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
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
- Mayo approach
- Echo on every one in Mayo.
- Exercise stress test. Normal blood pressure resp is to increas 25 m hg. Filure to rise or a drop is associated with SCD. Seocnd tier risk fx. Not a primary dirver to determine need for and AICD.
- Holter
- FH
- Gadolinium: If hyperenchecment then AICD, if neg then no AICD. a tie breaker
Treax
- Avoid heavy weight lifting, comp sports,
- 40% of young athlete deaths are due to HCM
- Avoid dehdration
- Avoid caffiene
- Avoid diuretics
- Avoid inotropes
- Encourage hydration
- take meds away like vasodilators like amlodipine
Myectomy
- Debate over myomectomy and septal ablation, unlikely to be asked about this
- Indications for myecotmy
- LVOT > 40,
- Symptoms refractory to drugs
- Operative mortality only 0.5%
- Gradient goes from 67 to 3 mm Hg
95% become class 1 or 2. Survivla = age matched cohort after myectom Less need for AICD, myectomy patients have less discharge of their AICD Dont tell patients it may save lives, but it might. Drugs before mechanical therapy, mechanical therapy only if drugs fail Used to add CCB after beta blocker, but now could go to myectomy rather than add CCB as in the past. If you fail beta blocker, cna move on to myectomy Sever MR gets better with myectomy, dont need repair (maybe 1% of patients)
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