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By definition, patients with heart failure and preserved ejection fraction are characterized by a normal or near-normal left ventricular ejection fraction, but marked heterogeneity in the extent of other cardiac structural and functional abnormalities exists. Improved appreciation of this diversity might provide insights into prognosis and therapeutic interventions.
The concept that raising HDL-cholesterol level will uniformly translate into cardiovascular risk reduction has been challenged by genetic epidemiology studies and large-scale, randomized clinical trials. Studies suggest that we should go beyond HDL cholesterol, and consider emerging biomarkers of HDL concentration, composition, and functionality as surrogates for cardiovascular risk reduction.
Amin and colleagues have attempted to estimate the cost savings to the US health-care system if drug-eluting coronary stents were more selectively used in patients at low risk of restenosis. Their results and conclusions raise statistical, societal, and ethical issues that need to be considered before this approach should be widely embraced.
Abnormalities in the control of intracellular calcium are involved in several forms of inherited arrhythmias. The genetic mutations that cause these abnormalities have generated much research interest in the past decade. Here, Venetucci et al. provide an overview of the structural organization and the function of calcium-handling proteins and describe the mechanisms by which mutations determine the various clinical phenotypes of calcium channelopathies.
Chagas disease is endemic in Latin America, but the migration of infected individuals makes the condition an increasingly global problem. The authors review the epidemiology, pathogenesis, diagnosis, and treatment of the disease, focusing particularly on the risk stratification and management of patients with Chagas cardiomyopathy.
Syncope is a transient, self-terminating period of cerebral hypoperfusion that usually results from systemic hypotension. Many patients with this condition are successfully treated according to current guidelines. However, the authors identify and expertly review the current understanding of four key challenges in the characterization, diagnosis, risk stratification, and treatment of patients with suspected syncope.
Despite advances in prevention of cardiovascular disease, a high proportion of cardiac events occur in asymptomatic people who do not have a high level of risk. Much remains unknown about the value of novel risk markers for the identification of candidates for primary prevention. Here, Polonsky and Greenland argue that clinical trials of these markers in asymptomatic, low-risk populations are greatly needed to determine their effectiveness.
A major problem in Central and South America, Chagas disease is now also affecting individuals residing in other parts of the world. Many patients with late-stage disease have chronic cardiomyopathy and associated arrhythmias. In this Perspectives article, Professor Benaim and Dr Paniz Mondolfi discuss the potential for amiodarone and dronedarone to be used as dual-action (antiarrhythmic and antiparasitic) agents in patients with Chagas disease.