Cardiovascular - NICOLE Flashcards
heart failure is
the inability of the heart to meet the metabolic needs of the peripheral tissues
pathophysiology of heart failure
-pump failure
- forward obstruction to blood flow
- regurgitant blood flow
-congenital shunts
- rupture of heart of vessels
- conduction disorders
decreased cardiac output leads to activation of what
sympathetic activation (a,B)
short and long term responses to underlying cardiovascular disease
increase heart rate
increase peripheral resistance
increase blood volume
redistribute blood flow
cardiac dilation
myocardial hypertrophy
pharmacological modification of cardiac function is usually achieved by modifying one or more of the following
chronotropy (heart rate)
inotropy (contractility)
peripheral resistance (vascular tone)
blood volume (diuresis, fluids)
rate of conduction (rhythm)
neurohormonal input to the heart
name some things you want to change with drugs?
preload, afterload, rate/rhythm, contractility, sympathetic/neurohormonal input
Frank-Starling Law - Cardiac output increases with ________ and decreases with _______
exercise, disease
the cardiac output of the diseased heart is reduced at any ________
preload
changes in preload have less of an effect on the output of the __________than on the output of the healthy heart
diseased heart
neurohormonal activation and excessive sodium and water retention leads to
elevated intracardiac and venous pressure (backward failure). Intravenous pressures >25 mg Hg results in signs of congestion
Diuretics move performances leftward along the Frank-Starling by reducing
preload and moving performances to a position below the threshold for congestion. Diuretics have little effect on cardiac output
cardiac injury can also result in low cardiac output (forward failure). What helps with this?
positive inotropes improve cardiac contractility, which improves output at any preload
patients with severe heart failure can exhibit signs of poor cardiac output and congestion (forward and backward failure). These patients require
positive inotropes and diuretics to shift the curve/improve function
The Frank-Starling Law states that the stroke volume of cardiac contraction ______________ as preload increases
increases
Inotropes - what mechanism/drugs
adrenergic drugs, inodilators, cardiac glycosides
chronotropes - what mechanisms/drugs
adrenergic drugs
cholinergic drugs
antiarrthymics - what classes
class 1 - sodium channel blockers
class 2 - beta blockers
class 3 - potassium channel blockers
class 4 - calcium channel blockers
positive inotropes
increase contractility
negative inotropes
decrease contractility
positive inotropes are useful in clinical situations when
decreased cardiac output is due to decreased myocardial contractility - ex dilated cardiomyopathy
negative inotropes have limited usefulness as a
first-line therapy but can be useful to allow cardiac relaxation and filling in hypertrophic cardiomyopathy. They also decrease cardiac oxygen consumption
when skeletal muscle contracts the calcium released by the SR is sufficient to
interact with all of the troponin, causing ALL potential actin-myosin interactions to occur
in cardiac muscle, NOT ALL troponin interacts with
calcium; thus, more or fewer actin-myosin cross bridges may form depending on intracellular calcium availability
WHATEVER CONTROLS THE CALCIUM WILL CONTROL
Cardiac contractility