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.