Cardiac Pathology Flashcards
What is the adverse effect of taking verapamil and a beta blocker together?
Dangerous bradycardia
What is hypertrophic cardiomyopathy?
Variable hypertrophy in distribution and extent of LV/both ventricles
What are the morphological features of hypertrophic cardiomyopathy?
Myocyte hypertrophy and disarray
Interstitial fibrosis
Thickened intima of small intramyocardial arteries
What are the different pathophysiologies of hypertrophic cardiomyopathy?
Impaired ventricular compliance > diastolic failure
Impaired LV outflow
Ischaemia from increased muscle mass and abnormal intramyocardial arteries +/- increased wall stress related to outflow obstruction
What is the clinical picture of hypertrophic cardiomyopathy?
Asymptomatic Due to ischaemia +/- increased wall stress - Arrhythmias - Angina - Heart failure Due to abnormal myofibres - Arrhythmias
When does hypertrophic cardiomyopathy usually present?
Before 4th decade
What is the aetiology of hypertrophic cardiomyopathy?
Genetic
- Autosomal dominant
- Mutations in genes encoding sarcomeric proteins
Where do watershed infarcts occur?
Borders between cerebral vascular territories > little-no anastamoses
What are the two different types of acute tubular necrosis?
Ischaemic
Nephrotoxic
What pathology happens in shock to the major organs?
Acute myocardial ischaemia > subendocardial necrosis
Kidney - acute tubular necrosis
Liver - centrilobular necrosis
Acute respiratory distress syndrome/diffuse alveolar damage
What is the most common type of cardiomyopathy?
Idiopathic dilated cardiomyopathy
What does idiopathic dilated cardiomyopathy do?
Dilation and impaired contraction of LV/both ventricles
Often also affects atria
What is the morphology of idiopathic dilated cardiomyopathy?
Eccentric hypertrophy of LV +/- RV
Myocyte hypertrophy
Interstitial and endocardial fibrosis
When does idiopathic dilated cardiomyopathy often become apparent?
3rd-4th decade of life
What are the clinical features of idiopathic dilated cardiomyopathy?
Deteriorating biventricular failure Arrhythmias - Sudden death Thromboembolic complications Steady course +/- improvement
What is the aetiology of idiopathic dilated cardiomyopathy?
Genetic Possible factors - Viral - Toxic - Autoimmune
What are some conditions in which dilated cardiomyopathy can occur?
Peripartum period Haemochromatosis Alcohol Certain drugs Ischaemia Some neuromusuclar diseases; eg: Duchenne's muscular dystrophy
What is restrictive cardiomyopathy?
Rigid but not necessarily thickened ventricles
Impaired diastolic filling > failure
What is restrictive cardiomyopathy related to?
Fibrosis of endomyocardium
Infiltration of myocardium; eg: amyloid in primary/secondary/senile amyloidosis
What is arrhythmogenic right ventricular cardiomyopathy?
Replacement of cardiomyocytes by fibro-fatty tissue
Serious arrhythmias
Sudden death
What is the aetiology of arrhythmogenic right ventricular cardiomyopathy?
Autosomal dominant
Variable penetrance
What is myocarditis?
Inflammation and necrosis/degeneration of myocytes
What are the causes of myocarditis?
Infection Sarcoidosis Giant cell myocarditis Acute rheumatic fever Toxic Drugs Transplant rejection
What viruses can cause myocarditis?
Coxsackie
Echoviruses
What protozoans can cause myocarditis?
Chaga’s disease
Toxoplasma
What causes toxic myocarditis?
Diphtheria
How can drugs cause myocarditis?
Hypersensitivity
Cardiotoxic
What is the most common type of myocarditis?
Viral
What is the microscopic appearance of viral myocarditis?
Patchy mononuclear infiltrate
Myocardial necrosis
What is the macroscopic appearance of viral myocarditis?
Mottled/dilated/normal
What are the clinical features of viral myocarditis?
Asymptomatic Flu-like illness Chest pain Syncope Rapid onset heart failure Arrhythmias Sudden death
What are the outcomes of viral myocarditis?
Resolution
Rapid deterioration
Slow progression to dilated cardiomyopathy
What are the complications of cardiac sarcoid?
Arrhythmias
Heart failure
Sudden death
What is sudden death?
Unexpected fatal event within 1 hour of beginning of symptoms/without symptoms in apparently healthy subject/not severe disease
What is the pathophysiology of ventricular tachyarrhythmias?
Automaticity of diseased ventricular myocytes
Wave propagation of ventricular impulse interrupted by diseased muscle > intraventricular re-entry
Abnormalities of repolarisation
What are some causes of sudden cardiac death in young people due to coronary artery disease?
Congenital coronary artery anomalies Vasculitis Coronary emboli Spontaneous dissection Atherosclerosis
What are some causes of sudden cardiac death in young people due to the myocardium?
Hypertrophic cardiomyopathy Dilated cardiomyopathy Arrhythmogenic cardiomyopathy Myocarditis LVH of >50% by mass
What are some causes of sudden cardiac death in young people due to morphological conduction pathways?
Wolf-Parkinson-White disease
Sarcoidosis
Autoimmune associated inflammation; eg: ankylosing spondylitis
What are some causes of sudden cardiac death in young people due to valves?
Congenital aortic stenosis > LVH
Floppy/myxomatous mitral valve
What are some causes of sudden cardiac death in young people that are acquired?
Thiuzides Macrolides Methodone Halperidol Selective reuptake inhibitors Antihistamines Hypothyroidism Hypocalcaemia Cocaine
What can cause an aortic rupture?
Dissection
Infection
How can aortic dissection cause death?
Haemopericardium > tamponade
Coronary artery narrowing > myocardial ischaemia/infarction
Rupture > hypovolaemia
Acute aortic valve incompetence
