Risk Stratification for Sudden Cardiac Death

The role of cardiorespiratory fitness on the risk of sudden cardiac death at the population level: A systematic review and meta-analysis of the available evidence

Cardiorespiratory fitness (CRF) has been widely studied as a powerful and independent predictor of all-cause and disease-specific mortality. Sudden cardiac death (SCD) is recognized as a significant cause of mortality among the general population, including the general population without previous symptoms of any coronary heart disease (CHD). Consequently, SCD is an important public health problem, which constitutes a clinical challenge. Thus, prevention of SCD by detecting early risk factors could be a useful tool, contributing to the American Heart Association's goal of decreasing the incidence of SCD at the population level. The identification of these risk factors for CVD would facilitate the large-scale screening of those participants at higher risk of SCD. This systematic review collects information about the role of CRF on the risk of SCD at the available evidence, and analyzes the long-term influence of CRF as a risk factor and independent predictor of SCD.

Randomized trials, observational registries, and the foundations of evidence-based medicine

Although randomized trials and observational studies are used as the evidentiary basis of clinical practice guidelines, they are not always in agreement. Limitations in the process of randomization in the former and the selective referral of patients for treatment as a consequence of clinical "risk stratification" in the latter are underappreciated causes for these disagreements. As a result, neither is guaranteed to correctly quantify treatment benefit. This essay reviews the operational differences between these alternative evidentiary sources and shows how these differences can affect individual clinical decisions, population-based practice guidelines, and national health policy. In conclusion, the process of evidence-based medicine can be improved by independent agencies charged with the responsibility to identify and resolve these differences.