to the patients already reported in The Medical Treatment of Endomyocardial Fibrosis we had 6 more patients with endomyocardial fibrosis detected after the previous paper. But these patients form part of another report so they are not included in this study. The same original 154 patients (of which 3 more died) were compared to the newer 49 patients with endomyocardial fibrosis collected from Alleppey Medical College during the period 2012 to 2014. All patients were assessed by echocardiography and the diagnosis was made based on Shapers’s criteria or Mocumbi criteria.
The mean age at first presentation to the hospital of the Alleppey patients was 51.3+- 11.9 years(N = 49). The mean age of Trivandrum patients was − 51.9+-14.3 years. (NS) In Alleppey there were 31 females and 18 males.(63% vs 37% respectively). In Trivandrum also there were 98/154 females(63.6%) and 56 males (36.36%)(Chi square NS.)
The distribution of the types of endomyocardial fibrosis were different in Alleppey and Trivandrum . Alleppey had significantly more right ventricular endomyocardial fibrosis than Trivandrum. (61% vs 33%) p < 0.001.Trivandrum had significantly more biventricular endomyocardial fibrosis. p < 0.001 (64.9% versus 14.3%).
There was a significant difference in the percentage of patients presenting with the first symptom below the age of 30 years. (a) The distribution of variables in patients − Left Ventricular endomyocardial fibrosis in Alappuzha and Trivandrum. (b) The distribution of variables in patients − RV −ventricular endomyocardial fibrosis in Alappuzha and Trivandrum.
Briefly the l year, 3 years and 6 years survival of Alleppey patients was 100%, 95% and 91.5% respectively while the survival from Trivandrum at the same intervals was 93.5% at 1 year, 72.2% at three years and 61.7% at six years. (p < 0.0001)
Recent papers on endomyocardial fibrosis seem to show that endomyocardial fibrosis is slowly vanishing and is aging18–20. But no other study had compared the pattern of endomyocardial fibrosis presenting to two centres separated by a distance.
In contrast the Trivandrum population tends to eat sardines, and other locally available fish and a larger quantity of tubers like cassava, high in carbohydrate and low in protein diets. Due to the high rainfall, the soil is laterite, that is inherently deficient in magnesium. So this population tends to be more malnourished and probably has more severe endomyocardial fibrosis. The magnesium content of sardines, mackerel and anchovies are less than that found in prawns.
Tuna also has been found to have higher quantities of mercury that is harmful, but this does not have any relationship to endomyocardial fibrosis. One more interesting finding in this study is the range of the total counts of the patients. In general the total counts were normal and not significantly different in Trivandrum or Alleppey. But if the range of the total count (WBC count) are taken some patients had very low total counts like 800/cmm or 950/cmm .Workers have previously reported this finding in endomyocardial fibrosis. But we were not the first to notice this, Andrade and Guimaraes had already commented on the same. We believe this, and the presence of anaemia reflect the toxicity of cerium or some unknown toxin on the bone marrow.
Of note is another survey by British workers. They studied the cerium levels in various populations in Uganda. In this study the Cerium and magnesium levels in the soil and water were studied in areas where endomyocardial fibrosis was prelevant.It has been believed to be more common in those who eat regular tubers like cassava. So a recent report from Cameroon is of interest. Chelo studied the hospital records of the Mother and Child Centre of the Chantal Biya Foundation (MCC/CBF) in Cameroon. (Yaonade). He examined the hospital records of consulations and echocardiography between January 2006 and December 2014.During this period he surveyed 273117 consultations and detected 1666 cases of heart disease and 54 cases of endomyocardial fibrosis.
All these consultations were done in children below the age of 16 years. The percentage of endomyocardial fibrosis was only 3.24% of all heart diseases seen. Most of the patients came from 3 regions in Cameroon and 76% were from rural areas. The age range was from 2 years to 17 years. Most of the patients ate Cassava more than 6 times a week, rarely ate vegetables or fish. The other food they ate were plantains and coco-yams.No family had a car. Only 8.3% had a fridge. Only 8.3% had running water.66% had no electricity. From 2006, 32/54 patients died.(59%) No fish consumption at all was noted by the workers.7/54 (12.96%) had atrial fibrillation and 2 had atrial flutter. This population is akin to the Trivandrum population reported by us. Previous studies in endomyocardial fibrosis have shown that atrial fibrillation, or atrial arrhythmia is an important factor contributing to early mortality. Since the mean age of both Alleppey and Trivandrum patients was identical it is surprizing the incidence of atrial fibrillation was higher in the Trivandrum population. However as previously discussed it is possible that the higher incidence of Biventricular endomyocardial fibrosis is responsible for the higher atrial fibrillation and the higher mortality of Trivandrum patients.