Week 1 Flashcards
Ch. 22: Atrial Fibrillation
A common cardiac dysrhythmia involving atrial contractions that are so rapid that they prevent full depolarization of myocardial fibres between heart beats
Ch. 22: Automaticity
A property of specialized excitable tissue that allows self-activation through the spontaneous development of an action potential, as in the pacemaker cells of the heart
Ch. 22: Cardiac Glycosides
Glycosides (carbohydrates that yield a sugar and a non sugar upon hydrolysis) that are derived from the plant species Digitalis Purpurea and are used in the treatment of heart disease
Ch. 22: Chronotropic Drugs
Drugs that influence the rate of the heartbeat
Ch. 22: Dromotropic Drugs
Drugs that influence the conduction of electrical impulses
Ch. 22: Ejection Fraction
The proportion of blood that is ejected during each ventricular contraction compared with the total ventricular filling volume
Ch. 22: Heart Failure
An abnormal condition in which cardiac pumping is impaired as the result of myocardial infarction, ischemic heart disease, or cardiomyopathy
Ch. 22: Inotropic Drugs
Drugs that affect the force or energy of muscular contractions, particularly contraction of the heart muscle
Ch. 22: Left Ventricular End-Distolic Volume (LVEDV)
The total amount of blood in the ventricle before it contracts, or the preload
Ch. 22: Phosphodiesterase Inhibitors
A group of inotropic drugs that work by inhibiting the enzyme phosphodiesterase
Ch. 22: Refractory Period
The period during which a pulse generator (e.g., the sinoatrial node of the heart) is unresponsive to an input signal of specified amplitude and it is impossible for the myocardium to respond
Ch. 22: Therapeutic Window
The range of drug levels in the blood that is considered beneficial as opposed to toxic or ineffective
Ch. 22: What percentage of the general population does heart failure affect?
Heart failure affects 1% to 2% of the general population, or approximately 450,000 Canadians
Ch. 22: Signs and Symptoms of Left Ventricle Heart Failure
Producing pulmonary edema and symptoms of dyspnea or cough
Ch. 22: Signs and Symptoms of Right Ventricle Heart Failure
Producing symptoms such as pedal edema, jugular venous distention, ascites, and liver congestion
Ch. 22: What is the normal ejection fraction?
Approximately 65% (0.65) of the total volume in the ventricle
Ch. 22: What does increased hydrostatic pressure from the left ventricle lead to?
Pulmonary congestion
Ch. 22: What does increased hydrostatic pressure from the right ventricle lead to?
Systemic venous congestion and peripheral edema
Ch. 22: What are the two types of physical defects producing heart failure?
- A heart defect (myocardial deficiency such as myocardial infarction or valve insufficiency), which leads to inadequate cardiac contractility and ventricular filling
- A defect outside the heart (e.g., systemic defects such as coronary artery disease, pulmonary hypertension, or diabetes), which results in an overload on an otherwise normal heart
Ch. 22: What are the common causes of Inadequate Contractility?
Cardiomyopathy
Coronary artery disease
Infection
Myocardial infarction
Ch. 22: What are the common causes of Inadequate Filling?
Atrial fibrillation
Infection
Ischemia
Tamponade
Ch. 22: What are the common causes of Pressure Overload?
Hypertension
Outflow Obstruction
Ch. 22: What are the common causes of Volume Overload?
Anemia
Congenital abnormalities
Hypervolemia
Thyroid disease
Ch. 22: What is the most frequently prescribed cardiac glycoside?
Digoxin is the most fequenly prescribed cardiac glycoside and the only one currently available in Canada