cardiomyopathy Flashcards
cardiomyopathy
a heterogeneous group of diseases of the myocardium associated with mechanical &/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilatation and are due to a variety of causes that frequently are genetic
Cardiomyopathies either are confined to the heart or are a part of ??
generalized systemic disorders, often leading to cardiovascular death or progressive heart failure-related disability
Cardiomyopathy: 3 Categories + 2
DILATED
HYPERTROPHIC
RESTRICTIVE
ARRHYTHMOGENIC RV (don’t know as much)
ISCHEMIC – not focused upon in this lecture (most common in developed world, CAD)
Dilated cardiomyopathy
Congestive, DCM, IDC
most common cause of cardiomyopathy in the world
Dilatation and impaired contraction of the left or both ventricles.
hypokinetic left ventricle, and systolic dysfunction
Hypertrophic cardiomyopathy (IHSS, HCM, HOCM, ASH)
Left and/or right ventricular hypertrophy, often asymmetrical, which usually involves the inter ventricular septum
with or without left ventricular obstruction
Restrictive (Infiltrative)
cardiomyopathy
Restricted filling and reduced diastolic size of either or both ventricles with normal or near-normal systolic function.
Arrhythmogenic right ventricular cardiomyopathy (ARVD)
Progressive fibro-fatty replacement of the right ventricle
Dilated Cardiomyopathy: Background
CONGESTIVE presentations
Can be *inherited*
True cause: *unknown*
CHAMBER ENLARGEMENT
IMPAIRED SYSTOLIC FUNCTION:
right, left, or biventricular
Myocyte injury and fibrosisWide spectrum of causes of Dilated Cardiomyopathy (DCM)
Idiopathic (typically viral) Genetic ( 20-30%) Inflammatory (infectious and noninfectious) Toxic (etOH most common, chemo agents) Metabolic Neuromuscular Major ischemic episode
DCM Incidence / Prognosis
Prevalence is 36/100,000 population
3rd most common cause of heart failure
Middle age, men > women
Annual mortality: 12% !
Most frequent cause of heart transplantation
DCM accounts for approximately 10,000 deaths and 46,000 hospitalizations per year in the US
Complete recovery is rare
DCM primary vs secondary
Primary (idiopathic) is a disease of unknown etiology that principally affects the myocardium leading to LV dilation and systolic dysfunction
Secondary causes include ischemia, alcoholic, peripartum, post-infectious, viral
DCM causes2
Toxin induced:
alcohol
anthracycline
cobalt
catecholamine
Radiation
Infectious:
viral / HIV
parasitic
Metabolic:
starvation
thiamine deficiency
(beriberi)
thyrotoxicosis
Sarcoidosis
Hemochromatosis
Peripartum/postpartum
cardiomyopathy
Genetic
heart failure dx
done clinically, no definitive lab tests
DCM: Symptoms/Signs of heart failure
Pulmonary congestion (left heart failure) dyspnea (rest, excertional, nocturnal), orthopnea
Systemic congestion (right heart failure) edema, nausea, abdominal pain, nocturne
Cardiac exam reveals -> S3, S4 and murmur of TR and/or MR
Low CO
Hypotension, tachycardia, tachypnea
Fatigue and weakness
DCM: arrhythmia
Atrial fibrillation, conduction delays, complex PVC’s, sudden death
DCM dx
CXR (enlarged heart, CHF)
EKG (tachycardia, A-V block, LBBB, NSSTT changes, PVC’s)
Echo (left ventricular dilation, global hypo kinesis, low EF)
Myocardial biopsy, rare
Cardiac catheterization (R/O CAD): -if age >40, ischemic history, high risk profile, abnormal ECG
DCM tx
(*lifestyle*) Limit activity based on functional status Salt restriction Fluid restriction Initiate medical therapy
DCM med therapy
Diuretics (don’t increase longevity, improve symptoms, except loop-spironolactone)
the following improve mortality:
Beta Blockers, ACE/ARB
Hydralazine/nitrate combination if cannot tolerate ACE/ARB
Spironolactone if EF less than 35% with Class III/VI HF
Anticoagulation prn (EF less than 30%, history of LV thrombus or embolic events)
Implantable defibrillators if EF less than 35% on optimal medical therapy
DCM more invasive tx
Cardiac transplantation: -DCM is most common indication for cardiac transplantation Survival after transplant is 80% one year 70% 5 years
Left Ventricular Reduction Procedures
LV-reshaping
Hypertrophic Cardiomyopathy (HCM): Background
Genetic disease characterized by hypertrophy of the left ventricle with marked variable clinical manifestations morphologic and hemodynamic abnormalities
Prevalence 2:1000 (more than DCM?), younger pts
concentric or localized
the heart on HCM
Small LV cavity, septal hypertrophy which can be asymmetric (ASH), systolic anterior motion of the mitral valve leaflet (SAM), +/- obstruction of left ventricular outflow with low stroke volume, but elevated EF
HCM manifestations
Hyperdynamic systolic function
LVH and LV outflow obstruction
Diastolic dysfunction
Leads to pulmonary congestion
HCM Dynamic LV outflow tract obstruction
Outflow tract gradient (>30 mm Hg), considered severe if >50 mm Hg (occurs in 25-30% of cases leading to name hypertrophic obstructive cardiomyopathy)
the original “classic” feature
we now know that it is absent in about half of the patients, and the severity of the obstruction varies greatly in those who do have it
HCM complications
Dynamic LV outflow tract obstruction Diastolic dysfunction Impaired diastolic filling, filling pressure Myocardial ischemia Mitral regurgitation Arrhythmias
HCM The causes of obstruction:
- narrowed left ventricular outflow tract due to hypertrophied interventricular septum
- anterior displacement of the mitral valve leaflets during systole (SAM- systolic anterior motion of the mitral valve).
why heart hypertrophies
heart tries to squeeze harder against restriction of outflow tract
HCM: The severity of obstruction increases with:
- any maneuver that increases the force of contraction (exercise, positive inotropic agents)
- any maneuver that decreases filling of the ventricle (dehydration, squatting–>standing, tachycardia, valsava)
