A recent paper in the New England Journal of Medicine  examined data on 156,424 people from 17 countries. It demonstrated that although a mean cardiovascular risk score (INTERHEART) was highest in high-income countries, intermediate in middle-income countries, and lowest in low-income countries, the rates of major cardiovascular disease and death were substantially higher in low-income countries than in high-income countries.
Previous work has shown that improvements in medical and surgical treatments (including secondary prevention, heart failure treatments, initial treatments of myocardial infarction, anti-hypertensives and treatment of hypercholesterolaemia) are responsible for 40-55% of the total decrease in cardiovascular mortality (depending on country and time-period studied) while trends in risk factors (including reductions in total cholesterol, systolic blood pressure and smoking) account for 30-60% of the total reduction in cardiovascular mortality.   
It is necessary to tackle the relatively high burden of cardiovascular risk factors in high-income countries through Public Health programmes and policy, but the NEJM paper suggests that increased access to high-quality health care and more frequent use of proven pharmacological and surgical therapies may reduce disease burden in low- and middle-income countries. Increases in the prevalence of cardiovascular risk factors (smoking, obesity, diabetes) in low- and middle-income countries, in the context of continued poor access to high-quality health care could have severe consequences.
— Oyinlola Oyebode, Associate Professor in Public Health
- Yusuf S, Rangarajan S, Teo K, et al. Cardiovascular Risk and Events in 17 Low-, Middle-, and High-Income Countries. N Eng J Med. 2014; 371(9): 818-27.
- Unal B, Critchely JA, Capewell S. Explaining the Decline in Coronary Heart Disease Mortality in England and Wales Between 1981 and 2000. Circulation. 2004; 109: 1101-7.
- Ford ES, Ajani UA, Croft JB, et al. Explaining the decrease in U.S. deaths from coronary disease, 1980-2000. N Engl J Med. 2007; 356(23): 2388-98.
- Wijeysundera HC, Machado M, Farahati F, et al. Association of temporal trends in risk factors and treatment uptake with coronary heart disease mortality, 1994-2005. JAMA. 2010; 303(18): 1841-7.
- Bajekal M, Scholes S, Love H, et al. Analysing Recent Socioeconomic Trends in Coronary Heart Disease Mortality in England, 2000–2007: A Population Modelling Study. PLoS Med. 2012; 9(6): e1001237.