Cardiomyopathy Lecture Notes

Overview

• Types of Cardiomyopathy: Dilated, Restrictive, and Hypertrophic.
• Importance: Significant portion of PANCE exam.

Heart Failure Refresher

• Systolic Heart Failure:
  • Ventricles are thin, weak, overly compliant.
  • Decreased ejection fraction.
  • Auscultation: S3 gallop.
• Diastolic Heart Failure:
  • Ventricles are stiff, thick, non-compliant.
  • Normal ejection fraction.
  • Auscultation: S4 gallop.
• Left vs. Right-Sided Heart Failure:
  • Left-Sided: Blood backs up into lungs causing pulmonary symptoms (dyspnea, congestion). Mnemonic: L for Lungs.
  • Right-Sided: Blood backs up into body causing systemic symptoms (edema, JVD, hepatic congestion). Mnemonic: R for Rest of body.

Dilated Cardiomyopathy

• Characteristics: Dilated, baggy ventricles leading to impaired contraction.
• Most Common Type: 90-95% of cardiomyopathy cases.
• Etiologies:
  • Most common: Idiopathic (50%).
  • Others: Alcohol, cocaine, doxorubicin, viral infections, vitamin B1 deficiency.
  • Mnemonic: 6 D's (Drinking, Don't know, Deficiency, Doxorubicin, Drugs, Disease).
• Manifestations: Systolic heart failure symptoms, both left and right-sided.
• Diagnosis:
  • Echocardiogram: Ventricular dilation, thin walls, decreased ejection fraction.
  • X-ray: Cardiomegaly, pleural effusion.
  • EKG: Arrhythmias, sinus tachycardia.
• Treatment:
  • Reduce mortality: ACE inhibitors, beta-blockers, hydralazine+nitrates, spironolactone.
  • Symptom control: Loop diuretics, digoxin.
  • Mnemonic: BASH (Beta-blockers, ACE inhibitors, Spironolactone, Hydralazine+Nitrates).
  • Severe cases: ICD (Implantable Cardiac Defibrillator).

Restrictive Cardiomyopathy

• Characteristics: Stiff ventricles due to infiltrative diseases leading to diastolic dysfunction.
• Rarity: Only 1% of cases.
• Etiologies: Amyloidosis, hemochromatosis, sarcoidosis. Mnemonic: Amy HAS restrictive cardiomyopathy (Amyloidosis, Hemochromatosis, Amyloidosis, Sarcoidosis).
• Manifestations: More right-sided heart failure symptoms (hepatomegaly, JVD, peripheral edema).
• Diagnosis:
  • Echo: Normal/thickened ventricles, diastolic dysfunction, atrial dilation.
  • Definitive: Endomyocardial biopsy shows amyloidosis (apple green birefringence).
• Treatment: Treat underlying cause, use beta-blockers, calcium channel blockers, loop diuretics for symptom control.

Hypertrophic Cardiomyopathy

• Characteristics: Genetic disorder leading to hypertrophy of the left ventricle/septum causing outflow obstruction.
• Symptoms: Range from asymptomatic to sudden cardiac death. Dyspnea, angina, fatigue, syncope.
• Physical Exam:
  • Harsh systolic murmur best heard at the left sternal border.
  • Increases with decreased venous return.
• Diagnosis:
  • Echo: LV wall 15mm or more, or 13mm with family history.
  • EKG: Not very specific but can show repo changes, left axis deviation.
• Treatment:
  • Beta-blockers or non-dihydropyridine calcium channel blockers (slow heart rate, increase filling).
  • Invasive: Septal myomectomy or alcohol septal ablation.
  • Avoid: Digoxin, nitrates, diuretics, exertion, dehydration.
• Key Points: Autosomal dominant disorder, harsh systolic murmur, beta-blockers as first-line treatment.

Test Your Knowledge

• Common Type of Cardiomyopathy: Dilated.
• Mortality-Reducing Meds for Heart Failure: BASH (Beta-blockers, ACE Inhibitors, Spironolactone, Hydralazine+Nitrates).
• Common Cause of Restrictive Cardiomyopathy: Amyloidosis (Amy HAS mnemonic).
• Kussmaul's Sign: Increased JVP with inspiration.
• First-Line Treatment for Hypertrophic Cardiomyopathy: Beta-blockers.

These notes cover the primary points about cardiomyopathy, preparing you for exams and clinical practice.