This document contains information about hypertrophic obstructive cardiomyopathy (HOCM). It begins with an overview of HOCM, defining it as a genetic heart condition characterized by asymmetric left ventricular hypertrophy. It then discusses the pathophysiology of HOCM, focusing on left ventricular outflow tract obstruction, diastolic dysfunction, myocardial ischemia, and mitral regurgitation due to systolic anterior motion of the mitral valve. The document outlines clinical manifestations such as symptoms, physical exam findings, ECG and echocardiographic features, and complications. It concludes by covering treatment options for HOCM including medications, surgical septal myectomy via transaortic or transapical approaches, and other procedures like alcohol septal

1. Killer that claims four young lives each week
Daily Express - 31st August 2004
By Hilary Freeman
Parents call for action on sudden deaths - Jo Revill Health Editor
The Observer - 13th June 2004
Teenager collapses dancing with friends
Daily Mail - 17th May 2004
Unexpected tragedies
Cycling Weekly - 17th April 2004
Hypertrophic Obstructive Cardiomyopathy
Presenter- Dr. Jyotindra Singh

2. Functional Classification
Dilated (Congestive, DCM, IDC)
– Ventricular dilation, hypokinetic
left ventricle, and systolic
dysfunction
Hypertrophic (IHSS, HCM,
HOCM, ASH)
– Inappropriate myocardial
hypertrophy, with or without left
ventricular obstruction
Restrictive (Infiltrative)
– Abnormal ventricular filling with
diastolic dysfunction
Arrhthymogenic Right
Ventricular (ARVD)
– Fibroadipose replacement of
right ventricle

3. HOW DO WE DEFINE HOCM?
IDIOPATHIC HYPERTROPHIC
SUBAORTIC STENOSIS
A myocardial disease characterized by
Asymmetric hypertrophy of IVS &
ventricles (LV > RV)
Microscopic evidence of myocardial fiber
disarray & fibrosis
Variable dynamic obstruction that is
usually sub aortic & is associated with
abnormal SAM of AML
Prevalence of HCM in the general
population is about 1 in 500 (0.2%).
2

4. Historical Perspctive
HCM was initially described by Teare in 1958
Braunwald was the first to diagnose HCM clinically
Goodwin & colleagus- namd it HOCM
SAM was described by Fix in 1964
Brock (1957) & Cleland (1958) did Ist myotomy- myectomy
Dobell & scott
/ Lillehi & Levy-
Cooley & colleagues- RV approach
LA approach

5. Background
Genetic disorder
Autosomal dominant
Molecular basis
beta myosin heavy chain &
Myosin binding protein C
Myocardial Ca++ kinetics
Increase Ca++ intracellular 
hypertrophy and cellular
disarray
Leading cause of sudden
death in preadolescent
and adolescent

6. HOCM VARIANTS- Morphology
2

7. LV CAVITY
Sub aortic -Small size
Sigmoid shaped
Midventricular -Dumbbell
shaped – prone for LV
apical aneurysm.
Apical- Spade shaped
Advanced disease-LV
dilation

8. Mitral Valve
Dynamic morphology
Obstruction in LVOT
Positioned closer to
ventricular septum
Disproportionately elongated
& thickened Leaflets -AML
PML closes against the body
of elongated AML- junction of
Middle & free edge

9. Fate of RV- LA-Coronaries
RV
RVOTO d/t Distorted IVS shape
RVH
P HTN d/t long standing LVH
LA ----Dilated & thickened ----Reduced LV compliance / MR
Coronaries---Large / Prominent muscular bridging (Total systolic occlusion)
---Wall thickening & luminal narrowing of septal branches

10. Histopathology
Increased fibrous tissue
Increase muscle cell diameter
Increase in number of cell
layers
Abnormalities in orientation of
myofibrils.
Avg degree of disarray is 30%
( >5% is diagnostic of HOCM)

11. Pathophysiology
Involves 4 interrelated processes:
– LVOT
– Diastolic
dysfunction
– Myocardial
ischemia
– Mitral
regurgitation

12. Physiological consequences -LVOT
Elevated intraventricular pressures
Prolongation of ventricular relaxation
Increased myocardial wall stress
Increased oxygen demand
Decrease in forward cardiac output

