Occurrence and Natural History of Clinically Silent Episodes of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Overt symptomatic atrial fibrillation (AF) occurs in over 20% of patients with hypertrophic cardiomyopathy (HC) leading to impaired quality of life, loss of productivity, and the risk for embolic stroke. However, the overall burden presented by AF in the HC population is unresolved due to the unknown frequency of silent asymptomatic episodes that do not necessarily achieve clinical recognition but nevertheless may have important disease-related implications. Therefore, stored electrograms were analyzed retrospectively for AF in 75 consecutive patients with HC (without AF history) implanted with dual-chamber cardioverter-defibrillators. Patients were followed for 5.0 ± 4.1 years at the Tufts Medical Center HCM Institute; ages were 50 ± 15 years, and 55% were male. Implantable cardioverter-defibrillator interrogation in the 75 patients showed AF to be absent in 54 (72%), 18 (24%) had clinically silent AF episodes, and the remaining 3 (4%) without previous asymptomatic episodes developed symptomatic and clinically overt paroxysmal AF. Of the 18 patients with clinically silent AF, 8 developed symptomatic AF, 4.1 ± 1.5 years later. Nonfatal embolic stroke occurred in 1 patient associated with asymptomatic AF and without other risk factors. In conclusion, clinically silent AF appears to be common in HC, occurring in almost 25% of patients. Such asymptomatic episodes of AF have important future implications, including potential thromboembolic risk, and development of symptomatic and clinically overt AF requiring prophylactic anticoagulation.

American Heart Association Response to the 2015 Institute of Medicine Report on Strategies to Improve Cardiac Arrest Survival

The American Heart Association (AHA) commends the recently released Institute of Medicine (IOM) report, Strategies to Improve Cardiac Arrest Survival: A Time to Act (2015). The AHA recognizes the unique opportunity created by the report to meaningfully advance the objectives of improving outcomes for sudden cardiac arrest. For decades, the AHA has focused on the goal of reducing morbidity and mortality from cardiovascular disease though robust support of basic, translational, clinical, and population research. The AHA also has developed a rigorous process using the best available evidence to develop scientific, advisory, and guideline documents. These core activities of development and dissemination of scientific evidence have served as the foundation for a broad range of advocacy initiatives and programs that serve as a foundation for advancing the AHA and IOM goal of improving cardiac arrest outcomes. In response to the call to action in the IOM report, the AHA is announcing 4 new commitments to increase cardiac arrest survival: (1) The AHA will provide up to $5 million in funding over 5 years to incentivize resuscitation data interoperability; (2) the AHA will actively pursue philanthropic support for local and regional implementation opportunities to increase cardiac arrest survival by improving out-of-hospital and in-hospital systems of care; (3) the AHA will actively pursue philanthropic support to launch an AHA resuscitation research network; and (4) the AHA will cosponsor a National Cardiac Arrest Summit to facilitate the creation of a national cardiac arrest collaborative that will unify the field and identify common goals to improve survival. In addition to the AHA’s historic and ongoing commitment to improving cardiac arrest care and outcomes, these new initiatives are responsive to each of the IOM recommendations and demonstrate the AHA’s leadership in the field. However, successful implementation of the IOM recommendations will require a timely response by all stakeholders identified in the report and a coordinated approach to achieve our common goal of improved cardiac arrest outcomes.