This document discusses the echocardiographic evaluation of hypertrophic obstructive cardiomyopathy (HCM). Key points include: - Echocardiography is used to diagnose HCM based on unexplained left ventricular hypertrophy and rule out other causes. Asymmetric septal hypertrophy is a characteristic pattern. - Doppler echocardiography is used to detect left ventricular outflow tract obstruction at rest and with provocative maneuvers like Valsalva. - Features like systolic anterior motion of the mitral valve indicate dynamic obstruction and need to be monitored with maneuvers. - Differential diagnosis includes secondary causes of left ventricular hypertrophy from things like hypertension which present differently on echocard

1. Echocardiographic evaluation of
Hypertropic obstructive
cardiomyopathy
Dr.S.R.Sruthi Meenaxshi MBBS, MD,
PDF

2. Left ventricular cavity dimensions

4. Hypertrophic cardiomyopathy
• Hypertrophic cardiomyopathy (HCM) is
characterized by increased left ventricular (LV)
mass, which is quantitated by determining the
wall thicknesses and estimating the LV wall
mass.
• When these findings are present without
apparent etiology, the cause of hypertrophy in
the majority of cases is mutation in a gene
encoding cardiac sarcomeric proteins.

5. • The echocardiographic diagnosis of HCM is based
upon the finding of an otherwise unexplained
hypertrophied, nondilated LV
• A septal wall thickness ≥15 mm has been
commonly used to diagnose HCM (both
ACC/AHA and ESC guidelines), although other
causes for hypertrophy must be excluded and
some patients with HCM do not meet this
threshold for septal thickness

6. • The degree and distribution of left ventricular
hypertrophy (LVH) in HCM are variable, and
include
• septal hypertrophy with or without obstruction to
LV outflow,
• concentric hypertrophy
• apical hypertrophy
• hypertrophy of the LV free wall
• right ventricular hypertrophy

8. • One characteristic pattern is asymmetric
septal hypertrophy (ASH) with wall thickness
greatest at the basal septum.
• ASH is recognized by a septal to posterior wall
ratio of 1.5 to 1.

9. • In a more unusual and often more clinically
benign variant of HCM, the apex is the site of
the greatest hypertrophy
• Apical hypertrophy is more difficult to identify
by echocardiography because the apical
myocardium is more difficult to image

11. • When this condition is suspected (eg, by finding
deeply inverted precordial T waves on ECG), it is
helpful to use an echocardiographic contrast
agent to confirm the diagnosis and identify the
small apical aneurysm that may form distal to the
obstruction
• Cardiac magnetic resonance imaging is a
preferred imaging test for
identification/exclusion of the apical
hypertrophic syndrome since it can detect apical
aneurysms missed by echocardiography.

12. Echocardiographic features
The echocardiogram with Doppler is the most
practical means to assess the hemodynamics of
HCM.
• Approximately 20 to 25 percent of patients have
a resting left ventricular outflow tract (LVOT)
gradient of greater than 30 mmHg
• However, when the obstruction is dynamic (ie,
provocable but mild or absent at rest), the task of
the echocardiographic laboratory is more difficult

14. Asymmetrical septal hypertrophy
e point septal contact

15. HOCM

19. DAGGER SHAPED FLOW DISTAL TO
HYPERTROPHIED SEPTUM

20. Systolic anterior motion of the mitral leaflet
causing left ventricular outflow tract obstruction
note the posteriorly directed MR jet

21. M mode through the aortic root at aortic level
shows midsystolic flutter or notch- lobster claw
abnormality
due to impact of dynamic subaortic obstruction
on the behaviour of aortic valve

22. Lobster claw abnormality

23. • Use of Doppler techniques, particularly
continuous wave, is mandatory.
• This modality is typically used to measure the
systolic flow velocity in the LVOT and mid cavity
at rest and during maneuvers (eg, Valsalva;
normal 0.9 m/second)
• Doppler in this setting will also enable the
recognition of dynamic mitral regurgitation that
often appears with a posteriorly directed jet in
concert with outflow tract obstruction.

24. Patients with LVOT obstruction often
have the following features:
Asymmetric septal hypertrophy
Systolic anterior motion of the mitral valve (SAM)
Crowding of the mitral apparatus by the LVOT
Partial early systolic closure or notching of the aortic
valve
Calcification of the mitral annulus frequently
accompanies HCM, and, in some patients, this finding
is the only clue to the potential for dynamic outflow
tract obstruction
Mitral regurgitation often accompanies obstruction
and the mitral regurgitation jet needs to be
distinguished from the gradient jet.

