Luc A. Piérard , CHU Liège

Cardiomyopathie hypertrophique obstructive

Echocardiographie

Pronostic CMH

Bénigne et Stable

MortSubite

FA Progressiondes symptômes

Ins. cardiaque

STRATIFICATION DU RISQUE

GENETIQUEHistoire familiale de mort subiteMutations spécifiques

CLINIQUEArrêt cardiaque réaniméTV soutenue (>30 s) spontanéeSyncopes récidivantesTV au Holter

MORPHOLOGIQUE HVG sévère ( > 3 CM)

HEMODYNAMIQUE Gradient chambre de chasse( > 30 mm Hg)

Chute de PA à l’effort Réserve coronaire réduite

ECHOCARDIOGRAMME

- Hypertrophie septale asymétrique

- Distribution variable

- Parfois hypertrophie exclusivement apicale

- Mouvement systolique antérieur de la valve mitrale (SAM)

- Fermeture précoce de la valve aortique

ECHO DOPPLER

Formes obstructives

- Accélération du flux dans la chambre de chasse

- Maximum télésystolique : aspect en « lame de sabre »

- Gradient = 4 V2

- Régurgitation mitrale associée

- Variations du gradient en cas de pré- et post-charge (nitré)

Fonction diastolique

Etude du remplissage VG et Doppler tissulaire

. Trouble de relaxation

vs

. compliance

Maron et al NEJM 2003;348:295-303

HCM- RELATED DEATHVARIABLE

RELATIVE RISK p VALUE(95 % CI)

LV OUTLOW OBSTRUCTION ( > 30 mm Hg) 1.6 (1.1 - 2.4) 0.02

NYHA CLASS II, III, OR IV AT ENTRY 1.9 (1.2 - 2.9) 0.002

PAROXYSMAL OR CHRONIC ATRIAL AF 1.6 (1.1 - 2.4) 0.01

MAXIMAL LV THICKNESS > 30 mm 1.8 (1.1 - 2.8) 0.01

FEMALE SEX - 0.29

Maron et al NEJM 2003;348:295-303

Maron et al NEJM 2003;348:295-303

HCM- RELATED PROGRESSION TO NYHA

VARIABLE CLASS III OR IV OR DEATH FROM HEART FAILURE OR STROKE

RELATIVE RISK p VALUE (95 % CI)

LV OUTLOW OBSTRUCTION ( > 30 mm Hg) 2.7 (2.0 - 3.5) < 0.001

NYHA CLASS II, III, OR IV AT ENTRY 3.4 (2.4 - 4.8) < 0.001

PAROXYSMAL OR CHRONIC ATRIAL AF 1.3 (1.1 - 1.6) 0.046

MAXIMAL LV THICKNESS > 30 mm - 0.09

FEMALE SEX 1.4 (1.1 - 1.8) 0.02

Maron et al NEJM 2003;348:295-303

Maron et al NEJM 2003;348:295-303

SUDDEN DEATH FROM HCM

VARIABLE RELATIVE RISK p VALUE

(95 % CI)

LV OUTLOW OBSTRUCTION ( > 30 mm Hg) 1.9 (1.1 - 3.5) 0.014

NYHA CLASS II, III, OR IV AT ENTRY - 0.12

PAROXYSMAL OR CHRONIC ATRIAL AF - 0.72

MAXIMAL LV THICKNESS > 30 mm - 0.82

FEMALE SEX - 0.75

Maron et al NEJM 2003;348:295-303

Maron et al NEJM 2003;348:295-303

CONSEQUENCES OF CHRONIC OUTFLOW GRADIENT

Increase in LV wall stress

Myocardial ischaemia

Cell death

Fibrosis

HAEMODYNAMIC SUBGROUPS IN HCM

Obstructive : gradient at rest > 30 - 50 mmHg

Provocable :mild gradient at restgradient > 30 - 50 mmHg with provocation

Latent :no gradient at restsignificant gradient with provocation

Nonobstructive :gradient < 30 mmHg under basal and provocable conditions

INTERVENTIONS TO INDUCE GRADIENTS

Amyl nitrite inhalation

Valsalva maneuver

Post-PVC response

Isoproterenol infusion

Dobutamine infusion

Standing posture

Physiologic exercise (during and after)

