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HCM Presentation, Hemodynamics and InterventionBy: Dr. Ankur GuptaResident, Dept. of CardiologyDhiraj Hospital.

HistoryA 50 year old female presented with Breathlessness on extertion (NYHA Class II) Angina on exertion (Class II) 8 monthsRepeated episodes of presyncope Symptoms aggravated for past one month.

On examination Systolic ejection murmur in lower left sternal border and apex.

ECG:Normal, sinus rhythm. Normal axis.ST segment depression in Leads V5, V6, I, aVL.

Differential diagnosisAortic stenosisHypertrophic obstructive cardiomyopathy

EchocardiographyAsymmetric septal hypertrophy (ASH) IVS: 19 mm, PW 12 mm.

Systolic anterior motion (SAM) of mitral leaflet.

Peak gradient of 90 mm Hg across left ventricle outflow tract (LVOT) suggestive of hypertrophic obstructive cardiomyopathy (HOCM).

Moderate MR.

Asymmetric septal hypertrophy (ASH) with systolic anterior motion (SAM) of mitral leaflet.

Cardiac catheterization and Alcohol Septal Ablation

DiscussionHypertrophic cardiomyopathy

DefinitionCharacterized by a thickened but nondilated left ventricle in the absence of another cardiac or systemic condition (e.g., aortic valve stenosis, systemic hypertension, some expressions of physiologic athletes heart) capable of producing the magnitude of LV hypertrophy evident in this disorder.

BackgroundGenetic disorder Autosomal dominant.

Molecular basis Defect in sarcomeric protein genes.

Abnormal myocardial Ca++ kinetics Increase Ca++ intracellular hypertrophy and cellular disarray

Leading cause of sudden death in preadolescents and adolescents.

Some facts regarding HCM

Sex: Male = female.

Age: Most common in 30s - 40sMost common autopsy finding in previously healthy athletes

Frequency: 1 in 500 people25 % of first degree relative

70% of patients have obstructive form of HCM.

Variants of HCMMost common location: subaortic, septal and anterior wall.

Asymmetric hypertrophy (septum and anterior wall): 70 %.

Basal septal hypertrophy: 15- 20 %.

Concentric LVH: 8-10 %.

Apical or lateral wall: < 2 % (25 % in Japan/Asia): characteristic giant T-wave inversion laterally & spade-like left ventricular cavity: more benign.

Pathophysiology of HCMHypertrophy: in any region of left ventricle.

SAM: systolic anterior motion of anterior MV leaflet against hypertrophic septum (Bernoulli effect) DRAG EFFECT. dynamic pressure gradient across LV outflow tract midsystolic intraventricular obstruction of the flow

SAM - Septal Contact dynamic obstruction, increased by: afterload preload contractility

Venturi effect: anterior mitral valve leaflets & chordae sucked into outflow tract obstruction, eccentric jet of MR in mid-late systole.

Arrhythmias

Diastolic DysfunctionDue to prolongation of isovolumic relaxation time (AV closure to MV opening) LV filling pressure Ventricular volumeAtrial contribution to ventricular filling ~ 75%

Poor Compliance LVEDP for any LVEDV Subendocardial ischemia

HCM

Hypertophic cardiomyopathy (HCM)Histologic FindingsGross disorganization of the muscle bundles and myofibrillar disarray

Morbidity / Mortality

Mortality rate ~ 1% per year.

Sudden death: younger patient, aggressive genotype ( < 30-35 yrs. old)

Arrhythmia: A- fib., A- flutter, V-tach. or V-fib.

CHF: MR and diastolic dysfunction

Angina: adults > children

Syncope and pre-syncope

Symptoms

SymptomsDizziness: increased by ExertionHypovolemia Maneuver (rapid standing or valsalva) Medication (diuretics, NTG and Vasodilators)Arrhythmia hypotension decrease cerebral perfusion

Dyspnea: Most common symptom, 90% Lt Ventricular Diastolic filling pressure PAP

Angina:Common with no CADImpaired diastolic relaxation + MVO2 Sub-endocardial ischemia Capillary density leads to flow to hypertrophic muscleExtramural compression of coronaries Systolic ejection time leads to diastolic interval for coronaries perfusion

Orthopnea and Paroxysmal Nocturnal Dyspnea:Pulmonary venous congestionEarly signs of CHF

Syncope and pre-syncope:Very common CO with exertion or arrhythmiaHigh risk of sudden deathUrgent work-up and aggressive treatment

Palpitation:Ventricular Arrhythmia75%SVT25%A- fib5-10%

Sudden cardiac death (SCD): 6 % in children Related to extreme exertion MCC of SCD is arrhythmia - 80 % ~ V-fib

Causes of Ischemia in HCM 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

Physical ExaminationMedium-pitch systolic ejection murmur at lower left sternal border and apex.Varies in intensity with the magnitude of sub-aortic gradients.Increases with Valsalva maneuver, during or immediately after exercise or on standing.

Systolic Ejection Murmur:

Decreases by Preload(volume loading) Afterload(vasopressor)

Increases by Preload(nitrates, diuretic, standing) Afterload(vasodilator)

Grade 3/6 murmur ~ LVOT gradient > 30 mm Hg.

Such variability, together with lack of radiation of the murmur to the neck, aids in differentiating dynamic subaortic obstruction from fixed aortic stenosis.

Double apical impulse:Forceful left atrial contraction against non-compliant ventricle

Arterial pulses Rapid rise with bisferiens contour.

Jugular venous pulse: prominent a- wave

Diagnosis ECGAbnormal in > 90% HCM patients and ~ 75% of asymptomatic relatives.

