Download Clarifications from Valvular Heart Disease Lecture

Definition:
Hypertrophy: Enlargement or overgrowth of an organ or part of the body due to the increased size of
the constituent cells. Hypertrophy occurs in the biceps and heart because of increased work.
Cardiachypertrophy is recognizable microscopically by the increased size of the cells.
Dilatation: The process of enlargement or expansion. The word "dilation" means the same thing as
"dilatation". Both come from the Latin "dilatare" meaning "to enlarge or expand."
Characterized by increased ventricular volumes without a proportionate increase in ventricular
wall thickness
Mitral Valve Stenosis results in:
 Incomplete emptying of Left Atrium (LA) Increased LA pressure LA dilatation
and hypertrophy
 Increased LA pressureElevated pulmonary pressurepulmonary congestion
***sparing effect on left ventricle
Mitral Valve Regurgitation (insufficiency): - inadequate closure of mitral valve
Acute Onset (e.g. papillary dysfunction due to M.I.)
 Backward flow from left ventricle to left atria  increased LA pressure  Increased
Pulmonary Pressure  Pulmonary Edema
Chronic Onset
 Backward flow  LA dilates (progressively) and hypertrophies (mildly) 
Increased pulmonary pressures  pulmonary congestion  right sided failure
***in chronic mitral valve regurgitation, volume overload on the left ventricle, the left
atrium and the pulmonary bed is created by the backward flow of blood from LV to LA
during ventricular systole resulting in various degrees of left atrial enlargement and left
ventricular dilatation (to accommodate for regurgitant volume)
Aortic Valve Stenosis:
 Results in obstruction of flow from LV to aorta during systole
 Effect is left ventricular hypertrophy and increased myocardial oxygen consumption
because of increased myocardial mass
Aortic Valve Regurgitation:
 Retrograde blood flow from ascending aorta to left ventricle
 Elevated LV pressures
 LV dilatation and hypertrophy