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
QUESTIONS 1 of 7 1 2 3 4 5 6 7 Previous Next Lab Values Blood Hematologic Cerebrospinal Sweat, Urine, and BMI 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/LFemale: 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/mLFemale: 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/dL2-h postprandial:<120 mg/dL Growth hormone - arginine stimulation Fasting: <5 ng/mLProvocative 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/mm3Female: 3.5-5.5 million mm3 Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/hFemale: 0-20 mm/h Hematocrit Male: 41%-53%Female: 36%-46% Hemoglobin A1c ≤ 6 % Hemoglobin, blood Male: 13.5-17.5 g/dLFemale: 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/kgFemale: 28-45 mL/kg Red cell Male: 20-36 mL/kgFemale: 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/minFemale: 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 hFemale: 2.0-8.0 mg/24 h 17-Ketosteroids, total Male: 8-20 mg/24 hFemale: 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 Calculator ( ) xy AC 7 8 9 ÷ 4 5 6 × 1 2 3 - 0 . = + (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: A 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 Select Answer to see Preferred Response PREFERRED RESPONSE 2 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (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 Select Answer to see Preferred Response 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 Select Answer to see Preferred Response 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: A 1 Aortic valve stenosis 0% (0/7) 2 Mitral stenosis 0% (0/7) 3 Tricuspid stenosis 14% (1/7) 4 Hypertrophic cardiomyopathy 86% (6/7) 5 Benign systolic flow murmur 0% (0/7) M1 Select Answer to see Preferred Response 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: A 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 Select Answer to see Preferred Response PREFERRED RESPONSE 5 (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 Select Answer to see Preferred Response PREFERRED RESPONSE 3