Cardiomyopathies

Question 1

What is dilated hypertrophy?

Answer 1

Eccentric hypertrophy, dilation (usually of all 4 chambers), results in ventricular dysfunction

Question 2

What is hypertrophic cardiomyopathy?

Answer 2

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

Question 3

What is restrictive cardiomyopathy?

Answer 3

Stiffened myocardium, impaired diastolic relaxation

Question 4

What are possible causes of dilated hypertrophy?

Answer 4

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

Question 5

What is the cause of HCM?

Answer 5

Familial/genetic disorder, 1/500 have it

Question 6

What are the causes of restrictive cardiomyopathy?

Answer 6

Idiopathic, amyloidosis, endomyocardial fibrosis

Question 7

What are the stages of dilated cardiomyopathy?

Answer 7

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

Question 8

How do you treat Stage A dilated cardiomyopathy?

Answer 8

Address underlying etiology (htn, stop smoking, lose weight, etc.)

ACE inhibitors if pt has vascular disease/ diabetes

Question 9

How do you treat Stage B dilated cardiomyopathy?

Answer 9

Underlying etiology

ACEI + beta blockers

Question 10

How do you treat Stage C dilated cardiomyopathy?

Answer 10

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

Question 11

How do you treat Stage D dilated cardiomyopathy?

Answer 11

Same as previous

Compassionate, end of life care

Heart transplant, chronic inotropes, permanent mechanical support, experimental surgery/drugs

Question 12

What is myocarditis?

Answer 12

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

Question 13

What is Chagas disease?

Answer 13

Leads to dilated cardiomyopathy– you can see the amastigotes in biopsy

Heart rhythm abnormalties & potentially sudden death

Also chronic stage causes GI dilation

Question 14

Which parts of the heart does rheumatic fever affect?

Answer 14

Pancarditis: pericardium, epicardium, endocardium (valves), myocardium

You can see Aschoff bodies in biopsy = a cardiac granuloma

Question 15

What infiltrative disorders can cause dilated cardiomyopathy?

Answer 15

Amyloid: extracellular accumulation of abnormal proteins

Sarcoid: granulomatous disease, biopsy only 50% sensitive

Hemochromatosis: accumulation of Fe both extra/ intracellularly

Hypereosinophilic Syndrome

Tumors

Question 16

What toxins can cause dilated cardiomyopathy?

Answer 16

Anthracyclines i.e. doxorubicin

Radiation injury

Alcohol

Question 17

What are the stages/ pathogenesis of anthracycline cardiotoxicity?

Answer 17

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

Question 18

What type of cardiomyopathy is associated with glycogen storage disease type IV (Andersen disease)?

Answer 18

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!

Question 19

What is characteristic of amyloid stains?

Answer 19

Amylodi deposits are extracellular

In H&E it’s light pink compared to myocytes

With Congo red stain, they are bright yellow/birefringent

Question 20

What is the pathophysiology of HCM?

Answer 20

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)

Question 21

What’s the presentation of HCM?

Answer 21

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

Question 22

What’s the highest predictor of sudden death in HCM?

Answer 22

Recent, unexplained syncope

Also: family history of sudden death

Less predictive is massive LVH

Least predictive: nonstained VT, drop in bp during exercise

Question 23

What are the physical exam findings in HCM?

Answer 23

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

Question 24

How do you manage HCM?

Answer 24

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