PANCE Blueprint Cardiology (13%)

Cardiomyopathy (PEARLS)

The NCCPA™ PANCE Cardiology System Content Blueprint includes 3 different types of cardiomyopathy

Cardiomyopathy translates to “heart muscle disease,” so cardiomyopathy is a broad term used to describe a variety of issues that result from disease of the myocardium, or heart muscle.
Types of cardiomyopathies

  • Dilated cardiomyopathy: ventricles enlarge and weaken - inherited in about one-third of cases,  may also result from alcohol, heavy metals, coronary artery disease, cocaine use, and viral infections.
  • Hypertrophic cardiomyopathy: the heart muscle enlarges and thickens - inherited autosomal dominant
    • Obstructive: The most common type, hypertrophic obstructive cardiomyopathy (HOCM) means the wall (septum) between the left ventricle and right ventricle thickens. This can block (obstruct) blood flow from the left ventricle to the aorta (the body's main artery).
    • Nonobstructive: In nonobstructive HCM, the heart muscle thickens but doesn't block blood flow.
  • Restrictive cardiomyopathy: ventricle stiffens - may be caused by amyloidosis, hemochromatosis, and some cancer treatments
  • Arrhythmogenic right ventricular dysplasia (ARVD): fatty replacement of myocardium - genetic defect
  • Takotsubo cardiomyopathy (broken heart syndrome): non-ischemic cardiomyopathy in which there is a sudden temporary weakening of the muscular portion of the heart -extreme emotional or physical stress

Major categories of cardiomyopathy

Impaired Systolic Function
Dilated Cardiomyopathy
Patient will present as → a 68-year-old patient who comes to the office because of increased shortness of breath for four months. His symptoms are particularly bad at night. Medical history includes long-standing hypertension and alcoholism. Examination shows a displaced apex beat and normal breath sounds. Cardiac auscultation shows an S3 gallop and a pan-systolic murmur radiating to the axilla. The chest X-ray shows an enlarged left ventricular shadow.

Dilated cardiomyopathy is the most common type (95%) of cardiomyopathy and is a condition in which an index event or process (such as an MI) damages the myocardium, weakening the heart muscle resulting in reduced strength of ventricular contraction, and dilation of the left ventricle

  • Reduced contraction strength, large heart
  • Causes include ischemia (CAD, MI, arrhythmia), genetics, excess alcohol, postpartum, chemotherapy, endocrine disorders, viral infections, cocaine use, heavy metals
    • Inherited in 1/3 of cases
  • Physical exam: Dyspnea, S3 gallop, rales, cardiomegaly (displaced apical impulse), edema, jugular venous distention - systolic heart failure
  • It can cause valve regurgitation and arrhythmias
"An S3 gallop signifies the end of rapid ventricular filling in the setting of fluid overload and is often associated with dilated cardiomyopathy."

DX: Echocardiography is the most definitive diagnosis - demonstrates left ventricular dilation and dysfunction and low cardiac output with poor EF (< 50%, but often less than 30%)

  • EKG will show nonspecific ST/T wave changes.
  • CXR often shows a balloon-like heart -  will show cardiomegaly and pulmonary congestion

TX: βblocker + ACE + Loop Diuretic

  • Use the mnemonic AABCD (anticoagulants, ACE-I, β-blockers, calcium channel blockers, and diuretics/ digoxin )
  • Increase cardiac contractility - digitalis
  • Treatment in extreme cases includes heart transplant or left ventricular assist device
  • Abstain from alcohol and drug use

Blausen 0165 Cardiomyopathy Dilated

Impaired Diastolic Function
Hypertrophic Obstructive Cardiomyopathy (HOCM)
Patient will present as → a 25-year-old man is brought to the ED because he collapsed while playing tennis 20 minutes ago. Medical history includes unexplained chest pain and shortness of breath while exercising for three years. Family history includes an uncle who died of an unknown cardiac pathology at the age of 23. Cardiac auscultation shows a 2/6 systolic murmur is heard at the left of the sternum between the first two ribs. The murmur becomes louder when the patient performs a Valsalva maneuver and decreases with squatting.

