failure of heart as a pump.

·        Ventricular dysfunction

·        Reduced cardiac output

·        Inadequate tissue perfusion

·        Flud overload

Causes

Congestive heart failer CHF

• Shortness of breath
• Swelling of feet and ankles
• Urinating more frequently at night
• Pronounced neck veins
• Palpitations (sensation of feeling the heart beat)
• Irregular fast heartbeat
• Fatigue
• Weakness
• Fainting

• Shortness of breath
• Difficulty lying down; need to sleep with the head elevated to avoid shortness of breath
• Sensation of feeling the heartbeat (palpitations)
• Irregular or rapid pulse
• Cough (produces frothy or blood-tinged mucus)
• Fatigue, weakness, faintness
• Weight gain from fluid retention
• Decreased urine production (oliguria)

Body responds to general threat of inadequate oxygen supply

·        Cardiac stimulation

·        Kidneys retain fluid

1. an agent that improves the pumping action of the heart

1. Therapeutic goals

1.  
   1. Improved cardiac output (amount of blood pumped by the ventricle in 1 minute)
   2. Normal sinus rhythm (normal electrical conduction

1.  
   1. increases force of myocardial contraction

1.  
   1. decreased heart rate

1.  
   1. decreased rate of impulse conduction through the heart

1.  
   1. decreased heart rate, increased strength of contraction

Positive inotropic effect

Negative chronotropic effect

Negative dromotropic effect

Net effects

Uses-

• Heart failure (CHF or HF)
• Treatment of some dysrhythmias (dysrhythmia, an abnormal cardiac rate or rhythm)

1. Common adverse effects

1.  
   1. Cardiac-b r a d y c a r d ia, other dys rhy th mia s
   2. GI- Anorexia, nausea, vomiting
   3. CNS-confusion, visual disturbances

Classification of drugs used to treat heart failure

• Cardiac glycosides
• Phosphodiesterase inhibitors
• Ace inhibitors
• Human natriuretic peptide b-type
• Endothenlin receptor antagonists

CLASS

Digitalis (cardiac glycoside)

PROTOTYPE

digoxin (lanoxin)

given PO or IV

MECHANISM

Increases influx of Ca++ into myocardial cells which increases activation of actin and myosin, thereby increasing myocardial contractility.

Increases myocardial contractility, slows SA firing and AV conduction  

UNIQUE FEATURES 

Hypokalemia increases risk of digitalis toxicity.

Digitalizing and maintenance doses.

CLASS

Phosphodiesterase inhibitors  

PROTOTYPE 

amrinone (Inocor)  

MECHANISM

Increases myocardial contractility by increasing cAMP in myocardial cells.

a Peripheral vasodilation.

UNIQUE FEATURES 

Used for short-term tx of acute, severe CHF that does not respond to digitalis, diuretics, and vasodilators.  

CLASS

ACE Inhibitors  

  PROTOTYPE

captopril (Capoten)  

MECHANISM

Inhibits renin-(enzye) produced in kidneys in response to impaired blood flow and tissue perfusion

Angiotension 1 to angiotension 2- 1(vasoconstricts, 2

Stimulates aldosterone system (Na and water retention, K excretion) resulting in peripheral vasodilation.

Decreases preload and afterload

Decreases cardiac workload

Improves perfusion  

UNIQUE FEATURES 

First line tx along with diuretics for chronic heart failure.

Monitor serum potassium and creatinine.

Can cause chronic cough

 CLASS

Human natriuretic peptide B-type  

PROTOTYPE

Nesiritide (Natrecor)

MECHANISMS

Diuresis; suppresses renin-angiotensin-aldosterone system; (neurohormon that is vasoconstrictor)

 decreases norepinephrine and endothelin  

UNIQUE FEATURES

Incompatible with most other drugs in IV infusion.

Can cause hypotension, v.tach, bradycardia, nausea, vomiting, anxiety

 CLASS

Endothelin receptor antagonist  

PROTOTYPE

Bosentan (Tracleer)  

MECHANISMS

Relaxes blood vessels to decrease cardiac workload

UNIQUE FEATURES

FDA approved only for pulmonary hypertension 

1. Nursing Interventions

·        Apical heart rate

·        Peripheral edema

·        Activity tolerance

·        Respiratory status

·        Serum potassium

·        Fluid intake and output

·        weight