Exercise Testing in Hypertrophic Cardiomyopathy

Rowin EJ, Maron BJ, Olivotto I, Maron MS.
Role of Exercise Testing in Hypertrophic Cardiomyopathy. JACC Cardiovasc Imaging 2017;10:1374-1386.

The following are key points to remember from this article on the role of exercise testing in hypertrophic cardiomyopathy (HCM):

  1. Previously underutilized in HCM, exercise (stress) echocardiography has become incorporated into the standard clinical assessment and diagnostic armamentarium of HCM using upright or supine symptom-limited treadmill or bicycle modalities.
  2. Exercise testing provides critical information regarding mechanisms of functional limitation in HCM patients, as well as natural history and treatment options by replicating the type of activities in which patients engage on a daily basis.
  3. However, with respect to assessing myocardial ischemia, exercise testing in HCM is associated with substantial false-positive rates due to the high prevalence of pre-existing electrocardiogram abnormalities at baseline typical of this disease.
  4. The value of exercise echocardiography in assessing asymptomatic family members genotyped to pathogenic sarcomere mutations, but without left ventricular (LV) hypertrophy (genotype positive/phenotype negative), is limited given the low likelihood of provoking gradients due to systolic anterior motion in the absence of basal septal hypertrophy.
  5. LV outflow obstruction developing rapidly at lower levels of exercise is associated with greater impairment in functional capacity and New York Heart Association functional class compared with later onset of the gradient.
  6. In patients without outflow gradients at rest, exercise echocardiography is the most appropriate method for provoking obstruction, with the capability of predicting future development of progressive heart failure symptoms, and differentiating patients with provocable obstruction from those without obstruction, with major implications for dictating treatment options, that is, surgical myectomy (alternatively, alcohol septal ablation) versus heart transplant.
  7. Reduced myocardial oxygen consumption with metabolic (cardiopulmonary) exercise testing provides an independent and quantitative assessment of functional limitation for individual patients when the personal history is ambiguous, and also guides eligibility for heart transplant.
  8. Hypotensive blood pressure response to exercise can be an arbitrator in risk stratification decisions in HCM.
  9. Exercise testing with a variety of methods has become an integral and powerful component of the noninvasive evaluation of HCM, and in some patients can determine treatment strategy.
  10. Overall data support the expansive use of exercise testing in HCM to clarify prognosis and management options, and is particularly relevant in the current contemporary treatment era for this complex genetic disease.

Keywords: Bicycling, Blood Pressure, Cardiomyopathy, Hypertrophic, Diagnostic Imaging, Echocardiography, Echocardiography, Stress, Electrocardiography, Exercise Test, Genotype, Heart Failure, Heart Transplantation, Hypertrophy, Mutation, Myocardial Ischemia, Oxygen Consumption, Phenotype, Sarcomeres, Ventricular Outflow Obstruction

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