Card - Path (Part 4: Cardiomyopathies & CHF)

Question 1

What is the most common cardiomyopathy? For what percentage of cases does it account?

Answer 1

Dilated cardiomyopathy; Most common cardiomyopathy (90% of cases)

Question 2

What 2 general causes of dilated cardiomyopathy that often occur? What are 8 other, more specific etiologies?

Answer 2

Often idiopathic or congenital; Other etiologies include Alcohol abuse, wet Beriberi, Coxsackie B virus myocarditis, chronic Cocaine use, Chagas disease, Doxorubicin toxicity, hemochromatosis, and peripartum cardiomyopathy; Think: “ABCCCD”

Question 3

What are 4 clinical findings associated with dilated cardiomyopathy?

Answer 3

Findings: (1) heart failure (2) S3 (3) dilated heart on echocardiogram (4) balloon appearance of heart on CXR

Question 4

What are 7 treatments for dilated cardiomyopathy?

Answer 4

Treatment: (1) Na+ restriction, (2) ACE inhibitors, (3) Beta-blockers, (4) Diuretics, (5) Digoxin, (6) Implantable cardioverter defibrillator (ICD), (7) Heart transplant

Question 5

What kind of cardiac dysfunction results from dilated cardiomyopathy?

Answer 5

Systolic dysfunction ensues

Question 6

What kind of hypertrophy occurs with dilated cardiomyopathy, and why?

Answer 6

Eccentric hypertrophy (sarcomeres added in series)

Question 7

What percentage of hypertrophic cardiomyopathy cases are familial, autosomal dominant? What is commonly the mutation?

Answer 7

60-70% of cases are familial, autosomal dominant (commonly a Beta-myosin heavy-chain mutation).

Question 8

With what condition can hypertrophic cardiomyopathy rarely be associated?

Answer 8

Rarely can be associated with Friedreich ataxia

Question 9

With what patient population is hypertrophic cardiomyopathy associated, and in what context?

Answer 9

Cause of sudden death in young athletes, due to ventricular arrhythmia

Question 10

What are 2 clinical findings associated with Hypertrophic cardiomyopathy?

Answer 10

Findings: (1) S4 (2) Systolic murmur

Question 11

What is the treatment for hypertrophic cardiomyopathy? What is the treatment for particularly high risk patients?

Answer 11

Treatment: Cessation of high-intensity athletics, use of Beta-blocker or non-dihyropyridine calcium channel blocks (e.g., verapamil). ICD if patient is high risk.

Question 12

What kind of cardiac dysfunction occurs with hypertrophic cardiomyopathy?

Answer 12

Diastolic dysfunction ensues.

Question 13

What are the gross and histologic findings that characterize cardiac hypertrophy?

Answer 13

Marked (concentric) ventricular hypertrophy, often septal predominance. Myofibrillar disarray and fibrosis

Question 14

What pathophysiology and outcome(s) characterize the obstructive HCM subset?

Answer 14

Obstructive HCM (subset): Hypertrophied septum too close to anterior mitral leaflet => outflow obstruction => dyspnea, possible syncope

Question 15

What are 6 major causes of Restrictive/infiltrative cardiomyopathy?

Answer 15

Major causes include (1) sarcoidosis, (2) amyloidosis, (3) postradiation fibrosis, (4) endocardial fibroelastosis (thick fibroelastic tissue in endocardium of young children), (5) Loffler syndrome (endomyocardial fibrosis with a prominent eosinophilic infiltrate), and hemochromatosis (dilated cardiomyopathy can also occur)

Question 16

What characterizes endocardial fibroelastosis? With what kind of cardiomyopathy is it associated?

Answer 16

Endocardial fibroelastosis (thick fibroelastic tissue in endocardium of young children); Restrictive cardiomyopathy

Question 17

What characterizes Loffler syndrome? With what kind of cardiomyopathy is it associated?

