HLSC 3P90 Lecture Notes - Lecture 16: Hypertrophic Cardiomyopathy, Left Ventricular Hypertrophy, Dilated Cardiomyopathy
15 Dec 2019
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Document Summary
Heart disorder in which major abnormality is related to the myocardium. These do not include diseases of heart muscle impairment: valvular heart disease, coronary artery disease, hypertension, etc, etiology usually remains unknown. Marked enlargement of all four chambers: can be limited to the right or left side of the heart. Chamber dilation is out of proportion to a concentric hypertrophy. Evidence of myocyte degeneration with irregular hypertrophy and atrophy of myofibers. Initial compensatory mechanisms: frank-starling elevated ventricular diastolic volume increases the stretch of myofibers, resulting in an increase in sv, neurohormonal activation sns hr & contractility increase to maintain co. These mechanisms may render patient as asymptomatic in early stages. However, progressive myocyte degeneration and volume overload = persistent reduction in co results in a decline of renal blood flow. Renin release activation of renin-angiotensin-aldosterone axis vasoconstriction (ang ii) and increased intravascular volume (aldosterone) to maintain bp. Vasoconstriction and increased resistance make it more difficult to eject blood.
