• Hypertrophic cardiomyopathy
    • Genetic condition usually due to mutations in one of several sarcomere genes causing LVH and potentially LV outflow obstruction, diastolic dysfunction, mitral regurgitation. Patients may present with CP, dyspnea, palpitations, syncope, or SCD (from sustained ventricular arrhythmias).
    • EKG often shows LVH, but can also show abnormal Q waves or P wave abnormalities (LA or biatrial enlargement).
  • Coronary artery anomalies
    • Anomalous origin of one or more coronary arteries from pulmonary artery can produce myocardial ischemia that can progress to ischemic cardiomyopathy. Infants may present with irritability or in shock whereas older children and young adults may present with heart failure or SCD.
  • Myocarditis
    • Viral is the most common cause in children (enterovirus, adenovirus, EBV, CMV) but this condition can also be autoimmune, bacterial, or drug-related. EKG tends to be non-specific, with ST changes and T wave inversions, and sometimes decreased voltage.
  • Arrhythmogenic right ventricular cardiomyopathy
    • fibro-fatty replacement of myocardium causes scarring of RV, RV dilation, and arrhythmias (VT most commonly). Patients can be asymptomatic or present with dizziness, palpitations, syncope, chest pain or SCD.
    • EKG may have QRS prolongation, RBBB, prolonged S wave upstroke, epsilon wave, or T wave inversions V1-V3
  • Ion channelopathies (congenital long QT syndromes, Brugada syndrome, etc.)
    • LQTS most often due to loss of function mutation of a potassium channel gene or a gain of function mutation of a sodium channel gene. Most common syndromes include Romano-Ward and Jervell and Lange-Nielsen syndrome. High risk for torsades de pointes with possible syncope or SCD.
    • Brugada syndrome is caused by a loss of function mutation of a cardiac sodium channel gene. EKG findings of ST elevations in V1-V3 and pseudo-RBBB pattern in right precordial leads are typically seen.