Answer 17

Loffler syndrome (endomyocardial fibrosis with a prominent eosinophilic infiltrate); Restrictive cardiomyopathy

Question 18

With what cardiomyopathies is hemochromatosis associated?

Answer 18

Restrictive/infiltrative; Hemochromatosis (dilated cardiomyopathy can also occur)

Question 19

What kind of cardiac dysfunction occurs in restrictive/infiltrative cardiomyopathy?

Answer 19

Diastolic dysfunction ensues

Question 20

What ECG finding characterizes restrictive/infiltrative cardiomyopathy? For what cause of restrictive/infiltrative cardiomyopathy is this especially the case?

Answer 20

Can have low-voltage ECG despite thick myocardium (especially amyloid)

Question 21

What is CHF?

Answer 21

Clinical syndrome of cardiac pump dysfunction

Question 22

What are 3 symptoms and 3 signs that characterize CHF?

Answer 22

Symptoms include dyspnea, orthopnea, and fatigue; Signs include rales, JVD, and pitting edema

Question 23

What occurs as a result of systolic versus diastolic dysfunction in CHF?

Answer 23

Systolic dysfunction - low EF, poor contractility, often secondary to ischemic heart disease or DCM; Diastolic dysfunction - normal EF and contractility, impaired relaxation, decreased compliance

Question 24

To what is systolic dysfunction in CHF often secondary?

Answer 24

Often secondary to ischemic heart disease or DCM

Question 25

From what does right heart failure most often result? Other than this, what usually causes right heart failure, and in what context?

Answer 25

Right heart failure most often results from left heart failure. Isolated heart failure is usually due to cor pulmonale.

Question 26

What are 4 drugs that that decrease mortality in CHF? What 2 drugs are used in CHF mainly for symptomatic relief? What drug therapy improves both symptoms and mortality in select patients?

Answer 26

ACE inhibitors, Beta-blockers (except in acute decompensated HF), angiotensin II receptor blockers, and spironolactone decrease mortality. Thiazide or loop diuretics are used mainly for symptomatic relief. Hydralazine with nitrate therapy improves both symptoms and mortality in select patients.

Question 27

What are 2 general abnormalities of CHF (i.e., not directly related to left or right heart failure)? What causes each?

Answer 27

(1) Cardiac dilation - Greater ventricular end-diastolic volume (2) Dyspnea on exertion - Failure of CO to increase during exercise

Question 28

What are 3 abnormalities of CHF associated with left heart failure? What defines and/or causes each?

Answer 28

(1) Pulmonary edema - increased pulmonary venous pressure => pulmonary venous distention and transudation of fluid. Presence of hemosiderin-laiden macrophages (“heart failure” cells) in lungs. (2) Orthopnea - Shortness of breath when supine: Increased venous return from redistribution of blood (immediate gravity effect) exacerbates pulmonary vascular congestion. (3) Paroxysmal nocturnal dyspnea - breathless awakening from sleep: Increased venous return from redistribution of blood, reabsorption of edema, etc.

Question 29

What is a key histologic effect in the lungs during CHF, and what causes this?

Answer 29

Pulmonary edema - increased pulmonary venous pressure => pulmonary venous distention and transudation of fluid. Presence of hemosiderin-laiden macrophages (“heart failure” cells) in lungs.

Question 30

What are 3 abnormalities of CHF associated with right heart failure? What causes each?

Answer 30

(1) Hepatomegaly (nutmeg liver) - Increased central venous pressure => Increased resistance to portal flow. Rarely, leads to “cardiac cirrhosis”. (2) Peripheral edema - Increased venous pressure => Fluid transudation (3) Jugular venous distention - Increased venous pressure

Question 31

Draw a diagram relating the following aspects of CHF with physiological compensation and related pathology: (1) Decreased LV contractility (2) Pulmonary edema (3) Peripheral edema (4) Increased preload, Increased cardiac output (compensation).

Answer 31

See p. 291 in First Aid 2014 for visual near middle right of page