RT Book, Section A1 Towbin, Jeffrey A. A2 Kline, Mark W. SR Print(0) ID 1182914397 T1 Diseases of the Myocardium T2 Rudolph's Pediatrics, 23e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259588594 LK accesspediatrics.mhmedical.com/content.aspx?aid=1182914397 RD 2024/10/04 AB The myocardium can be affected by genetic, inflammatory, metabolic, infiltrative, ischemic, or primary disease processes, with significant overlap for many of them (Table 483-1). Myocardial diseases may present acutely, with signs of decompensated heart failure: tachypnea, tachycardia, an enlarged heart, soft heart sounds that may have a tictoc rhythm, cardiac gallop cadence, and either no murmurs or systolic murmurs of mitral or tricuspid regurgitation or aortic or pulmonary stenosis/outflow tract obstruction. Alternatively, they may present chronically with failure to thrive, decreased exercise tolerance, and more subtle findings of heart failure. Occasionally, the predominant process may be an arrhythmia, either atrial or ventricular tachycardia/fibrillation, or bradycardia/heart block. These present clinically with palpitations, syncope, or sudden death.