DILATED CARDIOMYOPATHY Flashcards
What is the definition of heart failure (HF)?
HF is a clinical syndrome resulting from progressive myocardial dysfunction that compromises ventricular filling and cardiac output.
What are the categories of heart failure based on left ventricular ejection fraction (LVEF)?
- HF with preserved ejection fraction (HFpEF): LVEF > 50%-55%
- HF with reduced ejection fraction (HFrEF): LVEF < 40%
- HF with mid-range ejection fraction (HFmEF): LVEF 41%-49%
What is the lifetime risk of developing heart failure?
Approximately 20%.
What is the prognosis for heart failure patients within 5 years of diagnosis?
Absolute mortality remains high at 50%.
What is the major pathophysiology of HFrEF?
A primary insult to the myocardium leads to depression in LV systolic function and decreased systemic blood flow, activating neurohormonal responses that cause adverse cardiac remodeling.
What is dilated cardiomyopathy (DCM)?
DCM is a term describing myocardial dysfunction with progressive LV wall thinning and dilation and reduced LVEF in the absence of abnormal loading conditions.
What are common causes of dilated cardiomyopathy?
- Genetic causes
- Toxins
- Infection
- Inflammatory disorders
- Nutritional disorders
- Pregnancy
- Endocrine disorders
- Tachycardia-induced cardiomyopathy
- Stress-induced cardiomyopathy
What are typical presenting symptoms of DCM?
- Exertional dyspnea
- Fatigue
- Reduced exercise tolerance
- Weakness
- Orthopnea
- Paroxysmal nocturnal dyspnea
- Weight gain
- Early satiety
- Nausea
- Bendopnea
- Lower extremity edema
What key physical examination findings are associated with DCM?
- Elevated jugular vein pressure (JVP)
- Extra heart sounds (S3, S4)
- Pulmonary congestion
- Lower extremity edema
What diagnostic tests are part of the initial evaluation for DCM?
- Complete blood count
- Comprehensive metabolic panel
- Fasting lipid profile
- Urinalysis
- Thyroid-stimulating hormone (TSH)
- Natriuretic peptide levels
- Cardiac enzymes
- Chest radiograph
- Electrocardiogram (ECG)
- Echocardiography
What is the role of transthoracic echocardiography (TTE) in diagnosing LV dysfunction?
TTE quantifies LVEF and provides prognostic information on LV dilation, chamber geometry, wall motion abnormalities, and right ventricular assessment.
What advanced imaging technique is considered the gold standard for assessing biventricular EF?
Cardiac magnetic resonance imaging (CMRI).
Do all patients with new LV dysfunction or DCM require an ischemic evaluation?
True, especially if experiencing angina symptoms or having CAD risk factors.
What are the advantages of using cardiac MRI?
- Superior assessment of myocardial viability
- Diagnostic value for infiltrative cardiomyopathies
- Noninvasive with no radiation exposure
What are the disadvantages of using cardiac MRI?
- Gadolinium contraindicated in certain kidney conditions
- Limited availability
- Expensive and time-consuming
Fill in the blank: Heart failure patients are categorized based on their _______.
[left ventricular ejection fraction (LVEF)]
What is the role of endomyocardial biopsy (EMB) in the diagnosis of LV dysfunction?
EMB is not commonly indicated for newly diagnosed HF and should only be performed in specific clinical circumstances. Class 1 recommendations include:
* Unexplained acute HF with hemodynamic compromise
* New HF with dilated LV and new ventricular arrhythmias/high-degree AV block, or failure to respond to standard care.
EMB results may often be nonspecific or unrevealing in DCM.
What is the significance of right heart catheterization (RHC) in patients with newly diagnosed and chronic DCM?
RHC may provide critical hemodynamic information in acute decompensated HF, especially with:
* Progressive dyspnea
* Poor perfusion
* Worsening end-organ function
* Poor response to medical therapy.
RHC also assesses pulmonary hypertension severity.
What are the most commonly studied biomarkers in heart failure (HF)?
BNP and NT-proBNP are the most studied biomarkers in HF.
Elevated BNP indicates worse clinical outcomes, while a decrease with therapy suggests improved outcomes.
What is the relationship between genetic factors and dilated cardiomyopathy (DCM)?
25% to 30% of DCM cases are familial. Common genetic mutations include:
* Sarcomere proteins
* Cytoskeletal proteins
* Calcium handling proteins
* Nuclear membrane proteins.
The most common genetic abnormality involves mutations encoding the sarcomere protein titin (TTN).
What characterizes stress-induced or Takotsubo’s cardiomyopathy?
Takotsubo’s is characterized by:
* Acute LV dysfunction
* Emotional or physical stress
* Chest pain, shortness of breath
* ECG changes (T-wave inversions, ST elevation)
* Apical akinesis with basal hyperkinesis.
Recovery of LVEF usually occurs within 1 to 2 weeks.
What are the features of toxin-mediated cardiomyopathy?
Alcohol is a direct cardiomyocyte toxin leading to DCM with chronic use. Other toxic substances include:
* Cocaine
* Amphetamines
* Clozapine
* Hydroxychloroquine
* Cobalt
* Lead.
Alcohol abstinence can partially or completely reverse DCM.
What defines chemotherapy-induced cardiomyopathy?
Defined as LVEF reduction of at least 5% (symptomatic HF) or 10% (asymptomatic HF) to LVEF <50%. Most prominent agents include:
* Anthracyclines
* Trastuzumab.
Anthracyclines can cause cardiotoxicity early or 10 to 20 years post-therapy.
What are the features of peripartum cardiomyopathy (PPCM)?
PPCM occurs in the last trimester or within 6 months postpartum. Risk factors include:
* African American race
* Preeclampsia
* Hypertension
* Multigestational pregnancy
* Older maternal age.
Treatment includes beta-blockers and anticoagulation due to higher thromboembolism incidence.
