prep4usmle
Administrator
Topics: 288
Posts: 1,187
|
Aortic stenosis is a fixed mechanical obstruction to cardiac output.
Nifedipine decreases the afterload but the cardiac output cannot increase (fixed flow impedance across the aortic valve).
The result will be a decrease in the blood presure, possible heart failure.
___________________
••• Support our forum » Upgrade to premium membership!
|
| daira
Forum Senior
Topics: 29
Posts: 138
|
Just to add:
Nifedipine blocks L-type Ca channels in vascular smooth muscles, hence causing vasodilation. It has no effect on heart. Other Ca antagonists (Diltiazem and Verapamil) has greater activity on heart.
In AS Nifedipine will cause vasodilation, leading to reflex tachycardia, which will result in further decrease in blood flow through the stenotic valve.
___________________
Roz barhta hoon jahan se aagey
lout kar phir waheen aa jata hoon
baaraha tor chuka hoon jinko
phir unhin dewaroon se takrata hoon...
|
|
| |
| | |
