The renin-angiotensin agents are very
important in both chronic heart failure
and in acute management of high blood pressure.
We know that these agents reduce
morbidity and mortality in heart failure.
They reduce aldosterone
secretion and water retention
and they also reduce total peripheral
resistance or vascular resistance
through its antihypertensive effects.
I've listed here all of the ACE
inhibitors, and here are all of the ARBs.
Now the angiotensin receptor blockers have been in
studies shown to be non-inferior to ACE inhibitors.
You'll generally find on the wards
that cardiologist favor ACE inhibitors
and the ARBs are favored by everyone else.
I don't think there's really a
right answer in ACE versus ARB.
The direct renin inhibitors such as
aliskiren, are relatively new medications
that are not currently recommended
in the treatment of heart failure.
Let's move on to the beta blockers.
Remember that in heart failure we only use
beta blockers once the patient has been stabilized.
Beta-blockers may actually be harmful in acute heart
failure because it may suppress cardiac function.
Beta blockers work by two major ways.
First of all, they reduce heart rate
and increase the stroke volume.
That's because when you reduce
heart rate, the heart has more time to fill
and as it has more time to fill, each stroke
will become more efficient and powerful.
It also reduces overall mortality and
progression of chronic heart failure.
Carvedilol is the favorite
beta blocker in heart failure.
Major studies have shown
reduction of morbidity and mortality.
Carvedilol has all alpha, beta, and beta-2 effects,
so it's a very effective agent and
it's very well-tolerated in heart failure.
Evidence-based medicine has
shown us that when treating heart failure
with reduced ejection fraction, we
should use one of three beta blockers
that have been shown to reduce mortality -
bisoprolol, carvedilol and
sustained release metoprolol.