Hypertrophic Cardiomyopathy

objectives

  • The classic presentation of hypertrophic cardiomyopathy
  • Stress testing in hypertrophic cardiomyopathy
  • MPI findings of hypertrophic cardiomyopathy

Title Text

Stress testing: exercise

  • Abnormal ECGs are common
  • Abnormal ECG changes to exercise are common
  • ECG changes in HCM are not helpful in determining underlying CAD
  • Purpose:
    • Functional capacity
    • Provocation of LV outflow tract (LVOT) obstruction
    • Prognostic implications

LV hypertrophy - with strain

LV hypertrophy - without strain

Apical HCM

ECG changes with stress - normal MPI

CPET 

  • ECG changes of limited use
  • The benefit is measurement of anaerobic threshold, expiratory ventilation, carbon dioxide output, ratio of ventilation to carbon dioxide production

Stress echo

  • Limitations:
    • at rest regions of hypertrophy have abnormal wall motion. Nearly 75% of patients with HCM can develop LVOT obstruction during exercise
    • use of dobutamine as stress agent is not recommended because it can lead to significant LVOT gradient (in even normal individuals)
      • Leads to new wall motion abnormalities that do not correspond to coraronary artery disease

MPI

  • Nuclear scintigraphic MPI: relies on differential between rest and stress, SPECT hypoperfusion during stress, PET: absolute hypoperfusion
  • Measurement of absolute myocardial perfusion allows calculation of coronary flow reserve
  • High false positive on single-photon emission CT MPI
    • rest-stress related perfusion mismatch is due to microvascular ischemia
  • Areas of hypertrophy = hyperintense, lead other areas to appear hypoperfused

MPI

  • Septal stress perfusion defects resolve on repeat imaging post septal myomectomy: due to reduction in microvascular ischemia
  • MPI is best used as a negative predictor of epicardial CAD

uptake increase with hcm

Tower-Rader, A.,et al. Journal of the American Society of Echocardiography, 30(9), pp.829-844.

uptake increase with hcm

Tower-Rader, A.,et al. Journal of the American Society of Echocardiography, 30(9), pp.829-844.

deck

By Seana Nelson

deck

  • 60

More from Seana Nelson