13. DIASTOLIC DYSFUNCTION
Diastolic Dysfunction
- Due to prolongation of isovolumic relaxation
time
-  LV filling pressure
-  Ventricular volume
- Atrial contribution to ventricular filling ~ 75%
Poor Compliance
-  LVEDP for any LVEDV
- Subendocardial ischemia

14. Myocardial Ischemia
 Myocardial muscle mass
 Myocardial oxygen demand
( wall stress)
 Diastolic filling pressures
 Coronary capillary density
 Vasodilatory reserve
Abnormal intramural
coronary arteries
Small-Vessel Disease and the Morphologic Basis for Myocardial Ischemia in
 Systolic compression
of coronary arteries
HCM(A) Native heart of a patient with end-stage HCM who underwent
transplantation. Large areas of gross macroscopic scarring are evident
throughout the LV myocardium(white arrows). (B) Intramural coronary artery
in cross-section showing thickened intimal and medial layers of the vessel wall
associated with small luminal area. (C) Area of myocardium with numerous
abnormal intramural coronary arteries within a region of scarring, adjacent to
an area of normal myocardium.

15. MITRAL REGURGITATION/SAM
SAM: (Bernoulli effect)
dynamic pressure gradient
across LV outflow tract
midsystolic intraventricular
obstruction of the flow
SAM - Septal Contact
dynamic obstruction
increased by:
 afterload
 contractility

17. Mitral Regurgitation
SAM (Classical of HOCM)
At systole -PML closes against mid part of AML
(Not the free edge)
On AML venturi effect of high velocity of blood stream
(D/t rapid & early ventricular ejection)
Free edge hinges on rest of leaflet & angulates towards
aortic valve & contacts with IVS
LVOTO
MR
– Results from the systolic
anterior motion of the mitral
valve
– Usually mid / late systolic
– Jet is directed posteriorly
– Severity of MR directly
proportional to LV outflow
obstruction
Usually relieved after relief
of LVOTO.
– Results in symptoms of
dyspnea, orthopnea

18. Electrical disturbances
-
Paroxysmal supraventricular
arrhythmias (30-50%)
- result in shorter diastolic filling time;
patients have palpitations, shortness of
breath, syncope
-
-
Atrial fibrillation (15-20%)
- poorly tolerated – the time for diastolic filling
decreased
Non-sustained ventricular
tachycardia (25% )
- occurs during ambulatory monitoring
-
Sustained ventricular
tachycardia/ventricular fibrillation

19. SYMPTOMS
Dizziness:
 by
Exertion
Hypovolemia
Maneuver (rapid standing or
valsalva)
Medication (diuretics, NTG
and Vasodilator Meds)
Arrhythmia hypotension
decrease cerebral perfusion
Dyspnea:
– Most common symptom, 90%
–  Lt Ventricular Diastolic filling
pressure   PAP
Orthopnea and Paroxysmal
Nocturnal Dyspnea:
– Pulmonary venous congestion
– Early signs of CHF
19

20. SYMPTOMS
Angina:
– Common with no CAD
– Impaired diastolic relaxation +  MVO2
Sub-endocardial
ischemia
–  Capillary density leads to  flow to hypertrophic muscle
– Extramural compression of coronaries
–  Systolic ejection time leads to  diastolic interval for
coronaries perfusion
Syncope and pre-syncope:
–
–
–
–
Very common
 CO with exertion or arrhythmia
High risk of sudden death
Urgent work-up and aggressive treatment
20

21. SYMPTOMS
Palpitation:
– Ventricular Arrhythmia75%
– SVT 25%
– A- fib 5-10%
Sudden cardiac death
(SCD):
– 6 % in children
– Related to extreme
exertion
– MCC of SCD is arrhythmia
80 % ~ V-fib
21

22. PHYSICAL SIGNS
Double apical impulse:
– Forceful left atrial contraction
against non-compliant ventricle
S1: normal
S2: normal or paradoxical split
S3 gallop: decompensated Lt.
ventricle
S4: atrial systole against
hypertrophic ventricle
Jugular venous pulse:
prominent a- wave
Double carotid arterial pulse:
declines in mid systole as gradient
develop
22