The hypertrophic portion of the septum - LV outflow tract is narrowed - during systole, and obstruction worsened with increased contractility

Blausen 0166 Cardiomyopathy Hypertrophic

Presentation: A young athlete with a positive family history has a sudden death or syncopal episode

  • Inherited autosomal dominant - screen family members
  • Presents in early adulthood
  • Not to be confused with hypertrophy of elite athlete

Physical Exam:

  • Sustained PMI, bifid pulse, S4 gallop
  • Murmur: High-pitched mid-systolic murmur at LLSB. Increased with Valsalva and standing (less blood in the chamber)
    • Decreased with squatting (more blood in the chamber)
"The murmur due to HCM will increase in intensity with any maneuver that decreases the volume of blood in the left ventricle (such as standing abruptly or the strain phase of a Valsalva maneuver ). "

DX: Diagnosis is by echocardiography or MRI

  • Echo is the key to diagnosis and will show left ventricular hypertrophy with a thickened septum, small left ventricle, and diastolic dysfunction
  • EKG will show nonspecific ST and T-wave changes and left ventricular hypertrophy

TX: β-blockers (metoprolol) and/or rate-limiting Ca channel blockers (usually verapamil) to decrease myocardial contractility and slow the heart rate and thus prolong diastolic filling and decrease outflow obstruction

  • Avoid nitrates and other drugs that decrease preload (eg, diuretics, ACE inhibitors, angiotensin II receptor blockers) because these decrease LV size and worsen LV function
  • Digoxin is contraindicated since it increases the force of contraction, which can increase the obstruction
  • Consider an implantable cardioverter-defibrillator for patients with syncope or sudden cardiac arrest
  • Cessation of high-intensity athletics
  • Surgical or alcohol ablation of the hypertrophied septum
Restrictive Cardiomyopathy
Patient will present as → a 58-year-old man complaining of several months of worsening shortness of breath and ankle swelling. He denies palpitations, lightheadedness, syncope, or chest pain. He has a past medical history significant for hereditary hemochromatosis.  On physical exam, his temperature is 37 C (98.6 F), pulse is 78, blood pressure is 130/72 mm Hg, and respiratory rate is 16. He has elevated jugular venous pressure, diminished breath sounds at the lung bases, tender hepatomegaly, and bilateral pitting ankle edema. There are no murmurs, rubs, or gallops. EKG shows low-voltage QRS complexes without any signs of ischemia. His chest x-ray shows a normal-sized heart and bilateral pleural effusions. Echocardiography shows symmetrical thickening of the left ventricle, normal left ventricular volume, and mildly reduced systolic function.

Right heart failure with a history of an infiltrative process

  • Etiology: Amyloidosis, sarcoidosis, hemochromatosis, scleroderma, fibrosis, and cancer (radiation and chemotherapy)
  • Physical Exam:
    • Pulmonary HTN present
    • Normal ejection fraction, normal heart size, large atria, normal left ventricular wall, early diastolic filling

DX: Echocardiography shows a normal left ventricular ejection fraction. Common findings include dilated atria and myocardial hypertrophy

  • The ECG is usually nonspecifically abnormal, showing ST-segment and T-wave abnormalities and sometimes low voltage
  • If the diagnosis is still in doubt, MRI can show abnormal myocardial texture in disorders with myocardial infiltration
  • Cardiac catheterization and myocardial biopsy are not often necessary. If done, catheterization detects high atrial pressure in RCM
  • CXR: pulmonary vascular congestion with normal heart size

TX: often unsatisfactory unless the cause can be addressed

  • Diuretics may benefit patients with edema or pulmonary vascular congestion but must be used cautiously to avoid lowering preload
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