CARDIOMYOPATHIES Flashcards
(56 cards)
Which type of cardiomyopathy is characterized by an ejection fraction of usually less than 30% when symptoms are severe?
A) Restrictive cardiomyopathy
B) Hypertrophic cardiomyopathy
C) Dilated cardiomyopathy
D) All of the above
Answer:
C) Dilated cardiomyopathy
Rationale: Dilated cardiomyopathy is associated with a significantly reduced ejection fraction, often below 30% in severe cases, due to impaired ventricular contraction.
Which type of cardiomyopathy is most commonly associated with markedly increased left ventricular wall thickness?
A) Restrictive cardiomyopathy
B) Hypertrophic cardiomyopathy
C) Dilated cardiomyopathy
D) None of the above
Answer:
B) Hypertrophic cardiomyopathy
Rationale: Hypertrophic cardiomyopathy is characterized by significant thickening of the left ventricular wall, often due to genetic mutations affecting sarcomere proteins.
Which cardiomyopathy subtype commonly presents with conduction disease, particularly in amyloidosis, but rarely with ventricular arrhythmias?
A) Dilated cardiomyopathy
B) Restrictive cardiomyopathy
C) Hypertrophic cardiomyopathy
D) None of the above
Answer:
B) Restrictive cardiomyopathy
Rationale: Conduction abnormalities are common in restrictive cardiomyopathy, particularly in conditions such as amyloidosis, whereas ventricular arrhythmias are uncommon.
Which cardiomyopathy subtype is often associated with exertional intolerance and can also present with chest pain?
A) Dilated cardiomyopathy
B) Restrictive cardiomyopathy
C) Hypertrophic cardiomyopathy
D) All of the above
Answer:
C) Hypertrophic cardiomyopathy
Rationale: Exertional intolerance is common across all three types, but hypertrophic cardiomyopathy is notably associated with chest pain, likely due to increased myocardial oxygen demand and microvascular dysfunction.
Which form of cardiomyopathy is most likely to present with right-sided congestion symptoms early in the disease course?
A) Dilated cardiomyopathy
B) Restrictive cardiomyopathy
C) Hypertrophic cardiomyopathy
D) None of the above
Answer:
B) Restrictive cardiomyopathy
Rationale: Restrictive cardiomyopathy frequently leads to early right-sided congestion symptoms due to impaired ventricular filling and increased atrial pressures.
Which of the following is the most common infectious cause of myocarditis?
A) Bacteria
B) Fungi
C) Viruses
D) Parasites
Answer:
C) Viruses
Rationale: Myocarditis has been reported with various infective agents, but it is most commonly associated with viruses and the protozoan Trypanosoma cruzi.
Which receptor on cardiac myocytes is particularly involved in viral myocarditis caused by coxsackieviruses and adenoviruses?
A) β-adrenergic receptor
B) Toll-like receptor
C) Coxsackie-adenovirus receptor
D) NMDA receptor
Answer:
C) Coxsackie-adenovirus receptor
Rationale: These viruses enter cells via the coxsackie-adenovirus receptor, which is prominently located around intercalated disks and the AV node.
What is the role of Toll-like receptors in viral myocarditis?
A) They directly degrade viral proteins.
B) They recognize common antigenic patterns and trigger an immune response.
C) They prevent viral replication within the myocardium.
D) They induce viral latency within cardiac myocytes.
Answer:
B) They recognize common antigenic patterns and trigger an immune response.
Rationale: Toll-like receptors are crucial in recognizing viral components and initiating an innate immune response, which is essential in the early phase of myocarditis.
What is a potential long-term consequence of ongoing cytokine release and immune activation in myocarditis?
A) Increased viral replication and clearance of infection
B) Myocyte hypertrophy without structural remodeling
C) Disruption of collagen and elastin scaffolding, leading to ventricular dilation
D) Increased cardiac contractility and resistance to infection
Answer:
C) Disruption of collagen and elastin scaffolding, leading to ventricular dilation
Rationale: Ongoing cytokine release activates matrix metalloproteinases, which degrade collagen and elastin, contributing to ventricular dilation and heart failure.
During the direct viral invasion phase of myocarditis, viruses typically enter the body through which routes?
A) Respiratory and gastrointestinal tracts
B) Bloodstream and lymphatic system
C) Skin and mucous membranes
D) Nervous system and cerebrospinal fluid
Answer:
A) Respiratory and gastrointestinal tracts
Rationale: Viruses gain entry through the respiratory or gastrointestinal tract before infecting organs that express specific receptors, such as the coxsackie-adenovirus receptor in the heart.
Which of the following is a common initial presentation of viral myocarditis?
A) Progressive dyspnea and weakness after a viral illness
B) Sudden-onset hypertension and bradycardia
C) Isolated peripheral edema without respiratory symptoms
D) Chronic, asymptomatic cardiomegaly
Answer:
A) Progressive dyspnea and weakness after a viral illness
Rationale: Viral myocarditis often presents days to weeks after a viral syndrome, with progressive dyspnea, weakness, fever, and myalgias.
Which of the following electrocardiographic (ECG) findings may be seen in a patient with viral myocarditis?
A) Changes suggestive of pericarditis or acute myocardial infarction
B) Only sinus tachycardia with no other abnormalities
C) Atrioventricular dissociation without other conduction defects
D) A completely normal ECG in all cases
Answer:
A) Changes suggestive of pericarditis or acute myocardial infarction
Rationale: Myocarditis can present with ST-segment elevations, PR-segment depressions (like pericarditis), or mimic myocardial infarction.
Which of the following statements best describes fulminant myocarditis?
A) It progresses over months with gradual onset of dyspnea.