ST-T wave abnormalities (lateral precordial leads).

LV hypertrophy

Deep and narrow Q waves.

Diminished R waves in lateral precordial leads.LA enlargement

Axis deviation (left > right)

Conduction abnormalities (P-R prolongation, BBB)

A-fib (poor prognostic sign)

Diagnosis Echocardiography and Doppler MR and Mitral valve prolapse

Flow velocity: > 4.0 m/s

LV outflow gradient: > 50 mm Hg

EF : high to normal

Small LV cavity

Left atrial enlargement

Septal thickness: 4-6 mm thicker than normal (> 15 mm)

The hallmarks: SAM of Mitral valve Asymmetric septal hypertrophy

Diagnosis Cardiac catheterizationCardiac catheterization:Degree of outflow obstruction Diastolic characteristics of the left ventricle LV anatomyCoronary arteries anatomy

BrockenbroughBraunwaldMorrow signObserved in individuals with HCM with outflow tract gradient.

Differentiate HCM from aortic stenosis. (AS)

AS: after a premature ventricular contraction (PVC), the following ventricular contraction will be more forceful, and the pressure generated in the LV will be higher. Because of the fixed obstruction that the stenotic aortic valve represents, the post-PVC ascending aortic pressure will increase as well.

HCM: degree of obstruction will increase more than the force of contraction will increase in the post-PVC beat. LV pressure increases and the ascending aortic pressure decreases, with an increase in the LVOT gradient.

While the BrockenbroughBraunwaldMorrow sign is most dramatically demonstrated using simultaneous intra-cardiac and intra-aortic catheters, it can be seen on routine physical examination as a decrease in the pulse pressure in the post-PVC beat in individuals with HCM.

Left ventricular and aortic pressures simultaneously measured at rest on a 0 to 200 mm Hg scale show no evidence of a LVOT gradient.Classical image of the Brockenbrough-Braunwald- Morrow sign. Note the presence of a gradient of 150 mm Hg between the LV and Ao on the beat post-PVC

PVCLVAOBrockenbrough-Braunwald- Morrow sign: demonstrating the presence of LVOT obstruction with the distinct spike and dome waveform pattern

Pressure tracings demonstrating the BrockenbroughBraunwaldMorrow signAfter ASA, the Brockenbrough-Braunwald- Morrow sign is no longer present.

42

Left-Side Cardiac PressuresAortic upstroke rates - Delayed

supravalvular AS

valvular AS

subvalvular AS

Rapid and parallel to the LV pressureHOCM

Radionuclide study:Absence of CADDefects of myocardial perfusion

Holter monitoring:Non-sustained atrial or ventricular arrhythmia / 24 h

44TREATMENTGoals: Ventricular contractilityMyocardial depression Ventricular volumeVolume loading Ventricular compliance and outflow tract dimensions Pressure gradient across the LVOT Vasoconstriction

45Activity: Avoid Competitive level sports when:Significant outflow gradientSignificant arrhythmiaMarked LV hypertrophyHistory of sudden death in relatives Identified malignant genotype

46Pharmacologic therapy Inotropic state of left ventricle pressure gradient Compliance of the Left Ventricle Diastolic dysfunction

47MedicationsBeta-Blockers: (Metoprolol, Propranolol, Atenolol)

Calcium Channel blockers: (Verapamil, Diltiazem)

Antiarrhythmic: Amiodarone

Antitussives: avoid coughing

Beta - blockers Pressure gradient across LVOT Inotropic state of left ventricle. Diastolic dysfunction Left Ventricle compliance

HR Myocardial oxygen consumption Myocardial ischemia potential

49HCM - ContraindicationsInotropics

Sympathomimetics

NitratesExcept in patients with CAD

Digitalis Except with uncontrolled A-fib.

Diuretics Preload and ventricular volume Outflow gradient

50ManagementCatheter septal ablation96% ethanol infusion of Septal branch to destroy myocardial tissue.

The most appropriate candidates for Catheter septal ablation should meet all of the following criteria : -HCM with severe symptoms of heart failure (NYHA class III to IV) despite adequate tolerated drug therapy

-An LVOT gradient 50 mmHg at rest or after exercise or >30 mmHg at rest or 60 mmHg under stress

- Basal septal thickness 18 mm

- NYHA class II heart failure with a resting LVOTgradient >50 mmHg or >30 mmHg at rest and 100 mmHg with stress .

- Elderly or co-morbidities that may increase the risk of surgical correction.

Left ventricular myomectomy or septal myotomy:Indications:severe symptoms refractory to medical therapyoutflow gradient ~ >50 mm HgVerapamil (improve diastolic) and myomectomy (improve systolic)2% mortality overall

Mitral Valve Replacement

53Hypertrophic cardiomyopathy

54Implantable Cardioverter Defibrillator (ICD)Family h/o sudden deathUnexplained syncopeMassive LVH ( 30 mm)Hypotensive or attenuated blood pressure response to exerciseMultiple, repetitive nonsustained bursts of V-tach on serial ambulatory ECGs. Prevents sudden deathMany prospective studiesIn adults with CAD and EF, the ICD has been demonstrated to be superior to antiarrhythmic drug therapy

Take home message

Hypertrophic cardiomyopathy is a relatively common genetic disorder and usually asymptomatic.

~ 25% of patients develop LVOT obstruction and can develop angina, syncope, or CHF.

Beta-blockers: Symptomatic improvement.

Medically refractory patients: alcohol septal ablation or surgical myectomy.

Although surgical myectomy has been the gold standard, ASA has been shown in nonrandomized studies and a meta-analysis to be comparable.

Thank you