Embed Size (px)
Citation preview
Chapter 17
Cardiac Stimulants and Depressants
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 2
The Heart
The heart is a four-chamber organ located in the upper left thoracic cavity.
Purpose Pumps the blood around the body so that
oxygen and nutrients can be distributed to all areas of the body
Maintains the blood pressure at an acceptable level
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 3
Antiarrhythmics and Antianginals
Cardiac illnesses Cardiac stimulants Cardiac depressants
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 4
Treatment of Heart Failure
Cardiac glycosides Digoxin Treat arrhythmias
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 5
Digoxin
Decreases electrical conduction Prolongs refractory period Increases the force of the myocardial
contraction Positive inotropic action
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 6
Digoxin: Dose Considerations
Duration of action Method of administration Other
Physical size of the client Other medications Renal or hepatic function Advanced age Presence of other illnesses
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 7
Antiarrhythmics and Antianginals
Require a digitalizing dose To bring serum levels to a therapeutic level All glycosides have a low therapeutic level
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 8
Gastrointestinal effects Nausea and vomiting Anorexia Diarrhea
Cardiac effects Cardiac arrhythmias
(continues)
Antiarrhythmics and Antianginals: Side Effects
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 9
Antiarrhythmics and Antianginals: Side Effects
Neurological effects Restlessness Irritability Drowsiness Vision changes Headache
(continued)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 10
Cardiac Glycoside Toxicity
Predispose to cardiac glycoside toxicity Hypokalemia Renal impairment Rapid IV administration
(continues)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 11
Cardiac Glycoside Toxicity
Treatment Stop the drug Physical assessment Check potassium level
Administer if needed Monitor heart rate
Administer antiarrhythmics
(continued)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 12
Antiarrhythmic and Antidysrhythmic Drugs
Grouped together according to their similar actions
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 13
Antiarrhythmics and Antianginals: Drug Action
Work three ways: Decrease the automaticity of cardiac
tissues in the ectopic sites Alter the rate of conduction of electrical
impulses through the heart. Alter the refractory period of cardiac
muscle between consecutive contractions
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 14
Antidysrhythmic Agents
Group 1, 1A, 1B, 1C: decrease the influx of sodium ions, stabilizing membranes
Group 2: depress phase 4 in depolarization
Group 3: prolong repolarization in phase 3 Group 4: depress phase 4 depolarization
and prolong repolarization of phases 1 and 2
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 15
Beta-adrenergic Blocking Agents
Inhibit beta1 and beta2 sympathetic receptors
Reduce heart rate Reduce contractility Decrease supraventricular and
ventricular rhythms Decrease blood pressure
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 16
Antidysrhythmic Agents
Adverse effects Cause bronchoconstriction Cause heart failure
Examples: propanolol (Inderal), esmolol, bretylium tosylate (Bretylol)
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 17
Calcium Channel Antagonists
Reduce the influx of calcium into the cell:
Prevention or reversal of spasms of the coronary blood vessels
Coronary artery dilation Reduction of myocardial oxygen consumption
Example: verapamil
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 18
Adenosine
Slow conduction through the AV node Cardioverts paroxysmal
supraventricular tachycardia (PSVT) Side effects
Facial flushing Shortness of breath Headache Nausea and vomiting
Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved.
17 - 19
Adrenergic or Sympathomimetic
Drugs Affect alpha- or beta-adrenergic
receptors Treat shock
Mimic epinephrine and/or norepinephrine Cause increase in heart rate Cause vasoconstriction Reverse hypotension from shock
Cardiac or trauma
