angina and treatments Flashcards
what is angina
when oxygen supply to the myocardium is insufficient
symptoms of angina
retrosternal cardiac pain
may radiate to arms, neck, jaw
difficult to distinguish from heart burn
treatment aims for angina
reduce cardiac workload
reduce pre-load
reduce after load
reduce cardiac rate/contractility
improve efficiency of the heart
how can cardiac workload be reduced
rest, reduce smoking, stress and weight
how can pre load be reduced
Venodilator - nitrates
how can after load be reduced
arterial dilator - CCBs Bblockers
how can cardiac rate and contractility be reduced
beta blockers and CCBs
how can the efficiency of the heart be improved
exercise
no smoking
what are nitrates and how do they work
GTN - releases Nitrous oxide which relaxes smooth muscle
effects of nitrates at low doses
large vein dilation
Central venous pressure reduction (Pre-load)
Cardiac output and oxygen consumption reduced
effects of nitrates at high doses
Arteriolar dilation
BP falls
Reduced CO
Headache
how does NO cause smooth muscle relaxation
Activates guanylyl cyclase - activates kinases which dephosphorylate myosin light chain = vasodilation
what are the three types of calcium channel blockers
- Phenylalkylamines - verapamil - cardio selective
- Dihydropyridines - amlodipine
- Benzothiazepines - diltiazem
how do CCBs work in the treatment of angina
Block calcium ions entering the cell through blocking voltage gated L-type calcium channels (A1 subunit)
which CCB is C/I in HF
verapamil