23. MURMURS
Systolic Ejection Murmur:
Crescendo - Decrescendo
– Between apex and left
sternal border
– Radiate to suprasternal
notch
–  by
 Preload (volume loading)
 Afterload (vasopressor)
–  by
 Preload (nitrates, diuretic,
standing)
 Afterload (vasodilator)
23

24. MURMURS
Holosystolic Murmur of
MR:
– Retrograde ejection of
blood flow into low
pressure left atrium
– Best heard at apex and
axilla
– Pt. with SAM* and
significant LV outflow
gradients
Diastolic Decrescendo
Murmur of AR: 10% of Pt.
*
Murmur intensity increases
( reduced LV size ---- raises level of
obstruction)
--Reduced Preload – valsalva/
standing/ tachycardia
--Reduced after load -- nitro
vasodilators
--Raised contractility – Ionotropes,
exercise
Murmur intensity decreases
--Increased preload -- squatting,
hand grip
--Increased after load
--Reduced contractility – B
blockers, CCB
24

25. DIAGNOSTIC EVALUATION-ECG
LVH - increased precordial voltages and nonspecific ST segment and T-wave abnormalities.
Asymmetrical septal hypertrophy
produces deep, narrow (“dagger-like”) Q
waves
infarction Q waves are typically > 40 ms
duration while septal Q waves in HCM are < 40
ms.
Lateral Q waves are more common than
inferior Q waves in HCM.
compensatory left atrial hypertrophy, with
signs of left atrial enlargement (“P mitrale”) on
the ECG.
Atrial fibrillation and supraventricular
tachycardias are common.
Ventricular dysrhythmias (e.g. VT) also occur
and may be a cause of sudden death.

26. (A) Parasternal long-axis view depicting severe asymmetric septal hypertrophy and systolic anterior
:
mitral valve motion (arrowhead);
(B) M-mode across the mitral leaflets depicting prominent systolic anterior motion (thick arrows) of
the anterior mitral leaflet (SAM);
(C) M-mode tracing across the aortic valve demonstrating partial closure of aortic leaflets
Date of download:
(arrowheads); and (D) accentuationCopyright © The American Collegeleft ventricular outflow tract obstruction
of late-peaking dynamic of Cardiology.
3/28/2013
All rights reserved.
after the Valsalva maneuver.

27. CARDIAC CATH

28. Disease Progression
J Am Coll Cardiol. 2003;42(9):1693.

29. Sudden Cardiac Death
 Most frequent in young




adults <30-35 years
old
Primary VF/VT
Tend to die during or
just following vigorous
physical activity
Often is 1st clinical
manifestation of
disease
HCM is most common
cause of SCD among
young competitive
athletes
J Am Coll Cardiol. 2003;42(9):1693.

30. COMPLICATIONS
Complications
Atrial Fibrillation
Heart Failure
– Only 10-15% progress
to NYHA III-IV
– Prevalent in up to 30%
of older patients
– CO decreases by 40% if
AF present
Endocarditis
Autonomic Dysfunction
– 4-5% of HCM patients
– Usually mitral valve
affected
Embolisation
– 25% of HCM patients
– Associated with poor
prognosis

31. TREATMENT
Goals:
–  Ventricular
contractility
Myocardial
depression
–  Ventricular volume
Volume loading
–  Ventricular
compliance and outflow
tract dimensions
Medical therapy
Device therapy
Surgical
Alcohol septal ablation
Transplantation
–  Pressure gradient
across the LVOT
– Vasoconstriction
31

32. Medical Therapy in HOCM
Goals
Exercise-induced
gradient
Beta-blockers
Verapamil
Disopyramide
Oxygen-demand
Prolong Diastolic
Filling Period
If maximum dose fails
Pacing
Ablation
Myectomy

33. TREATMENT
How Beta blockers
work?
 Pressure gradient across LVOT
–  Inotropic state of left
ventricle.
–  Diastolic dysfunction
–  Lt. Ventricle
compliance
 HR
–  Myocardial oxygen
consumption
–  Myocardial ischemia
potential
CONTRAINDIACATION
Inotropic
Sympathomimetic
Nitrates
Except in patients with CAD
Digitalis
Except with uncontrolled Afib.
Diuretics
 Preload and ventricular
volume
 Outflow gradient
33

