Transcript CPC - NCCPeds

CPC
Hypertrophic Cardiomyopathy
FACTS of INTEREST
• Patient was relatively asymptomatic until
follow-up visit at WRAMC.
• Both his mother and older sibling had
hypertrophic cardiomyopathy but were
asymptomatic and without evidence of
obstruction. His father’s echo was
completely wnl
FACTS cont.
• His ECG showed voltage criteria for LVE
but there was no evidence of LV strain
pattern.
• His preop echo showed a midcavity
gradient of 100 mm HG.
• The diagnostic portion of his EP study
showed : LV 182/19,AAo 90/41,DAo 90/40
OPERATION: Morrow
Procedure
• Myotomy and myectomy of the
intraventricular septum.
• After an initial myectomy ,the gradient was
felt to be 35 but as the heart warmed up and
perfused better, the gradient was 50.
• Surgeons went back in, took out more tissue
and patient had gradient of 15.
POST OP
• Following the surgery, the patient was
found to have a residual gradient of about
30,depending on his level of agitation.
• He returned to being without symptoms. His
preop MR had been significantly reduced,
his subAS (HOCM) was significantly
reduced, and his AI was slightly worse.
• About 2.5 yrs later, his gradient was 30.
POST OP
• Following the surgery, the patient was
found to have a residual gradient of about
30,depending on his level of agitation.
• He returned to being without symptoms. His
preop MR had been significantly reduced,
his subAS (HOCM) was significantly
reduced, and his AI was slightly worse.
• About 2.5 yrs later, his gradient was 30.
POSTOP
• Patient has LBBB on ECG
• Holter 2 yrs post op shows no significant
rhythm disturbances. When
running,however, he looks a lot like V.Tach
• Patient remains on verapamil
DISCUSSION
• General: about .1-.2% of general population
• At least 50-70 different names
• Things it ain’t: secondary
hypertrophy,IDM,glycogen storage
diseases,acromegaly, myocardial Fe
deposition,athletic heart syndrome
GENETICS
• Probably autosomal dominant with variable
penetrance
• Familial in at least 50% of patients
• Seems to usually involve missense genes on
the B myosin heavy chain.
• There are about 1k genes response for
myocardial growth which may be why
there’s so much variation in families.
PATHOPHYSIOLOGY
• Although the massive hypertrophy would
seem to mainly affect systolic function, the
pathonomonic aberration is in diastolic
relaxation.
• The ventrical is noncompliant because of
increased muscle mass and fibrosis. Also
the coronaries are not well perfused during
diastole
PATHOPHYSIOLOGY cont.
• A large part of the LVOT obstruction is
because the anterior leaflet of the MV gets
in the way during systole(SAM). People
who are obstructed seem to have a more
anterior placement of their MV.
• People who are obstructed also seem to
have a more narrow LVOT in and of itself.
NATIONAL HX
• Mortality is twice as high in children.
• 50% who present in infancy die by 1 yr.
25% will eventually die.
• If you present after 1 yr the risk of failure is
lessened but the risk of sudden death is
higher.
• Hard to predict based on degree of
hypertrophy but the degree of obstruction is
• a factor.
NATIONAL HX cont.
• There seem to be groups with no
obstruction and only minimal gradient.
• HOCM is the most common cause of death
during exercise in children and
adolescents.May be as high as 5-7%/yr.
• Most common age is 10-35 yrs.
• Only selectors seem to be family hx and
recurrent syncope.
CLINICAL
• Murmur, chest pain,fatigue,syncope,
palpitations and dizziness.
• Murmur is harsh and peaks in midsystole.
Usually louder the more obstruction. There
is a blowing holosystolic murmur at the
apex which is the MR. This murmur is
increased by standing(decreased
preload,Valsalva(decreased pre and
afterload.
CLINICAL
• The MR murmur is decreased by lying
down(increased preload),
squatting(increased afterload) or verapamil.
• The ECG is abnormal in most cases with
95% of obstructive cases being abnormal.
25% of patients without obstruction may be
normal.
• Infants may have cardiomegaly on CXR
CLINICAL cont.
• Echo is the mainstay of diagnosis and
follow-up. Asymmetrical septal hypertrophy
and SAM are felt to be 95% specific for
HCM.
• ECHO can be used to separate from athletic
heart syndrome. In the latter,the LV free
wall seldom >15mm and thickness
decreases with cessation of training.
CLINICAL cont
• Invasive: ECHO probably better for fu but
cath good for assessing degree of LV
diastolic dysfunction. Also good for
showing degree of midcavity obstruction.
TREATMENT
• Beta blockers for tx of symptoms. They
appear to have no effect on the degree of
LVOT obstruction or frequency of sudden
death.
• Works by prolonging diastole and
decreasing heart rate. Also decrease
contractility.
TREATMENT cont.
• Calcium channel blockers: decrease
contractility and increase diastolic function.
• Verapamil : may be best but has been
associated with death in infants.Use
carefully if evidence of conduction
disturbances.
• Nifedipine:big vasodilator. May be bad in
obstructed infants.
TREATMENT cont.
• Avoid digitalis and other inotropes as they
may make obstruction worse. Remember
patients do better with a good preload so
diuretics may make them worse.
• Surgery: most effective. Complications
include complete heart block,septal
perforation, and inadequate. A point of
debate is whether to pull the MV as it
relieves obs.
TREATMENT cont.
• DDD pacing in the ventricular apex may
relieve symptoms but the method is
uncertain. This was the tx EP approach used
in our patient without success.
• Other option is to use amiodirone to tx
v.tach but not clearly related to decreased
death. Also helps with a.fib.
TREATMENT final
• Ami, myectomy and implantable
pacemakers may be the approach for
patients with inducible v. tach.