HYPERTROPHIC CARDIOMYOPATHY IN ECHO

DEFINITION:

Hypertrophied
Non-dilated left ventricle (LV)
Absence of another cardiac or systemic disease

HCM

Autosomal dominant with incomplete penetrance.
Most common inheritable cardiovascular disease (0.1-0.2% in general population).

HCM - PRESENTATION

36 year old gentleman presented to general/ CV clinic with a history of shortness of breath (usually with exertion).
Dizziness, presyncope/syncope, AF ?cause, family history of sudden death, atypical chest pain and heart failure symptoms.
Look at the ECG: LVH with strain, deep T wave inversion.

HCM - Differential

Noonan’s, LEOPARD, Friedrich ataxia
RV hypertrophy, D-TGA Athletes heart, hypertension, AS
Fabry’s, Glycogen storage disease, hypothyroidism, Mucopolysaccharidoses
Amyloidosis, Sarcoidosis

HCM
Echocardiography:

Determining the pathophysiology of HCM.
Quantitating its morphology and hemodynamic severity.
Assessing the acute, chronic responses to various therapies.
Provide assistance during therapeutic procedures.
Insight into the epidemiology, inheritance and prognosis.

HCM
Diagnosis:

Asymmetric septal hypertrophy (ASH)
Septal to posterior wall thickness ratio > 1.3 (1.5), septum that is typically at least 15mm.
In children, LV wall measurements are more than 2SD above the mean (corrected for age and body surface area).
*30mm - sudden death risk.

HCM – LVH, Severity, Distribution and Patterns

PLX, serial PSX.
10 point system
Maron classification.
Pitfalls: Focal hypertrophy especially apical regions with sub-optimal windows and beware of oblique cuts.

HCM

Maron I : isolated anterior septum (10%).
Maron II : pan-septal without free wall involvement (20%).
Maron III : septum and antero-lateral free wall (52%).
Maron IV : all other types of hypertrophy (18%).

HCM - LVOTO
M-mode evaluation:

Narrowing of the LVOT
Mid-systolic notching of the aortic valve (no relationship with severity).
SAM of the mitral valve

HCM -LVOTO
Factors contributing to LVOTO:

(A) Narrowing of the LVOT by
(1)septal hypertrophy
(2)anterior displacement of the mitral apparatus
(3)anterior displacement of the papillary muscle

(B) HydroDynamic forces
(Venturi and drag forces) due to rapid early LV ejection with elongated mitral leaflets.

HCM – LVOTO - SAM

Occurs with the onset of the pressure gradient. (significant relationship with the obstructive gradient).

M-mode echocardiographic classification of SAM:

(1)Mild: SAM septal distance >10mm
(2)Moderate: SAM septal distance <10mm>HCM - LVOTO
(3)Severe: prolonged SAM septal contact, lasting more than 30% of systole.

HCM-LVOTO

Colour-flow mapping.
PW doppler – always start from the apex
CW doppler – spectral profile with a leftward concave shape (dagger shape).
Gradient (4V2), inducible by exercise techniques.
*LVOTO to MR doppler profile. MR doppler profile is earlier in onset, abrupt initial increase in velocity and a higher peak velocity (>5.5m/s).
Gradient: 30mmHg

HCM - MR

Evaluate valve morphology.
Mid to late systole.
Typical posterior-directed jet, presence of non-posterior jet suggest intrinsic mitral valve abnormality.
Related to the degree of anterior leaflet SAM, to the length of the posterior leaflet and the degree of mid systolic coaptation of the leaflets.

HCM – DIASTOLIC FUNCTION

Diastolic function is impaired.
Impaired LV relaxation pattern.
Filling pressures: Colour M-mode and tissue doppler techniques (TDI).
Asynchronous relaxation: base to apex (intracavitary IVRT flow), in ASH – base to apex flow and in apical HCM, apex to base flow.

HCM - TDI

Reduced Ea (detect genotype positive without LVH).
E/Ea with VO2 max, FC and serious events.
Ea to monitor response to invasive therapies.

HCM - TDI
Tissue doppler

Sa (lateral) < 13cm/s 100% Sensitivity 93% Specificity Sa (septal) < 12cm/s 100% Sensitivity 90% Specificity Ea (lateral) < 14cm/s 100% Sensitivity 90% Specificity Ea (medial) < 13cm/s 100% Sensitivity 90% Specificity

HCM – Strain Imaging

Myocardial strain allows the assessment of regional myocardial function.
Differentiate HCM from hypertensive heart disease.
Systolic strain of < -10.6% (85% sensitive, 100% specific, accuracy of 91%). All components of systolic strain is reduced in HCM.

Thank you and good luck