Cardiology Board Review in cardiomyopathy
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Classification
CMPs can be divided into genetic, mixed and acquired ones.
Dilated CMP
- Look for reversible causes alcohol, hemochromatosis, and soa
Restrictive Cardiomyopathy
- 5 yr survival only 64%, CCB, diuresis are mainstays. SOmewhat preload dependent. Slow heart rate and may drop CO., transplant may be best option.
- Atrial bigger than ventricles, hige atria to fill ventricles
- Little atrial contribution to filling since pressure so high
- Non-hypertrophied ventricles
- Restrictive physiology not the same as restr cmp
- Classic square root sign
Muscle or Myocardial
===Endomay
Hypereosinophilia
- Bright endomyocardium on echocardiogram
- May affect valve function with progressive scarring
- Mobile scars may require chemotherapy
Amyloid Cardiomyopathy
- Small volts on EKG
- Shimmering on Echo
- Very thick myocardium
- Often a small pericardial effusion
Arrhythmogenic Right Ventricular Dysplasia
- Fibrofatty replacement of RV free wall, almost no muscle left
- Repol abn on EKG
- 30% have + FH
- AICD and avoid athletics
Non-Compaction Cardiomyopathy
- More commonly diagnoses now
- Heart muscle does not compact down in utero
- Beta myosin heavy chain most common
- See crypts and ressesin wall
- MRI a good imaging modality
- Dyspnea is the most common symptom, may not have may sx
- Increased risk of SCD
- If systolic function normal: Risk strat for SCD using HCM criteria, treat with stage B CHF
- Low EF: treat like HCM
Class 2B recommendation fo AICD If +FH, SVT put in AICD
HOCM
- Thick walls
- Myocardial disarray
- Prevalence is 1:500
- Average age of death not that different than gen pop
- 1% / ye ris of SCD
- Autosomal dom inheritacne
- Contrainidcations to competitive athletics, but can hav e ehalthy lifestyle
- Meds only to reat symptoms
- Pt with +FH, 2/6 murmur, brisk carotid upstroke in HCM, apical impulse bifid or trifid, bearin down increases murmur, loud whenyou stand up after qauting, most dynamic of the murmurs, EKG narrow symmetric inverted t waves. 5% have normal ECG.
- thick walss on echo Ithink amyloid, renal failure, glycogen storage dz, anderson Fabrys, or Fredierichs
- Athletes heart: does not exist in as many people as you think. 1% have increased will thickness. 18-22 mm is too big. Not common in weekend warriors.
Distinguish HCM vs athletic ehart. More wall than cavity then HOCM,
- Spetum, base can be involved. THere is an apical variant
- Apical treated no differently, not benign
- Genetics:
- abnromal sarcomere genetics, 14 mutations, dont know final common pathway. 50% of HOCM have a genetic abn. Limits role of testing
genotype doesnt teel you if patient will respon to a therpay Only identifies family memebrs
- Family screening: screening start at puberty or onset of adolescence if child of an HCM patient, then every yeart ill no longer a athlelet. One time echo not good enough stop in adults at age 60 q 5 years as an adilt. iF a mutation is present in a pt, then screen first degree family memb. If no mutation in a ptiatient, screen family with imaging
Tx
- Avoid heavy weight lifting, comp sports,
- 40% of young athlete deaths are due to HCM
- Avoid dehdration
- Avoid caffiene
- no diuretics
- no inotropes
- hydrate
- take meds away
- Debate over myectom and ablation.
- Indications for myecotmy
LVOT > 40, sx refractory drugs are indications for ablation or myectomr Opmort 0.5% gradient 67 to 3 95% become class 1 or 2. Survivla = age matched chohort Less need for AICD, myectomy patients have less discharge of their AICD Dont tell patients it may save lives, but it might.
Ablation
- If it works it works as well as myectomy
20-30% dont respond complicaitons like chb in 20% mortalityr ate is 1.9%, not going down, similar to infarcts of same size since we are creating an infarct. if pre-existing LBBB, the ablation wacks out RBB a dn they will need PPM. Younger pts due better with myectomy
Guidelines
- Indicated if drug refractory symptoms
if surg candidate then myecoty 2a, ablation 2b not surg candate then ablation a 2a indication
Prognosis
- 1% per year risk of SCD
- IndependentRisk factors:
- LVOT obstrution, syncope, worse with exercise
- serverity of LVH
- Fibrosis on MRI
- Fh
Who needs a defib
- Class 1: Prior CPR
- Class 2a:
FH SCD, wall > 30 mm, unexplained syncope Non sustained VT and abnormal exercise response and + hyperencehament 2b
Bottom Line
No risk factors: Reassure Prior SCD: AICD Sustained VT: AICD
Pathophysiology
- Diastolic dysfun in 100%
- 70% have dynamic obstruction
- Suendo ischemia
- MR proportion to gradient
- Gradient reduces forward CO
- Sx vary from day to day due to graient, Na intake, temperature. AS sx are constant with constant graient
- Mitarl vale like your hand hanging out a car and gets pulled back
- MR anteriorly directed means there may be a primary problemw ith the mitral voalve
- Sx with reduced pre load and increased contractily