Updated: 7/7/2018

Cardiomyopathies

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Snapshot
  • A 16-year-old boy presents to his pediatrician for syncope. In the past few months, he had syncopal episodes when he played football, soccer, and sprinting. His family history includes sudden cardiac death in several relatives. An echocardiogram shows marked hypertrophy and abnormal systolic anterior leaflet motion of the mitral valve. (Hypertrophic cardiomyopathy)
Introduction
  • Clinical definition
    • cardiomyopathies intrinsically affect the myocardium, leading to systolic or diastolic dysfunction
      • these do not include changes in the myocardium secondary to hypertension, coronary artery disease, or valvular disorders
    • types of cardiomyopathies
      • dilated cardiomyopathy (most common)
      • restrictive/infiltrative cardiomyopathy
      • hypertrophic cardiomyopathy (obstructive vs non-obstructive)
      • dilated cardiomyopathy is most common
 
Cardiomyopathies

Dilated
Restrictive/Infiltrative
Hypertrophic 
Etiology
  • ABCD
    • Alcohol abuse
    • Beriberi (wet)
    • Coxsackie B viral myocarditis
    • Chronic Cocaine use
    • Chagas disease
    • Doxorubicin toxicity
  • Hemochromatosis
  • Sarcoidosis
  • Peripartum cardiomyopathy
  • Radiation therapy
  • Loffler endocarditis (with endomyocardial fibrosis and eosinophilic infiltrate)
  • Endocardial fibroelastosis (in children)
  • Amyloidosis
  • Sarcoidosis
  • Scleroderma
  • Hemochromatosis
  • Familial (most common)
    • autosomal dominant
    • mutations in sarcomere proteins (β-myosin heavy chain = myosin binding protein C > tropomyosin = troponin I/C - in order of frequency of mutations)
  • Idiopathic
Pathology
  • Systolic dysfunction from ↓ contractility and ↓ ejection fraction
  • Eccentric hypertrophy (sarcomeres added in series)
  • Stiff myocardium causes diastolic dysfunction
  • Preserved left ventricular systolic function
  • Diastolic dysfunction from compliance of left ventricle
  • Septal hypertrophy
  • Majority of cases are obstructive (hypertrophic obstructive cardiomyopathy)
  • Concentric hypertrophy (sarcomeres added in parallel)
Clinical presentation
  • Congestive heart failure
  • S3 sound
  • Systolic murmur
  • Progressive heart failure
  • Sudden cardiac death
  • S3 sound
  • + Kussmaul sign
  • Syncope with activity
  • Sudden cardiac death (especially in young athletes)
  • S4 sound
  • Systolic murmur without radiation
    • ↑ with Valsalva and standing up
    • ↓ with hand grip and squatting
Diagnostic studies
  • Chest radiography
    • ballooning of heart
  • Echocardiogram
    • dilated ventricles and ↓ ejection fraction
  • Electrocardiogram
    • bundle branch block
  • Chest radiography
    • cardiomegaly and pulmonary congestion
  • Echocardiogram
    • thickening of all structures
    • diastolic dysfunction
  • Endomyocardial biopsy
    • the most accurate test for etiology
  • Electrocardiogram
    • may have low voltages
  • Echocardiography
    • normal ejection fraction
    • hypertrophy
    • mitral regurgitation
  • Electrocardiogram
    • left ventricular hypertrophy
  • Histology
    • tangled and disoriented myofibrils
Treatment
  • Angiotensin-converting enzyme inhibitors
  • β-blockers
  • Spironolactone
  • Automatic implantable cardioverter/defibrillator
  • Biventricular pacemaker
  • Treat underlying condition
  • Diuretics
  • Heart transplant
  • Avoid athletic activities
  • β-blockers
  • Non-dihydropyridine calcium channel blockers
  • Implantable cardioverter/defibrillator
 

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Questions (7)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M1.CV.12) A 12-year-old girl with an autosomal dominant mutation in myosin-binding protein C is being evaluated by a pediatric cardiologist. The family history reveals that the patient's father died suddenly at age 33 while running a half-marathon. What was the likely finding on histological evaluation of her father's heart at autopsy? Review Topic