34. SURGICAL MANAGEMENT
Septal myectomy
Trans aortic / Left ventriculotomy
Extended septal myectomy
myectomy with Plication of Aml
Modified konno operation
Mitral valve replacement

35. Surgical septal myectomy
•In patients that remain symptomatic despite maximal
medical therapy with
•SAM
• Septum thickness more than 18 mm
• Resting gradient more than 50 mmHg
• Provoked gradient more than 50 mmHg
. Occurrence of AF
. High risk for sudden death
• Asymptomatic younger patients with
. Gradient > 100 mmHg
. High risk of sudden death

36. TRANS AORTIC APPROACH
Median sternotomy/ CPB estsblished
Transverse aortotomy/ stay sutures
Right aortic cusp –retracted anteriorly
Narrow ribbon retractor-placed in LVOT
1st -Incision below right coronary cusp &
parallel to LVOT
2nd parallel incision- as far leftward as
possible- careful about MV
Both incision deepened –toward LV apex
Two parallel vertical incision connected by
transverse incision.- rectangular piece of
septum has been excised.
Patients with left anterolateral free wall
hypertrophy- third incision below the
commissure between left and right coronary
cusp & directed towards base of
anterolateral papillary muscle.

37. TRANS AORTIC APPROACH

38. TRANS AORTIC APPROACH

39. TRANS AORTIC APPROACH
This picture demonstrates the hypertrophied septum protruding into the left ventricular outflow
tract. The leaflets of the aortic valve are pulled aside. Looking through the annulus, the anterior
leaflet of the mitral valve is noted inferiorly, the bulging septum superiorly.

40. TRANS AORTIC APPROACH
Opening of the outflow tract is much larger after the fibrious tissue has been removed, along with
muscle; that the chords of the anterior leaflet of the mitral valve are now visible

41. ADJUNCTS TO MYECTOMY-TEE
Location & thickness
Adequacy of myectomy
Correction of MR
Identifying complications
Gradient/SAM/MR
IF residual gradient > 10 to
15 mm hg- additional
muscle resection.

42. APICAL MYECTOMY
Apical HCM /Midventricular obstruction
Incision in the apex of the left ventricle lateral to
the LAD
Excision of the ventricular muscle at the apex
and midventricular level is performed.
Objective- increasing LV end diastolic volume /
Improve LV compliance
Post op – significant decrease in LV end
diastolic pressure ,increase in LV diastolic
volume index,increase in stroke volume.

43. Modified konno operation

44. Modified Konno Operation
Localized subaortic stenosis or tunnel stenosis-when
aortic annulus and valve are normal.
Transverse aortotomy.
RV opened –transverse incision- 2cm inferior to the
level of pulmonary valve cusp.
Right angle clamp –passed from aortotomy through
aortic valve –into left side of LVOT
Tip of the clamp palpated from septum-incision made
through RV sideIncision extended inferiorly about 1 cm parallel to
LVOT – at an angle to RVOT.
Patch used to widen- LVOT

45. Extended myectomy with reconstruction of
subvalvular apparatus -- Messmer
Septal myectomy extended into the LV cavity- wide
toward the apex
Providing access to both the papillary musclemobilized down to the apex
All hypertrophied portions and muscle trabeculae are
resected.
Mobilization of malpositioned papillary musclepermits mitral leaflets to deflect from LVOT during

46. Myectomy with plication of AML -- McIntosh
Plication can be
performed through the
aortic valve.
Horizontal/vertical
direction
Polypropylene sutures

47. ANTERIOR LEAFLET EXTENSION
Insertion of a pericardial patch.
Increases leaflet stiffness.
Causes lateral displacement of the secondary
chordae tendinae.
Functions haemodynamically as a spinnakar sail to
eliminate SAM.

