Guideline sources The following summarized guidelines for the evaluation and management of hypertrophic cardiomyopathy are prepared by our editorial team based on guidelines from the European Society of Cardiology (ESC 2022; 2018; 2014), the American Heart Association (AHA/ACC 2020), and the American Heart Association (AHA/HRS/ACC 2019; 2018). 1 2 3 4 5 6 7 7 7 8 9 Definition Hypertrophic cardiomyopathy is a genetic disorder characterized by LV hypertrophy and a non- dilated left ventricle with preserved or increased ejection fraction. 7 Epidemiology Hypertrophic cardiomyopathy is most frequently caused by genetic mutations in genes ( -myosin heavy chain [MYH7] and myosin binding protein C [MYBPC3]) encoding sarcomere proteins. LV hypertrophy leads to diastolic dysfunction, reduced systolic output volume, decreased peripheral https://web.pathway.md/diseases/recp2rCpGQe4lzw9C 1/4 6/24/23, 12:45 PM Hypertrophic cardiomyopathy Pathway and myocardial perfusion, cardiac arrhythmia and/or HF and finally increased risk of sudden cardiac death. 7 Pathophysiology The prevalence of hypertrophic cardiomyopathy in the United States is low, with an estimated 200 cases per 100,000 population. HCM incidence is bimodal (peak incidence in the second decade and third decade of life). 8 Disease course Clinical manifestations include symptoms due to increased LV end-diastolic pressure (exertional dyspnea, exercise intolerance, orthopnea, peripheral edema, and HFpEF), LV outflow obstruction (exertional or immediately post-exertional syncope, ventricular arrhythmia), chest pain, palpitations, VT. Disease progression may lead to AF, hypertension, valvular disease, HF, and sudden cardiac death. 7 Prognosis and risk of recurrence Hypertrophic cardiomyopathy is associated with an annual mortality rate of 0.5%, and mortality is higher in children. However, sudden cardiac death is often the first clinical manifestation. 9 Calculator Calculator Calculator CHA DS VASc score for stroke CHADS score for stroke risk in a NYHA fun Guidelines 1. Screening and diagnosis Screening of family relatives, clinical and genetic testing: As per ACC/AHA 2020 guidelines, obtain a 12-lead ECG as part of screening in first-degree relatives of patients with hypertrophic cardiomyopathy. Obtain a TTE as part of the initial family screening and periodic follow-up in first-degree relatives of patients with hypertrophic cardiomyopathy. B Show 3 more As per HRS/ACC/AHA 2018 guidelines: Obtain an ECG and echocardiography in first-degree relatives of patients with hypertrophic cardiomyopathy. B Provide genetic counseling and obtain mutation-specific genetic testing in first-degree relatives of patients with hypertrophic cardiomyopathy due to a known causative mutation. B https://web.pathway.md/diseases/recp2rCpGQe4lzw9C 2/4 6/24/23, 12:45 PM Hypertrophic cardiomyopathy Pathway As per ESC 2014 guidelines, obtain cascade genetic screening, after pretest counseling, in first- degree adult relatives of patients with a definite disease-causing mutation. B Show 4 more Screening of family relatives, follow-up: As per ACC/AHA 2020 guidelines, do not obtain ongoing clinical screening in genotype-negative relatives in families with genotype-positive hypertrophic cardiomyopathy unless the disease- causing variant is downgraded to a variant of uncertain significance, likely benign, or benign variant during follow-up. D As per ESC 2014 guidelines, obtain clinical evaluation with ECG and echocardiography and long-term follow-up in first-degree relatives harboring the same definite disease-causing mutation as the proband. B Show 2 more Screening of family relatives, counseling: As per ACC/AHA 2020 guidelines, offer preconception and prenatal reproductive and genetic counseling in affected families with hypertrophic cardiomyopathy. B As per ESC 2014 guidelines, consider allowing sports activity in definite mutation carriers with no evidence of disease expression after taking into account the underlying mutation, the type of sports activity, and the results of regular and repeated cardiac examinations. C 2. Classification and risk stratification SCD risk assessment: As per ESC 2022 guidelines, assess the 5-year risk of sudden cardiac death at first evaluation and at 1-3-year intervals, or when there is a change in clinical status. B As per AHA 2018 guidelines, assess the sudden cardiac death risk at the time of initial evaluation and periodically thereafter in patients with hypertrophic cardiomyopathy. B As per ESC 2014 guidelines, use the HCM Risk-SCD score to estimate the risk of sudden death at 5 years in patients with hypertrophic cardiomyopathy aged 16 years, in the absence of a history of resuscitated VT/VF or spontaneous sustained VT causing syncope or hemodynamic compromise. B 3. Diagnostic investigations History and physical examination: elicit a complete medical and three-generation family history and perform a comprehensive physical examination as part of the initial diagnostic assessment in patients with suspected hypertrophic cardiomyopathy. B Show 2 more Electrocardiogram: As per AHA 2020 guidelines, obtain a 12-lead ECG as part of the initial evaluation of patients with hypertrophic cardiomyopathy. B https://web.pathway.md/diseases/recp2rCpGQe4lzw9C 3/4 6/24/23, 12:45 PM Hypertrophic cardiomyopathy Pathway As per ESC 2014 guidelines, obtain standard 12-lead ECG to aid diagnosis and provide clues to underlying etiology in patients with suspected hypertrophic cardiomyopathy. B Ambulatory ECG monitoring: As per AHA 2020 guidelines, obtain 24-48 hour ambulatory ECG monitoring during the initial evaluation to identify patients at risk for sudden cardiac death and to guide the management of arrhythmias. B Show 3 more As per AHA 2019 guidelines, consider obtaining prolonged ambulatory ECG monitoring in patients undergoing alcohol septal ablation and being at risk for developing late AV block. C As per ESC 2014 guidelines: Obtain 48-hour ambulatory ECG monitoring to detect atrial and ventricular arrhythmia in patients with newly diagnosed hypertrophic cardiomyopathy. B Obtain 48-hour ambulatory ECG monitoring in patients with frequent or sustained palpitations. B Implantable loop recorder: Consider placing an implantable loop recorder in patients with recurrent episodes of unexplained syncope at low risk of sudden cardiac death. C Consider placing an implantable loop recorder in patients with frequent palpitations with no identified cause after prolonged ECG monitoring. C Transthoracic echocardiogram: As per AHA 2020 guidelines, obtain a TTE in the initial evaluation of patients with suspected hypertrophic cardiomyopathy. B Show 4 more As per ESC 2014 guidelines, obtain a TTE (2D and Doppler) in all patients with hypertrophic cardiomyopathy at initial evaluation. B Show 5 more Transesophageal echocardiogram: As per AHA 2020 guidelines: Obtain an intraoperative TEE to assess mitral valve anatomy and function and adequacy of septal myectomy in patients with hypertrophic cardiomyopathy undergoing surgical septal myectomy. B Consider obtaining a TEE in patients with hypertrophic cardiomyopathy when the TTE is inconclusive in clinical decision-making regarding medical therapy, or for planning myectomy, excluding subaortic membrane or MR secondary to structural abnormalities of the mitral valve apparatus, or assessing the feasibility of alcohol septal ablation. C As per ESC 2014 guidelines: Obtain a TEE in patients undergoing septal myectomy, in order to confirm the mechanism of LV outflow tract obstruction, guide the surgical strategy, assess post-surgical complications, and detect residual LV outflow tract obstruction. B https://web.pathway.md/diseases/recp2rCpGQe4lzw9C 4/4