GRADIENT MAJORE APRES EXTRASYSTOLE

GRADIENT MAJORE PENDANT MANŒUVRE DE VALSALVA

DOBUTAMINE STRESS ECHO

DOBUTAMINE INFUSION

LV OBSTRUCTION DURING DOBUTAMINE STRESS ECHO

232 consecutive pts : normal DSE (no HCM)

31 pts (13%):LVOT vel. >3m/s (36 mmHg)

7 unable toexercise

24 underwentEx stress echo

Possible angina : 19

Dyspnea : 4

Syncope : 1

DSE vs Ex SE IN 24 PATIENTS

17 women , 7 men

Hypertension in 12 pts

LVOT diameter : 22 ± 2 mm (18-25 mm)

Basal septal diastolic thickness : 13 ± 2 mm (9-15 mm)

Peak velocity with Dobutamine : 4 ± 0.8 m/s (3-6.3)

Peak velocity with Exercise : range 0.9 to 2.2 m/s

No patient developed LV gradient

EXERCISE FOR DEFINING LATENT OBSTRUCTION

Immediately following treadmill or bicycle exercise

During and immediately after semi-supine exercise

No drug withdrawal

Exercise Echo in HCM

EXERCISE ECHO IN HCM

320 consecutive patients

119 pts (37%) : LV outflow tract gradient > 50 mmHg at rest

201 pts : exercise echo106 (52%) : dynamic obstruction > 30 mmHg 76 (38%) : substantial gradient > 50 mmHg 95 (47%) : nonobstructive form (< 30 mmHg)

Thus : 225/320 pts (70%) : outflow obstruction

Implications : more candidates for septal reduction therapy ??

Maron et al Circulation 2006;114:2232-9

Maron et al Circulation 2006;114:2232-9

Maron et al Circulation 2006;114:2232-9

Maron et al Circulation 2006;114:2232-9

CONCLUSIONS

Obstruction to LV outflow has prognostic importance

No role of stress testing when baseline gradient > 30-50 mmHg

Preferred provocative maneuver : exercise

Measurement of gradient mandatory during and after exercise

Dobutamine stress testing should not be used

The prognostic importance of provocable obstructionremains unknown

SYMPTOMS

DrugsBeta-blockerVerapamilDisopyramide

Drugrefractorysymptoms

Obstructive HCM(rest or provocation)

Alternativesto surgery

SurgerySeptal myectomy

DDDPacing

Alcoholseptal ablation

Non-ostructive HCM(rest and provocation

End-stage HF treatment ,heart transplant

TRAITEMENT DE L ’OBSTRUCTION SYMPTOMATIQUE

- Chirurgie : myotomie + myectomie septale haute

- Alcoolisation de la première septale :

. épaisseur à cause de l’infarctus induit

. élimination de l’obstacle à l’éjection

. hospitalisation courte

. mortalité 2% (taux similaire à celui de la chirurgie)

. bloc AV complet 25%,nécessitant stimulateur

. rarement infarctus massif

. courbe d’apprentissage

- Effets morphologiques différents

SURGICAL MYECTOMY vs ALCOHOL SEPTAL ABLATION

Cine and contrast-enhanced CMR before and afterseptal myectomy (n=24)septal ablation (n=24)

Myectomy:resected tissue always localized to anterior septum

Ablation: more variable effect transmural tissue necrosis,more inferiorly in basal septum extending into RV side of septum at mid-ventricular level 6 pts: sparing of the basal septum with residual gradient

LBBB in 46% after myectomyRBBB in 58% after ablation

8 of 47 pts(17%) :heart block requiring PMK (excluded)Valeti et al JACC 2007;49:350-7