B) It is a slow-onset disease that does not require urgent intervention.
C) It rapidly progresses within hours to cardiogenic shock and multiple organ failure.
D) It is always caused by bacterial infections.
Answer:
C) It rapidly progresses within hours to cardiogenic shock and multiple organ failure.
Rationale: Fulminant myocarditis develops rapidly and can lead to cardiogenic shock, renal failure, hepatic failure, and coagulopathy, often requiring mechanical circulatory support.
What is the primary role of cardiac magnetic resonance imaging (MRI) in diagnosing myocarditis?
A) To assess coronary artery stenosis
B) To evaluate myocardial edema and gadolinium enhancement
C) To measure pulmonary artery pressures
D) To determine left atrial volume
Answer:
B) To evaluate myocardial edema and gadolinium enhancement
Rationale: MRI with T2-weighted imaging and gadolinium enhancement helps detect myocardial inflammation, distinguishing myocarditis from other cardiac conditions
When is an endomyocardial biopsy recommended in the evaluation of myocarditis?
A) In all cases of suspected viral myocarditis
B) When heart failure is accompanied by conduction blocks or ventricular arrhythmias
C) Only when cardiac MRI findings are inconclusive
D) Only when blood cultures confirm an infectious etiology
Answer:
B) When heart failure is accompanied by conduction blocks or ventricular arrhythmias
Rationale: Biopsy is indicated in cases where noninfectious inflammatory causes (e.g., sarcoidosis or giant cell myocarditis) are suspected, which may require immunosuppressive therapy.
What distinguishes definite myocarditis from probable myocarditis?
A) Presence of a viral syndrome with elevated cardiac biomarkers
B) Clinical symptoms of heart failure
C) Histologic or immunohistologic evidence of inflammation on biopsy
D) MRI findings suggestive of myocardial edema
Answer:
C) Histologic or immunohistologic evidence of inflammation on biopsy
Rationale: Definite myocarditis requires biopsy-proven inflammation, whereas probable myocarditis is diagnosed based on clinical presentation and imaging findings.
Which of the following best describes possible subclinical acute myocarditis?
A) Presence of cardiac symptoms along with abnormal ECG and biomarkers
B) No cardiac symptoms but with elevated cardiac biomarkers or abnormal ECG findings
C) Histologic or immunohistologic evidence of myocarditis
D) Presence of pericardial effusion without other findings
Answer:
B) No cardiac symptoms but with elevated cardiac biomarkers or abnormal ECG findings
Rationale: Possible subclinical acute myocarditis is diagnosed when a patient has a viral syndrome but no cardiac symptoms, yet shows biomarker elevation, abnormal ECG, or left ventricular dysfunction.
Which clinical feature differentiates probable acute myocarditis from possible subclinical acute myocarditis?
A) Presence of pericardial effusion
B) Histologic confirmation on biopsy
C) Presence of cardiac symptoms (e.g., chest pain, dyspnea)
D) MRI findings of myocardial fibrosis
Answer:
C) Presence of cardiac symptoms (e.g., chest pain, dyspnea)
Rationale: Probable acute myocarditis includes all features of possible myocarditis but also involves clinical symptoms such as dyspnea or chest pain.
What is the defining criterion for definite myocarditis?
A) Abnormal ECG and elevated cardiac biomarkers
B) Positive cardiac MRI findings
C) Histologic or immunohistologic evidence of myocardial inflammation on biopsy
D) Clinical symptoms of heart failure
Answer:
C) Histologic or immunohistologic evidence of myocardial inflammation on biopsy
Rationale: Definite myocarditis requires biopsy-confirmed inflammation, whereas probable myocarditis relies on clinical and imaging findings.
A patient presents with chest pain and shortness of breath after a recent viral illness. ECG shows ST-segment changes, and troponin is elevated. What is the most appropriate classification?
A) Possible subclinical acute myocarditis
B) Probable acute myocarditis
C) Definite myocarditis
D) Chronic myocarditis
Answer:
B) Probable acute myocarditis
Rationale: The presence of cardiac symptoms (chest pain, dyspnea) alongside ECG and biomarker abnormalities meets the criteria for probable acute myocarditis.
When does Peripartum Cardiomyopathy (PPCM) typically develop?
A) During the first trimester of pregnancy
B) Only after delivery
C) During the last trimester or within the first 6 months postpartum
D) At any point before conception
Answer:
✅ C) During the last trimester or within the first 6 months postpartum
Rationale: PPCM occurs late in pregnancy or after delivery, making it distinct from other pregnancy-related heart conditions. It is not diagnosed before the last trimester.
Which of the following is NOT a known risk factor for PPCM?
A) Twin pregnancy
B) Increased maternal age
C) Gestational diabetes
D) Preeclampsia
Answer:
✅ C) Gestational diabetes
Rationale: While preeclampsia, multiple pregnancies, older maternal age, and high parity are known risk factors, gestational diabetes is not directly associated with PPCM.
Which of the following therapies is currently being investigated for PPCM based on its proposed mechanisms?
A) Bromocriptine
B) Aspirin
C) Statins
D) Beta-blockers only
Answer:
✅ A) Bromocriptine
Rationale: Bromocriptine inhibits prolactin secretion, which has been implicated in PPCM pathogenesis. This therapy is still under investigation but shows potential for angiogenic balance restoration.
Which genetic mutation is found in about 15% of PPCM cases, suggesting a genetic link to dilated cardiomyopathy (DCM)?
A) MYH7
B) TTN
C) LMNA
D) DSP
Answer:
✅ B) TTN
Rationale: Truncating mutations in TTN (Titin gene) are seen in familial and sporadic DCM and have also been found in PPCM cases, suggesting a genetic predisposition in some patients.