Obesity Cardiomyopathy as a Cause of Sudden Cardiac Death

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lished by the Association for European Cardiovascular Pathology. 2Cases with coronary artery disease, hypertrophic cardiomyopathy, hypertension, or valvular heart disease were excluded.In obese subjects, there were 53 cases of unexplained cardiomegaly and in normal weight subjects there were 14 cases.The odds ratio for cardiomegaly in obesity was 5.3 (95% CI: 2.9-9.6;P < 0.001).Subjects who were obese and had cardiomegaly were defined as obesity cardiomyopathy (OCM). 1 OCM cases had a mean age of 42 AE 12 years, were mostly men (64%) with a mean BMI of 42 AE 8 kg/m 2 and a mean heart weight of 598 AE 93 g.In comparison to matched normal weight and obese controls, the OCM group had increased epicardial fat and uniformly greater left ventricular (LV) wall thickness.All OCM subjects had myocyte hypertrophy, but only 13% had fibrosis on histology, and none had myocyte disarray. 1is study has important implications considering the global burden of obesity and the socioeconomic consequences of the loss of these young productive members of society.The prevalence of obesity in children continues to rise across the globe.In 1975, only 4% of children aged 5 to 19 were overweight or obese and in 2016 18% of children were overweight or obese. 3It is very difficult to lose and maintain weight once it is gained and obese children are likely to be obese adults. 4Obesity in childhood is associated with a greater risk and earlier onset of cardiovascular disease and diabetes.One in 5 adults in the world is expected to be obese by 2025. 3 This report adds to a body of literature suggesting that left ventricular hypertrophy (LVH) due to obesity is a risk factor for SCD. 5,6A recent paper from Australia compared obese vs nonobese SCD victims ages 18 to 50 years. 6Although they did not exclude subjects with comorbid conditions, only 10% of victims with a BMI >50 kg/m 2 had coronary disease while two-thirds had LVH.The definition of LVH in that study was similar; 400 g in females or 500 g in males in the presence of any wall diameter >15 mm. 6e strength of the current study is that subjects were younger and coexistent conditions were excluded. 1In the past, the adverse cardiovascular risk associated with obesity was attributed to comorbidities such as diabetes mellitus, sleep apnea, and metabolic syndrome.However, we know that obesity imparts a strong and independent risk of incident heart failure. 7The paper suggests that morbid obesity also imparts an independent risk of SCD, particularly in individuals with a BMI >35 kg/m 2 . 1   In Figure 2 If so, a practical definition or cutoff for OCM using left ventricular mass would be needed.
Practicing cardiologists are more familiar with estimates of left ventricular mass, not total heart weight.To put the findings of this study in context, consider the normal values for myocardial mass as measured by echocardiography and MRI. 14,15The upper limits of normal indexed LV mass by echocardiography are 88 g/m 2 in women and 102 g/m 2 in men. 15In cardiac MRI, the upper limits of normal are 68 g/m 2 in women and 85 g/m 2 in men.The limitations of both imaging modalities are beyond the scope of this paper but transthoracic echocardiogram is an overestimation and MRI is closer to the true value. 14Consider an average of the two, 78 g/m 2 in women and 95 g/m 2 in men.The left ventricle accounts for w55% of total heart weight at autopsy. 16ing this value, the estimated LV mass indices in the Westaby et al 1 cohort were w100 g/m 2 in normal and obese controls and w131 g/m 2 in OCM.In addition to the increased mass, the wall thickness of the OCM group was high, suggestive of concentric LVH, a common finding in obese patients that has been validated by MRI.Health systems need to be more aggressive in the identification and treatment of obesity in childhood and the medical and surgical treatment of severe obesity in young adulthood.Prevention efforts would be bolstered by legislation on a local and global scale that ensures: 1) everyone has access to healthy and affordable food options; 2) screen time is limited; and 3) physical activity is encouraged.

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The author has reported that he has no relationships relevant to the contents of this paper to disclose.
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Fitzgibbons
, 1 the authors show the histology of 1 OCM case that has fatty infiltration of the left ventricle.They do not mention what percentage of