30 terms

Mitral and Aortic Stenosis

stenotic lesions cause _________ overload
regurgitant lesions cause _________ overload
coronary stenotic lesions: avoid ______ and ______
AVOID increased heart rate and decreased SVR
normal mitral valve area
4-6 sq. cm.
surgical mitral stenosis area
less than 1 sq cm
surgical mitral valve pressure graident
greater than 10 mm Hg
normal aortic valve area
2.5-3.5 sq cm
surgical aortic stenosis area
less than 0.75 sq cm
surgical aortic pressure gradient
greater than 50 mm Hg
mitral stenosis leads to fixed ____ and increased _____
FIXED cardiac output, INCREASED pulmonary pressures
if left untreated, mitral stenosis can lead to
pulmonary edema and RV failure
most common cause of mitral stenosis
rheumatic carditis
what cardiac rhythm often accompanies mitral stenosis? (why?)
atrial fibrillation; chronic increased back pressure causes atrial dilatation
are digitalis levels necessary prior to surgery in setting of atrial fibrillation?
no; goal is rate control rather than drug level
why avoid tachycardia in stenotic valvular disease?
tachycardia severely reduces cardiac output; limits diastolic filling of left ventricle; decreases diastolic corony perfusion time
normal atrial kick contribution
20% of CO
atrial kick contribution in mitral stenosis
35% of CO
reason to avoid isoflurane in setting of mitral stenosis
decreases SVR and increases HR
first two steps in management if SVT develops in setting of mitral stenosis
1) digitalis. if fails, then 2) DC-cardioversion
symptoms of aortic stenosis
syncope, angina, dyspnea-CHF
why avoid decreased SVR in stenotic valvular disease?
compromises aortic diastolic blood pressure and coronary perfusion pressure
survival expectancy in patient with AS presenting with angina
5 years
survival expectancy in patient with AS presenting with CHF
3 years
survival expectancy in patient with AS presenting with syncope
1 year
most common cause of isolated aortic stenosis
congenital bicuspid valve
how does heart maintain forward flow in setting of aortic stenosis?
LV systolic pressure increases with an increase in wall tension; compensatory response is concentric ventricular hypertrophy
Hemodynamic goal in aortic stenosis: preload
keep it full; patient must have adequate volume to fill noncompliant ventricle
Hemodynamic goal in aortic stenosis: afterload
don't decrease systemic vascular resistance
Hemodynamic goal in aortic stenosis: rate
don't allow tachycardia. it will lead to poor filling and ischemia
long standing atrial fibrillation: necessary to cardiovert before surgery?
no; may actually increase risk of embolism