Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

INT 208: Pharmacology > Reduced ejection Fraction HF 2: Digitalis > Flashcards

Reduced ejection Fraction HF 2: Digitalis Flashcards

1
Q

General action of Digitalis on Heart

A
  • Positive Inotropic
  • Negative Chronotropic
  • Negative dromotropic
  • Ventricular arrhythmia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mechanism of Action of digitalis

A
  • Inhibits SAN
  • Inhibits AVN
  • Stimulates Atrial Contractility
  • +ve inotropic (direct action)
  • Toxic dose –> increase automaticity of Purkinje fibres —> Arrhythmia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mechanism of Action of positive inotropic effect of Digitalis

A

Increases intracardiac calcium by inhibitin Na+k+ ATPase:
1. Inhibit Na+k+ ATPase
2. 2 K+ decrease intracellular , 3Na+ increase intracellular
3. blockage of Na+ Ca2+ exchanger –> retention of Ca2+
4. increased calcium induced Calcium induced calcium release —> Calcium secretion from sarcoplasmic reticulum
5. Increase contractility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mechanism of Action of Negative Chronotropic/Bradycardia effect of Digitalis

A

both vagal stimulation & direct:
* Small dose: vagal tone only
* Large dose: vagal tone + direct inhibition of SAN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

true or false, Atropine can antagonise high dose Digoxin bradycardia effect

A

false, at high dose, it works both Vagal & directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

effect of digoxin on excitability & Automaticity of the heart

A
  • Increased excitability
  • Increased Automaticity =especially in purkinje fibers due to -ve dromotropy (less conncection with SAN)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Effect of Digitalis on ECG

A
  • Long P-R interval
  • Depressed S-T segment
  • Inverted T wave
  • pulsus bigeminus & Trigeminus (arrhythmia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

effect of Digitalis on Cardiac Output

A

Increased, due to increased filling/ Stroke volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

effect of digitalis on BP

A

normalisation of increased systolic & decreased diastolic (reduce pulse pressure from both aspects)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

effect of digitalis on kideny

A
  • Increase GFR
  • Decrease renin, Angiotensin, Aldosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

effect of Digitalis on GIT

A
  • Vomiting
  • Affects CTZ center
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

effect of digitalis on CNS

A
  • stimulates VMC
  • Stimulates CTZ center
  • toxic doses especially in elderly –> confusion & hallucinations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

effect of digitalis on Endocrine

A

may cause Gynecomastia in males

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Theraputic uses of Digitalis

A
  • HF after other treatments & still symptomatic
  • Atrial fibrillation
  • Atrial flutter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Explain why digitalis is used in atrial fibrillation & Atrial flutter despite worsening Atrium (increase atrial conductivity)

A

to protect the ventricle, by delaying the Atrio-ventricular conduction, so ventricle will be:
* Slower
* More regular
* more efficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Contraindications of digitalis

A
  • Ventricular arrhythmia (worsens)
  • Partial or complete heart block
  • Cardiac ischemia (angina, infarction)
  • Sick sinus syndrome/ impaired SAN
17
Q

Drug interactions of digitalis

A

Decreasing activity of digitalis:
* Decreasing absorption: anti-acids (Mg & Al)
* Increasing K+: potassium sparring diuretics (spironolactone)

Increasing activity of digitalis:
* Hypokalemia: thiazide & Loop diuretics
* Hypercalemia: thiazide diuretics
* Beta blockers –> heart block

18
Q

Manifestations of Digitalis toxicity

A

GIT:
* Nausea
* Vomiting
* Anorexia
* Diarrhea
* cramps

CVS:
* Bradycardia (less than 60bpm)
* Heart block
* atrial & ventricular Arrhythmia
* flutter & fibrillation (cause of death)
* pulsus bigeminus & trigeminus

CNS:
* Hallucination
* Delusion
* Confusion
* Convulsions
* Excitation
* Headache
* Coloured vision (chromatopsia)–> yellow & green vision

19
Q

Factors that increase Digoxin toxicity

A
  • Extermities of age
  • Hypokalemia
  • Drug interactions that increase its activity (thiazides, loop diuretics, beta blockers)
  • Hyperclacemia
  • Hypothyroidism
  • Hypomagnesemia
  • Kideny disease
20
Q

Treatement of Digoxin Toxicity

A
  • Stop digitalis
  • Stop K+ depleting (thiazide & loop) diuretics
  • oral activated charcoal
  • if hypokalemic, give potassium chloride (but not in Heart block & renal impairment)
  • Digoxin Antibody
21
Q

drug of choice in Digoxin induced ventricular arrhythmia with heart block

A

Phenytoin

22
Q

drug of choice in Digoxin induced ventricular arrhythmia without heart block

A

Lidocaine

23
Q

drug of choice in Digoxin induced heart block or sinus bradycardia

A

Atropine

24
Q

drug of choice in Digoxin induced ventricular fibrillation

A

Electro-cardioversion

INT 208: Pharmacology (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions