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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.
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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.
