Cardiomyopathies Flashcards
What is dilated hypertrophy?
Eccentric hypertrophy, dilation (usually of all 4 chambers), results in ventricular dysfunction
What is hypertrophic cardiomyopathy?
Concentric hypertrophy, abnormally thickened ventricular wall– usually asymmetric hypertrophy of ventricular septum, abnormal diastolic relaxation
Swirly myocyte (concentric hypertrophy) pattern in biopsy
Genetic: 1/500 have it! Most unaware
What is restrictive cardiomyopathy?
Stiffened myocardium, impaired diastolic relaxation
What are possible causes of dilated hypertrophy?
Idiopathic
Familial/genetic
Inflammatory: infectious (secondary to viral infection), noninfectious= conn tiss diseases, peripartum cardiomyopathy, sarcoidosis
Toxic: chronic alcohol ingestion, chemotherapeutic agents (doxorubicin)
Metabolic: hypothyroidism, chronic hypocalcemia/ hypophosphatemia
Neuromuscular: muscular or myotonic dystrophy
Ischemic injury, uncorrected valve problems
What is the cause of HCM?
Familial/genetic disorder, 1/500 have it
What are the causes of restrictive cardiomyopathy?
Idiopathic, amyloidosis, endomyocardial fibrosis
What are the stages of dilated cardiomyopathy?
Stage A: high risk but no structural heart disease or HF
Stage B: structural heart disease but no signs/ symptoms of HF
Stage C: Structural heart disease with prior or current symptoms of HF
Stage D: Refactory HF
How do you treat Stage A dilated cardiomyopathy?
Address underlying etiology (htn, stop smoking, lose weight, etc.)
ACE inhibitors if pt has vascular disease/ diabetes
How do you treat Stage B dilated cardiomyopathy?
Underlying etiology
ACEI + beta blockers
How do you treat Stage C dilated cardiomyopathy?
Underlying etiology + reduce dietary salt restriction
Diuretics, ACEI, beta blockers
Some patients can get aldosterone antagonist, ARBs, digitalis, hydralazine/nitrates
Devices: Ventricular pacing/ implantable defibrilators also an option
How do you treat Stage D dilated cardiomyopathy?
Same as previous
Compassionate, end of life care
Heart transplant, chronic inotropes, permanent mechanical support, experimental surgery/drugs
What is myocarditis?
Inflammation of heart muscle (usually autoimmune, secondary to viral infection)
Leads to dilated cardiomyopathy
Can be distinguished from ischemic type infiltration of WBCs bc myocytes retain nuclei and sometimes you see the fungus/bacteria
What is Chagas disease?
Leads to dilated cardiomyopathy– you can see the amastigotes in biopsy
Heart rhythm abnormalties & potentially sudden death
Also chronic stage causes GI dilation
Which parts of the heart does rheumatic fever affect?
Pancarditis: pericardium, epicardium, endocardium (valves), myocardium
You can see Aschoff bodies in biopsy = a cardiac granuloma
What infiltrative disorders can cause dilated cardiomyopathy?
Amyloid: extracellular accumulation of abnormal proteins
Sarcoid: granulomatous disease, biopsy only 50% sensitive
Hemochromatosis: accumulation of Fe both extra/ intracellularly
Hypereosinophilic Syndrome
Tumors
What toxins can cause dilated cardiomyopathy?
Anthracyclines i.e. doxorubicin
Radiation injury
Alcohol
What are the stages/ pathogenesis of anthracycline cardiotoxicity?
Acute: EKG changes, LV dysfunction transient/ reversible
Late-onset: ventricular dysfunction and arrhythmias
Dilated cardiomyopathy: cumulative, dose dependent, irreversible, progressive
CHF in 2-3%
Pathology: cytoplasmic vacuoles= dilated SR, loss of myofibrils, little/no inflammation, end-stage myocyte hypertrophy & interstitial fibrosis
What type of cardiomyopathy is associated with glycogen storage disease type IV (Andersen disease)?
Restrictive cardiomyopathy: thick walls of ventricles on ECHO but low voltage would be seen on EKG. Also you’d see high/equal diastolic pressures in the heart
You can see stored glucose within cells upon biopsy
Same principles hold for other infiltrative diseases!
What is characteristic of amyloid stains?
Amylodi deposits are extracellular
In H&E it’s light pink compared to myocytes
With Congo red stain, they are bright yellow/birefringent
What is the pathophysiology of HCM?
Impaired diastolic filling –> increased filling pressure
Myocardial ischemia
Mitral regurgitation
Arrhythmias: atrial or spontanous ventricular (which are the dangerous ones & common cause of sudden death)
What’s the presentation of HCM?
Most asymptomatic (70-50%)
Angina: exertional (75%)
Syncope: exertional or during dehydration (too much preload reduction i.e. cold flu)
Dyspnea: secondary to mitral regurgitation (90% who have symptoms)
Sudden death
What’s the highest predictor of sudden death in HCM?
Recent, unexplained syncope
Also: family history of sudden death
Less predictive is massive LVH
Least predictive: nonstained VT, drop in bp during exercise
What are the physical exam findings in HCM?
Palpable S4 – “triple ripple”
Prominent “a” wave– secondary to S4 (when LA or RA contract into stiff, noncompliant ventricle)
Rapid upstroke carotid pulse
Harsh systolic ejection murmur across entire chest
Mitral regurgitation: separate murmur
Valsalva maneuvers increase intensity of these findings
How do you manage HCM?
If neg phenotype but positive genotype: follow
Mild/no symptoms: follow/ possible drug therapy
If progressive heart failure symptoms: drug therapy
AFib: drugs, cardioversion, anticoag
High risk of sudden death: implant cardioverter-defib
If non-obstructive HCM (of outlfow from LV): heart transplant
If obstructive: ventricular-septal myotomy/myectomy OR alcohol septal ablation/chronic pacing
