Heart Failure Drugs Flashcards
(42 cards)
Heart Failure Defined and symptoms
HF:
- when CO is inadequate to provide O2 needed by the body
Symptoms:
- Tachycardia, decreased exercise tolerance, peripheral/pulmonary edema, cardiomegaly
Risk factors for HF
Hypertension CAD MI Diabetes Family History Use of Cardiotoxins Obesity
HFrEF vs HFpEF
Systolic HF (contraction problem)
Diastolic HF (filling problem) - more difficult to treat
Pathophysiology of HF
CHF:
abnormal increases in blood volume and interstitial fluid.
- LHF = dyspnea from pulmonary congestion
- RHF = peripheral edema
Role of Physiological Compensation in HF
The decrease in CO causes the SNS and RAAS to activate which increases all factors that will exacerbate heart failure
- by increasing force, preload, after load, and remodeling
Preload
force of contraction depends on how far the myocardial cells are stretched. (increasing preload will increase contractility)
** this has a limit
HF- preload is beyond stretching limits and thus increase in preload causes a decrease in contractility
Afterload
Force against which ventricles must act
- based on vascular resistance
Contractility
Force of cardiac muscle contraction is directly related to calcium levels
Sources: Voltage sensitive calcium channels, Na+/Ca2+ exchanger, and SR
Removal: Na+/Ca2+ exchanger, Reuptake into the SR
Therapeutic Strategies for HF
HF is a progressive disease - only cure is transplant
- treatment is directed towards:
1) reducing symptoms and slowing progression
2) managing acute episodes
Chronic HF therapeutic Strategies
Light aerobic exercise Low dietary sodium Smoking cessation Decreasing weight Fluid restriction Treat comorbid conditions Use: ACEI, diuretics, beta blockers, and Inotropic agents ** DO NOT USE: NSAIDS, Ca2+ channel blockers, and alcohol
Drugs to Treat HFrEF (systolic)
Diuretics Spironolactone (K-sparring: aldosterone antagonist) ACEI/ARBs Direct vasodilators Beta blockers Inotropic agents
Drugs to Treat HFpEF (diastolic)
Diuretics (be careful with reducing SV to much)
ACEI/ARBs
beta-blockers
Calcium channel Antagonist
AHA classification of HF
Stage 1: high risk for developing HF
- HTN, DM, CAD, Family history
Stage 2: Asymptomatic HF
- previous MI, LV dysfunction, Valvular heart disease
Stage 3: Symptomatic HF
- Structural heart disease. dyspnea and fatigue, impaired exercise tolerance
Stage 4: Refractory End Stage HF
- Marked symptoms at rest despite maximal medical therapy
NYHA classification of HF
Class I: No symptoms with ordinary physical activity
Class II: Ordinary physical activity somewhat limited by dyspnea (e.g climbing 2 flights of stairs)
Class III: Exercise is limited by dyspnea with moderate workload (e.g climbing 1 flight of stairs)
Class IV: Dyspnea at rest with little exertion
Recommended therapy for CHF
Diuretics. beta blocker, ACEI
Diuretics
Relieve pulmonary congestion and peripheral edema
reduces symptoms of volume overload
decrease plasma volume –> decreases VR –> decreases cardiac workload and O2 demand
Also decreases after load (reducing plasma volume and decreasing BP)
Clinical App. Diuretics
No evidence of mortality benefit alone
Thiazide infective with congestive symptoms
Loop: more effective (if edema is present)
ACEI
Agents of choice for HF
- Decrease vascular resistance and BP –> Increase CO by decreasing afterload
- decrease in Na+ and H2O retention (dec. preload)
- decrease in long term remodeling of the heart
Clinical App. ACEI
Recommended:
- Symptomatic HF
- Asymptomatic patients with Decrease LFEF or history of MI
Suggested:
- patients at high risk of HF
AE of ACEI
Hypotension Dry cough hyperkalemia angioedema acute renal failure (bilateral renal artery stenosis) Teratpgenic
ARBS
Potent competitive antagonist of angiotensin II type I receptor (AT1 receptor)
do not produce dry cough
substitute for patients that can not take ACEI
AE: similar to ACEI and also teratogenic
Direct Vasodilators
Hydralazine + Isosrbide dinitrate
- vasodilation –> decrease preload
- arterial dilation –> decreases PVR and afterload
(hydralazine - arterioles and nitrates- venules)
Clinical app. Direct Vasoldilators
Patients who can not take ACEI or ARB
or
In African Americans with advanced stage HF (as adjunct)
Direct vasodilators AE
Headache, dizziness. tachycardia. peripheral neuritis, and lupus like syndrome
Contraindicated: Sildenafil (severe hypotension)
