Vagal Maneuvers Flashcards
What are 2 types of atrial tachycardia?
- Atrial flutter
2. Atrial fibrillation
What is a result of atrial tachycardia, such as an atrial flutter or atrial fibrillation?
The AV node sends electrical impulses at a very high rate driving ventricular contraction at a higher rate to the point that their effectiveness is impaired.
What can slow down the increased rate caused by atrial tachycardia?
Acetylcholine
How does acetylcholine reduce the increased rate of atrial tachycardia?
By slowing impulse conduction at the AV node.
What is a vagal maneuver on the heart?
Application of acetylcholine, which increases parasympathetic activity through the decreasing of ventricular contraction rate.
Explain what a Valsalva maneuver is.
When one makes a forced expiratory effort against a closed airway (ex. grunting). This raises intrathoracic pressure. When you open the closed airway, intrathoracic pressure drops, which causes the transmural pressure to increase and stretch against the walls of the aorta. This causes a decrease in preload, which the baroreceptors then detect.
What happens when the aortic baroreceptors are stimulated by stretching?
A reflex stimulus activates the vagus nerve for a response.
What is an external way you can stimulate the baroreceptors?
Massaging the carotid sinus artery.
What happens when you stimulate the vagus nerve through the baroreceptors?
The nerve sends a signal to slow the heart.
What sort of compounds can help treat supraventricular tachycardias?
Digitalis compounds
What do digitalis compounds do?
Increase vagal nerve innervation and decrease sympathetic innervation of the AV node of the heart.
High sympathetic tone is synonymous with?
High sympathetic innervation
Patients with a congestive heart failure have a ___ baseline vagal tone and a ___ baseline sympathetic tone.
low vagal tone ; high sympathetic tone
To be conceptually thorough, digitalis compounds in a patient with congestive heart failure would do what?
Increase cardiomyocyte contractility and increase cardiac output (due to blocking of premature contractions). This also causes a reflex stimulation of the vagus nerve.