25. Significant hypertropy of the
interventricular septum

30. Strain echocardiography
• Strain is measured by speckled-tracking measures of both
global and regional ventricular function, and can detect
reduced myocardial function in HCM
• It also correlates with myocardial fibrosis and predicts
ventricular arrhythmias
• In addition, mechanical dispersion (defined as the standard
deviation of time from the onset of the QRS to peak
negative strain) was significantly increased in HCM patients
and was both related to amount of fibrosis and was an
independent predictor of arrhythmia
• In athletes, mechanical dispersion of longitudinal strain
may be superior to global longitudinal strain (GLS) in
identifying HCM

31. • Patients with HCM have significantly lower
longitudinal systolic strain, systolic strain rate, and
early diastolic strain rate as compared with concentric
hypertrophy due to systemic hypertension
• Recognition of HCM may be facilitated by recording of
strain data in a polar map, which have different
patterns among different types of cardiomyopathy
• GLS is independently associated with outcomes in
HCM patients, with GLS greater than -10 percent
associated with higher risk of adverse events

32. Provocative maneuvers
• Whenever obstructive or nonobstructive
HCM is suspected but not overt, it is often
desirable to perform some sort of intervention
or provocation during the echocardiographic
examination; the most frequently used
maneuver is the Valsalva maneuver and the
most common pharmacologic intervention is
amyl nitrate inhalation

35. • Use of Doppler techniques, particularly
continuous wave, is mandatory.
• This modality is typically used to measure the
systolic flow velocity in the LVOT and mid cavity
at rest and during maneuvers (normal 0.9
m/second)
• Doppler in this setting will also enable the
recognition of dynamic mitral regurgitation that
often appears in concert with outflow tract
obstruction.

36. • Systolic anterior movement of the mitral valve
(SAM) on 2D and M-mode imaging provides
independent evidence of dynamic obstruction
• if there is also contact of the mitral leaflet tip
and the septum;
• the more severe the obstruction, the more
prolonged the contact

37. • If obstruction worsens with provocation, SAM will also worsen. SAM is
graded as follows:
●0 = absent.
●1+ = present, with a minimum distance between the mitral valve and
ventricular septum during systole >10 mm.
●2+ = without mitral-septal contact, but with a distance of <10 mm between
the mitral valve and septum.
●3+ = brief mitral-septal contact (<30 percent of echocardiographic systole).
●4+ = prolonged apposition of the mitral valve leaflet with the septum (>30
percent of echocardiographic systole).
●Inspection of the aortic valve at the peak of provocation will provide
secondary evidence of obstruction by demonstrating early systolic closure
(producing notching, also known as a peak and dome configuration on M-
mode echocardiography)

39. • A Valsalva maneuver is usually performed first, and if it fails to
provoke changes, amyl nitrite inhalation may sometimes be used.
• During this more vigorous provocation the same structures are
monitored. It is ideal during any intervention to have someone
performing auscultation.
• If technical problems interfere with echocardiography or Doppler,
detection of a new or worsening murmur, particularly if intense,
may be sufficient to identify a culprit condition.
• Exercise testing may also be used to evaluate this condition.
• We use supine bicycle so that it is possible to image the heart and
sample flow by Doppler during and after the stress test.
• In this way changes in gradient, severity of mitral regurgitation, and
rhythm may be sought. Note that the dynamic outflow gradient
often does not worsen until the immediate post-exercise period.
This behavior of dynamic obstruction often mimics a common
symptom complex in HCM

40. Differential diagnosis
• The differential diagnosis of familial HCM includes LVH
secondary to other disorders as well as other causes of
HCM morphology such as amyloidosis
• LVH is considered secondary when due to an
identifiable disorder such as hypertension or aortic
stenosis.
• As noted above, these disorders are not classified as
cardiomyopathies.
• Secondary LVH is most commonly encountered as a
complication of hypertension. The presence of LVH in a
hypertensive subject increases the likelihood of
cardiovascular morbidity and mortality

42. Echocardiographic features of
secondary left ventricular
hypertrophy
• Echocardiography is the procedure of choice
for identifying secondary LVH since the
sensitivity of the various electrocardiographic
(ECG) criteria may be as low as 7 to 35 percent
with mild LVH and only 10 to 50 percent with
moderate to severe disease

43. • The hypertrophy is usually asymmetric in
inherited HCM, and symmetric in secondary
disease
• The predictive accuracy of the pattern of
hypertrophy for genetically determined versus
secondary hypertrophy, however, is low.

46. Sigmoid septum
• Focal apparent hypertrophy of the basal interventricular
septum (known as sigmoid septum or angulated septum)
occurs commonly in older adults, seemingly as the result of
an age-related shift in the orientation of the LV long axis
from vertical to horizontal.
• Contrast imaging of the LV suggests that there is little, if
any, hypertrophy.
• As a rule, if the LV wall is not thickened and LV volume is
normal, an elevated calculated LV mass in a patient with
sigmoid septum is likely artifactual.