Heart failure Flashcards
what is heart failure?
the inability of the ventricles to pump enough blood to meet the body’s metabolic demands.
- inadequate circulatory volume & pressure
- results in inadequate perfusion of tissues
what are some disorder that cause heart failure?
- mitral stenosis
- myocardial infraction (MI)
- chronic hypertension
- coronary artery disease (CAD)
- diabetes mellitus
what are non pharmacological ways heart failure can be reduce?
- controlling lipid levels
- implementing a regular exercise program
- maintaining optimum body weight
- keeping blood pressure w/in recommended limits =reduces CAD and MI
- HF is a PREVENTABLE condition
- control salt intake
what is the right side of the heart responsible for?
-the right side of the heart receives blood from the venous system and pumps it to the lungs, where the blood receives oxygen and loses it carbon dioxide
what is the left side of the heart responsible for?
the right side return the blood to the left side of the heart, which pumps it to the rest of the body via the aorta
-the amount of blood received by the right side should exactly equal that sent out by the left side
what is cardiac output?
the amount of blood pumped by each ventricle PER min
what is preload?
the degree to which the myocardial fibres are stretched just prior to contraction
what is Frank-Starling law?
the greater the degree of stretch on the myocardial fibres, the greater will be the force by which they contract
-think of a rubber band- the more it is stretched, the more forcefully it will snap back
-BUT…as preload continues to rise it causes repeated stretching of myocardium
doesn’t snap back as forcefully
contractility & thus CO is decreased
=HF worsens
what is contractility?
the strength of contraction of the heart
what are drugs that increase contractility? (called positive inotropic agents)
-norepinephrine, epinephrine, and thyroid hormones
what are drugs that decrease contractility? (called negative inotropic agents)
drugs such as beta-adrenergic blockers
what is after load?
the pressure in the aorta that must be overcome for blood to be ejected form the left ventricle
what happens in left sided heart failure? (sometimes congestive HF)
excess blood accumulates in the left-ventricle
- the wall of the left ventricle may become thicker (hypertrophies) in attempt to compensate for the extra blood retained in the chamber
- since the left ventricle has limits to its ability to compensate for the increased preload, blood “backs up” into the lungs, resulting in S/S of SOB, crackles etc.
- LHF is most common
what happens in RHF?
the blood backs up into the peripheral veins, resulting in peripheral edema and engorgement of organs such as the liver
what are the most common S/S of HF?
- dyspnea
- orthopnea
- paroxysmal nocturnal
- fatigue
- weakness
- exercise intolerance
- dependent edema
- cough
- weight gain
- abdominal distention
- nocturia
- cool extremities
what are some less common S/S of HF?
- cognitive impairment
- altered mentation or delirium
- nausea
- abdominal discomfort
- oliguria
- anorexia
- cyanosis
what are natriuretic peptides?
are substances secreted in response to increased pressure in the heart
- atrial NP is secreted by the atria
- B-type NP- is secreted by the cardiac ventricles
- C-type NP is secreted by the brain
what do ANP and BNP do?
they are secreted in response to the left ventricular volume overload and dysfunction
-they cause dieresis and reverse the negative effects of sympathetic nervous system and the renin-angiotensin aldosterone system activation on the heart
BNP is used
as a biomarker to diagnosis and establish the severity of HF
all pts w/ left ventricle that ejects less than 40% should
be treated w/ triple therapy either ACE or ARB, a beta blocker, and mineralocorticoids receptor antagonist (MRA)
what type of med would you give a pt w/ peripheral edema or pulmonary congestion?
diuretics
what are the primary pharmacotherapy goals of Hf?
- reduction of preload
- reduction of systemic vascular resistance (afterload reduction)
- inhibition of both the renin-angiotensin aldosterone system (RASS) and the vasoconstrictor mechanisms of the SNS
when should ACE inhibitors be discontinued?
-if pt is experiencing angioedema (ex. facial swelling or difficultly breathing)
how do ACE inhibitors work?
act by preventing the conversion of angiotensin I to angiotensin II. angiotensin II is a potent vasoconstrictor and also contributes to aldosterone secretion
- ace inhibitors decrease BP through systemic vasodilation
- inhibits the aldosterone exception by enhancing excretion of sodium and water and decrease blood volume
- reduces preload, after load, and blood volume= decrease workload of the heart
- also dilates the veins
common side effect of an ACE?
dry productive cough and orthostatic orthostatic hypotension (teach pt to get up slowly)
- is reversed when pt is off med
- switch to an ARB
what should be viewed prior to administration of an ACE inhibitor (Captopril)
the BUN and creatinine should be viewed bc renal insufficiency is another potential side effect of an ACE
-hyperkalemia!!
what is the first line of drug for HF?
ACE/ARBS bc they reduce peripheral edema and increase cardiac output
(replaced digoxin as the drug of choice)
what is the first line of drug for HF?
ACE/ARBS bc they reduce peripheral edema and increase cardiac output
(replaced digoxin as the drug of choice)