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.