Practice Update: Cardiology

AHA 2016 25

Dr Clyde Yancy on current diagnostic and therapeutic strategies for dilated cardiomyopathy Clyde W Yancy MD, MSc, MACC, FAHA, MACP is Associate Director at Bluhm Cardiovascular Institute, Northwestern Memorial Hospital in Chicago. T he American Heart Association brings forward Scientific Statements in lieu of Clinical Practice Guidelines when there is a topical issue for which clinical and mechanistic insight is needed, but insufficient data are available to offer a formal guideline. This is such a document; we cannot expect large-scale randomised clinical trials to be completed for specific cardiomyopathies when the frequency is low and known direct therapeutic inter- ventions are few. Yet, direction is needed. As a co-author of the American Heart Association Scientific Statement, “Current Diagnostic and Treatment Strategies for Specific Dilated Cardiomyopathies,” we have provided the direction needed to better enable diagnosis, treatment planning, and importantly, to provide the information needed for the physician-patient discussion for those patients with a dilated cardiomyopathy. The following are several high points from the statement. Context In clinical practice, the presence of left ventricular dysfunction with reduced ejection fraction in the absence of coronary artery disease allows for the diagnosis of a dilated cardiomyopathy which is oft times attributable to an idiopathic or “cause unknown” aetiology. Though this was useful 20 years ago, it is no longer relevant and is frankly obsolete. Patients are driven to know “why” heart failure or a cardiomyopathy is present. Increasingly, a specific cause leading to the phenotype of a dilated cardiomyopathy can be elucidated which in turn will highlight either an important prognostic perspective or a potential therapeutic intervention unique to the pathology. In 2016–2017 we should not miss the opportunity to provide a clear diagnosis for a dilated cardiomyopathy. Breath This statement provides an expansive survey of the large number of specific aetiologies, including infiltrative (eg, amyloidosis, sarcoidosis), cardiotoxic (eg, alcohol, illicit substance abuse and chemotherapeutic use), peripartum, myocarditis, infectious (HIV, Chagas), autoimmune, metabolic, obesity-related, endocrine, tachycardia related, conduction system related (LBBB), Taka-tsubo’s (stress-induced), paediatric, and especially genetic. When brought together in one document, the list is quite comprehensive. Each condition is fully developed with diagnostic criteria, epidemiology and unique therapeutic considerations. Consider this your dilated cardiomyopathy reference document and a “go-to” even before doing a literature search and certainly before doing a Google-enabled search. Use Relying on memory is no longer the preferred information repository in medical decision- making. Few of us are facile with the unique diagnostic considerations for many of these conditions so the discussions, particularly for those conditions we are more likely to see –amyloidosis, sarcoidosis, chemotherapeutic exposure and genetic – are useful. In today’s environment, the physician-patient dialogue is expected. Using this document as a point of reference, those discussions are now better informed and much more authentic. Remember, when you next see a dilated cardiomyopathy, there may be an identifiable cause. I urge you to relegate “idiopathic” to your diagnostic category of last resort and instead have this document within your frequently utilised references.

Current diagnostic and treatment strategies for specific dilated cardiomyopathies: a scientific statement from the American Heart Association Circulation Take-home message • This is a report on the current understanding of dilated cardiomyopathy by the AHA. Current diagnostic and therapeutic strategies are stressed and are based on important cause of heart failure, and treatment needs to be individualized based on the aetiology. ABSTRACT The intent of this American Heart Association (AHA) scientific statement is to summarize our current understanding of dilated cardiomyopathies. There is special emphasis on recent developments in diagnostic approaches and therapies for specific cardiomyopathies. Recommendations in this document are based on published studies, published practice guidelines from the American College of Cardiology (ACC)/AHA and other organizations, and themultidisciplinary expertise of the writing group. Existing evidence in epidemiology, classification, diagnosis, and management of specific cardiomyopathies is usually derived from nonrandomized observational studies, registries, case reports, or expert opinion based on clinical experience, not large- scale randomized clinical trials or systematic reviews. Therefore, in this document, rather than using the standard ACC/AHA classification schema of recommendations and level of evidence, we have included key management strategies at the end of each section and categorized our recommendations according to the level of consensus. Although the format of our recommendationsmight resemble theACC/ AHA classification of recommendations used in the ACC/AHA practice guidelines, because of the preponderance of expert opinion or level of evidence C evidence in our document, we elected to use different terminology to provide a distinction from the practice guidelines, in which stronger levels and quality of evidence with randomized clinical trials or meta-analyses are usually present. The levels of evidence follow the AHA and ACC methods of classifying the level of certainty of the treatment effect. Circulation 2016 Nov 03;[Epub ahead of print], Bozkurt B, Colvin M, Cook J, et al observational studies, case reports, and expert opinion. Published guidelines from the ACC and AHA as well as other organisations also contribute to the recommendations in this report. • Dilated cardiomyopathy is an

DECEMBER 2016