48. MITRAL VALVE REPLACEMENT/REPAIR
Mitral valve replacement- Reserved for severely symptomatic individuals with
gradient > 50 mmHg in special situations like
Thin septum < 18 mm
Small aortic annulus
Unusual morphology of septum
Inability to achieve adequate resection
Not amenable to repair- Myxomatous/ degenerative.
Residual or recurrent obstruction
Annuloplasty rings should be avoided to prevent SAM
If necessary – flexible or rigid bands on the posterior leaflet preferred.

49. Postoperative care
Maintain adequate preload- LA pressure of 16 to 18
mm hg may be required
Avoid digitalis & isoproterenol – increase residual
outflow gradient
Avoid hypovolemia & NTG
AF is poorly tolerated - Use of amiodarone

50. Complications
Complete heart block (2.5% to 10 %) / LBBB (50%)
Perioperative MI
VSD (3%)
> if septal thickness < 18 mm
D/t iatrogenic / septal infarctionb
AR (5%)
Progressively increasing
Risk - Small aortic annulus (<21 mm),
Low mitral septal contact lesion
D/t iatrogenic/ loss of support to right cusp/ Hemodynamic
changes
LV aneurysm

51. Surgical Myectomy
Operative mortality
0.8%
Gradient reduction
67 ----3
Post-op NYHA 1-2
1.0
94%
Obstructive Post-myectomy
0.9
0.8
NYHA Pre
Post
I
2
24
III
48
7
IV
0.6
30
II
0.7
1
14
0
Obstructive
Operative mortality 0.8%
0.5
0
2
4
6
Ommen S et al. J Am Coll Cardiol 2005
8
10

52. Hospital mortality 0- 6%
5 yr survival
93-84%
10 yr survival 88-71 %

53. ALCOHOL Ablation
Alcohol SeptalSEPTAL ABLATION
-
performed percutaneously
- 100% alcohol is injected into a septal perforator
-
results in infarction of the injected area
 Successful short-term outcomes
 LVOT gradient reduced from a mean of 60-70 mmHg to <20 mmHg
 Symptomatic improvements, increased exercise tolerance
 Long-term data not available yet
 Complications
spill over
Complete heart block
Large myocardial infarctions
Ventricular arrhythmia & ECG changes

54. ALCOHOL SEPTAL Ablation
Alcohol Septal ABLATION
Before
After

55. DUAL CHAMBER PACING
Dual-Chamber Pacing
Proposed benefit: pacing the RV apex will
Decrease the outflow tract gradient
By – Decreased septal motion
Reduced SAM of the AML
Late activation of base of septum
Decreased LV contractility
used in patients with significant symptoms who would not tolerate
surgical therapy
Objective measures such as exercise capacity and oxygen consumption
are not improved
No correlation has been found between pacing and reduction of LVOT
gradient

56. OTHER MEASURES
Dual-Chamber Pacing
CARDIOVERTER – DEFIBRILLATOR
in combination with myectomy - pts. With history of cardiac arrest/
unexplained syncope.
CARDIAC TRANSPLANT
not responding to maximal medical/surgical theraphy
intractable heart failure with dilated ventricular cavities
LEFT VENTRICULAR- AORTIC CONDUIT
valved conduit from apex of LV to the thoracic or abdominal aorta

58. Ablation vs. Myectomy
279 patients
Procedural Mortality (%)
1.4
80
1.3
1.2
60
1
0.8
70
75
71
50
0.9
40
30
0.6
20
10
0.4
0
15
7
Myectomy
0.2
0
Myectomy
Ablation
Ablation

59. Efficacy of Therapeutic Strategies
Nishimura et al. NEJM. 2004. 350(13):1323.

60. HCM vs. Athletic Heart
HCM
Can be asymmetric
Wall thickness: > 15 mm
LA: > 40 mm
LVEDD : < 45 mm
Diastolic function: always abnormal
60 of 48
Athletic heart
Concentric & regresses
< 15 mm
< 40 mm
> 45 mm
Normal
Occurs in about 2% of elite althetes –
typical sports, rowing, cycling, canoeing
Former athletes & weekend warriors do
NOT develop athletic heart
Elite female athletes do NOT develop
athletic heart

61. X ray
Cardiomegaly
LA enlargement
Small aorta
Pulmonary edema