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Hypertrophic Obstructive Cardiomyopathy

Presenter- Dr. Jyotindra Singh

Functional ClassificationDilated (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

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

Historical PerspctiveHCM 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- LA approach

Cooley & colleagues- RV approach

Background

Genetic disorderÞ Autosomal dominant

Molecular basis Þ beta myosin heavy chain & Þ Myosin binding protein C

Myocardial Ca++ kineticsÞ Increase Ca++ intracellular

hypertrophy and cellular disarray

Leading cause of sudden death in preadolescent and adolescent

HOCM VARIANTS- Morphology

2

LV CAVITY

Sub aortic -Small sizeSigmoid

shaped

Midventricular -Dumbbell shaped – prone for LV

apical aneurysm.

Apical- Spade shaped

Advanced disease-LV dilation

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

Fate of RV- LA-CoronariesRV 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

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)

Pathophysiology Involves 4 interrelated processes:

–LVOT

–Diastolic dysfunction

–Myocardial

ischemia

–Mitral regurgitation

Physiological consequences -LVOTElevated intraventricular pressures

Prolongation of ventricular relaxation

Increased myocardial wall stress

Increased oxygen demand

Decrease in forward cardiac output

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

Myocardial Ischemia

Myocardial muscle mass

Myocardial oxygen demand

( wall stress)

Diastolic filling pressures

Coronary capillary density

Vasodilatory reserve

Abnormal intramural

coronary arteries

Systolic compression

of coronary arteries

 Small-Vessel Disease and the Morphologic Basis for Myocardial Ischemia in 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. 

MITRAL REGURGITATION/SAM

SAM: (Bernoulli effect)Þ dynamic pressure gradient

across LV outflow tract

Þ midsystolic intraventricular obstruction of the flow

SAM - Septal Contact dynamic obstruction

increased by:

afterload

contractility

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

Mitral Regurgitation

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

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

SYMPTOMS

20

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

SYMPTOMS

21

SYMPTOMSPalpitation:– 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

22

PHYSICAL SIGNSDouble 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

23

MURMURSSystolic 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)

24

MURMURSHolosystolic 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

DIAGNOSTIC EVALUATION-ECGLVH - increased precordial voltages and non-specific 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.

Date of download: 3/28/2013

Copyright © The American College of Cardiology. All rights reserved.

(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 (arrowheads); and (D) accentuation of late-peaking dynamic left ventricular outflow tract obstruction after the Valsalva maneuver.

:

CARDIAC CATH

Disease Progression

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

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.

Complications

Heart Failure

– Only 10-15% progress to NYHA III-IV

Endocarditis

– 4-5% of HCM patients

– Usually mitral valve affected

Embolisation

Atrial Fibrillation

– Prevalent in up to 30% of older patients

– CO decreases by 40% if AF present

Autonomic Dysfunction

– 25% of HCM patients – Associated with poor

prognosis

COMPLICATIONS

31

TREATMENTGoals: – Ventricular

contractility

Myocardial depression

– Ventricular volume

Volume loading

– Ventricular compliance and outflow tract dimensions

– Pressure gradient across the LVOT

– Vasoconstriction

Medical therapy

Device therapy

Surgical

Alcohol septal ablation

Transplantation

DisopyramideVerapamil

Beta-blockers

If maximum dose failsIf maximum dose fails

PacingAblation

Myectomy

PacingAblation

Myectomy

Medical Therapy in HOCM

Goals Exercise-induced

gradient

Oxygen-demand

Prolong Diastolic Filling Period

33

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

NitratesExcept in patients with CAD

Digitalis Except with uncontrolled A-fib.

Diuretics

Preload and ventricular volume

Outflow gradient

TREATMENT

Septal myectomy

Trans aortic / Left ventriculotomy

Extended septal myectomy

myectomy with Plication of Aml

Modified konno operation

Mitral valve replacement

SURGICAL MANAGEMENT

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

TRANS AORTIC APPROACHMedian 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.

TRANS AORTIC APPROACH

TRANS AORTIC APPROACH

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.

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

TRANS AORTIC APPROACH

Location & thickness

Adequacy of myectomy

Correction of MR

Identifying complications

Gradient/SAM/MR

IF residual gradient > 10 to 15 mm hg- additional muscle resection.

ADJUNCTS TO MYECTOMY-TEE

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.

Modified konno operation

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 side-

Incision extended inferiorly about 1 cm parallel to LVOT – at an angle to RVOT.

Patch used to widen- LVOT

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 muscle- mobilized down to the apex

All hypertrophied portions and muscle trabeculae are resected.

Mobilization of malpositioned papillary muscle- permits mitral leaflets to deflect from LVOT during systole

Myectomy with plication of AML -- McIntosh

Plication can be performed through the aortic valve.

Horizontal/vertical direction

Polypropylene sutures

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.

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.

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

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

0.5

0.6

0.7

0.8

0.9

1.0

0 2 4 6 8 10

Surgical Myectomy

I 1 30

II 2 24

III 48 7

IV 14 0

NYHA Pre Post

Obstructive

Obstructive Post-myectomy

Operative mortality 0.8%

Ommen S et al. J Am Coll Cardiol 2005

Operative mortality 0.8%

Gradient reduction 67 ----3

Post-op NYHA 1-2 94%

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

Alcohol Septal Ablation

- performed percutaneously

- 100% alcohol is injected into a septal perforator

- results in infarction of the injected area

Successful short-term outcomesLVOT 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 blockLarge myocardial infarctions

Ventricular arrhythmia & ECG changes

ALCOHOL SEPTAL ABLATION

Alcohol Septal Ablation

Before After

ALCOHOL SEPTAL ABLATION

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

DUAL CHAMBER PACING

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

OTHER MEASURES

Ablation vs. Myectomy

0.9

1.3

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Myectomy Ablation

279 patientsProcedural Mortality (%)

71

7

75

15

0

10

20

30

40

50

60

70

80

Myectomy Ablation

Efficacy of Therapeutic Strategies

Nishimura et al. NEJM. 2004. 350(13):1323.

60 of 48

HCM vs. Athletic HeartHCM

Can be asymmetric

Wall thickness: > 15 mm

LA: > 40 mm

LVEDD : < 45 mm

Diastolic function: always abnormal

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

X ray

Cardiomegaly

LA enlargement

Small aorta

Pulmonary edema