QID: 100528
1

Myocyte disarray

70%

(7/10)

2

Amyloid deposits

20%

(2/10)

3

Eosinophilic infiltration

0%

(0/10)

4

Wavy myocytes

10%

(1/10)

5

Viral particles

0%

(0/10)

M1

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PREFERRED RESPONSE 1

(M1.CV.219) A 19-year-old Caucasian male collapsed from sudden cardiac arrest while playing in a college basketball game. Attempts at resuscitation were unsuccessful. Post-mortem pathologic and histologic examination found asymmetric left ventricular hypertrophy and myocardial disarray. Assuming this was an inherited condition, the relevant gene most likely affects which of the following structures? Review Topic

QID: 100735
1

Cardiac cell sarcomere proteins

89%

(8/9)

2

Membrane potassium channel proteins

0%

(0/9)

3

Ryanodine receptors

0%

(0/9)

4

Autoimmune beta-cell antibodies

0%

(0/9)

5

Membrane sodium channels

11%

(1/9)

M1

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PREFERRED RESPONSE 1

(M1.CV.103) An 18-year-old African-American male presents to his family physician for a routine sports physical. He has a family history of sudden death at a young age. Upon physical examination the physician appreciates a systolic murmur. The intensity of the murmur increases when performing a valsalva maneuver. The physician refers the patient for an EKG, which is attached. What is the most likely cause of this murmur? Review Topic

QID: 100619
FIGURES:
1

Aortic valve stenosis

0%

(0/6)

2

Mitral stenosis

0%

(0/6)

3

Tricuspid stenosis

17%

(1/6)

4

Hypertrophic cardiomyopathy

83%

(5/6)

5

Benign systolic flow murmur

0%

(0/6)

M1

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PREFERRED RESPONSE 4

(M1.CV.140) A 66-year-old female with a past medical history significant for hypertension and breast cancer that is in remission after chemotherapy, presents to her primary care physician complaining of progressive dyspnea, decreased exercise tolerance, and paroxysmal nocturnal dyspnea. On chest auscultation you note an S3. A chest radiograph and echocardiogram are shown in Figure A. Which of the following medications is likely responsible for the patient's current presentation? Review Topic

QID: 100656
FIGURES:
1

Lisinopril

0%

(0/6)

2

Digoxin

0%

(0/6)

3

Cytarabine

0%

(0/6)

4

Hydrochlorothiazide

0%

(0/6)

5

Doxorubicin

100%

(6/6)

M1

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PREFERRED RESPONSE 5

(M1.CV.20) A 49-year-old man presents to his physician complaining of weakness and fatigue. On exam, you note significant peripheral edema. Transthoracic echocardiogram is performed and reveals a preserved ejection fraction with impaired diastolic relaxation. A representative still image is shown in Image A. Which of the following is likely the cause of this patient's symptoms? Review Topic

QID: 100536
FIGURES:
1

Previous treatment with doxorubicin

0%

(0/4)

2

Hemochromatosis

50%

(2/4)

3

Heavy, long-term alcohol consumption

25%

(1/4)

4

History of myocardial infarction

25%

(1/4)

5

History of a recent viral infection

0%

(0/4)

M1

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PREFERRED RESPONSE 2

(M1.CV.1) A 19-year-old basketball player unexpectedly collapses on the court. Several minutes later he returns to consciousness and is able to continue playing. This has happened several times before with similar outcomes. He had no significant past medical history. Which of the following is most likely to be found in this patient? Review Topic

QID: 100517
1

Atheromatous plaque rupture

0%

(0/16)

2

Coagulation necrosis with loss of nuclei and striations

0%

(0/16)

3

Septal hypertrophy

75%

(12/16)

4

Postductal coarctation of the aorta

0%

(0/16)

5

Cardiac myxoma

19%

(3/16)

M1

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PREFERRED RESPONSE 3
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