cardiovascular pathology Flashcards
cardiomyopathy: recall the types, investigations, and treatment of cardiomyopathy
what is the law of LaPlace
wall stress = (transmural pressure x radius)/(2 x wall thickness)
effect of increasing thickness on wall stress
reduces wall stress
what is compensatory hypertrophy
reduction in wall stress in response to acute load, as ventricular cells undergo hypertrophy
what does compensatory hypertrophy lead to
dilated cardiomyopathy as ventricle volume reduced, increasing wall stress - thin wall can no longer contract with enough force to eject blood
define cardiomyopathy
heart muscle disease where walls are stretched, thickened or stiff
what is dilated cardiomyopathy
walls become stretched and thin so can’t contract effectively, causing risk of heart failure and valve problems
what is hypertrophic cardiomyopathy
walls become enlarged so chambers reduced in size; walls cannot properly relax
what is restrictive cardiomyopathy
ventricle walls stiffened and cannot relax, so filling impaired, causing heart failure
what is arrhythmogenic right ventricular cardiomyopathy
proteins holding myocytes together are abnormal, leading to death and replacement with fat or fibrous tissue
what is takotsubo (broken heart syndrome)
emotional stress can stun left ventricle, so cannot contract effectively
diagnosis of cardiomyopathy
ECG, echocardiogram
treatments of cardiomyopathy
no cure but lifestyle changes, diuretics, B-blockers and anticoagulants used
beneficial physiological response of BNP release when myocytes stretched
causes vasodilation, reduced aldosterone, reduced BP
pathological response of BNP release when myocytes stretched
reduced renal perfusion leads to activation of RAAS, leading to aldosterone production, vasoconstriction, sodium and water retention, and increased blood pressure
