Current Diagnostic and Treatment Strategies for Specific Dilated Cardiomyopathies: A Scientific Statement From the American Heart Association

Abstract

CLINICAL STATEMENTS AND GUIDELINEST he 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 1 and other organizations, 2,3 and the multidisciplinary 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, 4 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 recommendations might resemble the ACC/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. 4 The levels of evidence follow the AHA and ACC methods of classifying the level of certainty of the treatment effect. 4 DEfINITIoN of DILATED CArDIoMyopAThyThe term dilated cardiomyopathy (DCM) refers to a spectrum of heterogeneous myocardial disorders that are characterized by ventricular dilation and depressed myocardial performance in the absence of hypertension, valvular, congenital, or ischemic heart disease. 5 In clinical practice, the pathogenesis of heart failure (HF) has often been placed into 2 categories: ischemic and nonischemic cardiomyopathy. The term nonischemic cardiomyopathy has been interchangeably used with DCM. Although this approach might be practical, it fails to recognize that nonischemic cardiomyopathy can include cardiomyopathies caused by volume or pressure overload (such as hypertension or valvular heart disease) that are not conventionally accepted under the definition of DCM. 1,5 Again, in general practice and clinical research trials, the term ischemic cardiomyopathy is defined as cardiomyopathy caused by ischemic heart disease. Current use of ischemic cardiomyopathy terminology implies ventricular dilation and depressed myocardial contractility caused by ischemia or infarction. CLASSIfICATIoN of CArDIoMyopAThIESThe first classification on this topic categorized cardiomyopathies as heart muscle diseases with dilated (DCM), hypertrophic, restrictive, arrhythmogenic right ventricular (ARVC), or nonclassifiable cardiomyopathy in 1980. 5 Subse...

Tead1 is required for maintaining adult cardiomyocyte function, and its loss results in lethal dilated cardiomyopathy

“…Dilated cardiomyopathy (DCM) -a form of heart failure with diminished cardiac contractility, dilated ventricular chambers, myocyte death, and myocardial fibrosis (2) -has a has a prevalence of 1 in 2,500 (3, 4) and a high 5-year mortality of 50% (4). DCM may result from defects in diverse cellular processes, including those resulting from ischemia/injury and familial genetic defects.…”

Cardiac Magnetic Resonance Imaging in Myocarditis Reveals Persistent Disease Activity Despite Normalization of Cardiac Enzymes and Inflammatory Parameters at 3-Month Follow-Up

“…Therefore, its use is limited to a selected group of patients as outlined by the American Heart Association/American College of Cardiology guidelines. 23,24 These include patients with heart failure requiring inotropic or mechanical circulatory support, Mobitz type 2 second degree or higher heart block, sustained or symptomatic ventricular tachycardia, or failure to respond to guideline-based therapy within 1 to 2 weeks. 23,24 For all other patients with suspected myocarditis, a synopsis of clinical history and noninvasive testing is preferred.…”

Peripartum cardiomyopathy

“…Echocardiography may also show right ventricular dilatation and dysfunction, pulmonary hypertension, left atrial or biatrial enlargement, functional mitral and tricuspid regurgitation, and intracardiac thrombus 1381…”

“…CMR imaging may be helpful diagnostically when echocardiography is technically limited 82. Magnetic resonance imaging at 1.5 Tesla is thought to be safe in pregnancy, although guidelines discourage the use of gadolinium, which crosses the placenta and may be teratogenic 8182. Computed tomography imaging has not been studied in PPCM but can rule out other conditions that may present as dyspnea in a peripartum patient, such as pulmonary embolism.…”