Genetic mutations in African patients with atrial fibrillation: Rationale and design of the Study of Genetics of Atrial Fibrillation in an African Population (SIGNAL).

BACKGROUND: There is an urgent need to understand genetic associations with atrial fibrillation in ethnically diverse populations. There are no such data from sub-Saharan Africa, despite the fact that atrial fibrillation is one of the fastest growing diseases. Moreover, patients with valvular heart disease are underrepresented in studies of the genetics of atrial fibrillation. METHODS: We designed a case-control study of patients with and without a history of atrial fibrillation in Kenya. Cases with atrial fibrillation included those with and without valvular heart disease. Patients underwent clinical phenotyping and will have laboratory analysis and genetic testing of >240 candidate genes associated with cardiovascular diseases. A 12-month follow-up assessment will determine the groups' morbidity and mortality. The primary analyses will describe genetic and phenotypic associations with atrial fibrillation. RESULTS: We recruited 298 participants: 72 (24%) with nonvalvular atrial fibrillation, 78 (26%) with valvular atrial fibrillation, and 148 (50%) controls without atrial fibrillation. The mean age of cases and controls were 53 and 48 years, respectively. Most (69%) participants were female. Controls more often had hypertension (45%) than did those with valvular atrial fibrillation (27%). Diabetes and current tobacco smoking were uncommon. A history of stroke was present in 25% of cases and in 5% of controls. CONCLUSION: This is the first study determining genetic associations in valvular and nonvalvular atrial fibrillation in sub-Saharan Africa with a control population. The results advance knowledge about atrial fibrillation and will enhance international efforts to decrease atrial fibrillation-related morbidity.

Early cardiac dysfunction in children and young adults with perinatally acquired HIV.

OBJECTIVE: To define the prevalence of early cardiac dysfunction in children and young adults with perinatally acquired HIV and predictors of cardiac function. DESIGN: Cross-sectional design. METHODS: Early cardiac dysfunction was defined as left ventricular (LV) global longitudinal strain z-score less than -2 or myocardial performance index at least 0.5 with normal LV ejection fraction. Regression models were fitted to assess the relationship between measures of cardiac function and HIV RNA levels, clinical variables, and markers of inflammation. RESULTS: Six hundred and forty-three individuals (mean age 14.1 ±â€Š5.2 years) were enrolled. The average time on combination antiretroviral treatment was 6.8 ±â€Š3.6 years. Nearly 28% of individuals met criteria for early cardiac dysfunction. Individuals with early cardiac dysfunction were older (15.3 vs. 13.5 years, P < 0.001), had more frequently detectable HIV RNA (52.5 vs. 41.7%, P = 0.018), were more likely exposed to azidothymidine or zidovudine (ZDV) (55.6 vs. 41.2%, P = 0.002), and had higher median level of plasma IL-6 concentrations (1.00 vs. 0.88 pg/ml, P = 0.011). Multivariable models show LV ejection fraction negatively associated with HIV RNA levels [ß -0.18; 95% confidence interval (CI) -0.33, -0.03] and ZDV exposure (ß -1.75; 95% CI -2.62, -0.88) and positively associated with proportion of life on combination antiretroviral treatment (ß 2.65; 95% CI 0.90, 4.41). Higher myocardial performance index was positively associated with serum inflammation marker (IL-6 ß 0.01; 95% CI 0.0001, 0.001). Left ventricular global longitudinal strain was not significantly associated with clinical and laboratory variables of interest. CONCLUSION: Over one-quarter of children and young adults living with HIV demonstrated evidence of cardiac dysfunction, which may be associated with increasing levels of systemic inflammation.

Clinical characteristics and 12-month outcomes of patients with valvular and non-valvular atrial fibrillation in Kenya.

BACKGROUND: Atrial fibrillation (AF) is a major contributor to the global cardiovascular disease burden. The clinical profile and outcomes of AF patients with valvular heart diseases in sub-Saharan Africa (SSA) have not been adequately described. We assessed clinical features and 12-month outcomes of patients with valvular AF (vAF) in comparison to AF patients without valvular heart disease (nvAF) in western Kenya. METHODS: We performed a cohort study with retrospective data gathering to characterize risk factors and prospective data collection to characterize their hospitalization, stroke and mortality rates. RESULTS: The AF patients included 77 with vAF and 69 with nvAF. The mean (SD) age of vAF and nvAF patients were 37.9(14.5) and 69.4(12.3) years, respectively. There were significant differences (p<0.001) between vAF and nvAF patients with respect to female sex (78% vs. 55%), rates of hypertension (29% vs. 73%) and heart failure (10% vs. 49%). vAF patients were more likely to be taking anticoagulation therapy compared to those with nvAF (97% vs. 76%; p<0.01). After 12-months of follow-up, the overall mortality, hospitalization and stroke rates for vAF patients were high, at 10%, 34% and 5% respectively, and were similar to the rates in the nvAF patients (15%, 36%, and 5%, respectively). CONCLUSION: Despite younger age and few comorbid conditions, patients with vAF in this developing country setting are at high risk for nonfatal and fatal outcomes, and are in need of interventions to improve short and long-term outcomes.