Unit 4 Case 2 Flashcards
What is Unit 4 Case 2 about?
A 17-year-old student presented in the ED with chest discomfort, shortness of breath and a ‘racing heart’. She had been drinking lots of energy drinks to revise for exams. She is sent for ECG examinations, and it is revealed she has supraventricular tachycardia (SVT). She had an intravenous injection of adenosine to normalise her heart rate and was told to avoid stress caffeine and alcohol
What is the neuroendocrine response to stress?
The stressor activates the release of corticotropin-releasing hormone (CRH) from the hypothalamus. This causes the synthesis and release of adrenocorticotropic hormone (ATCH) from the pituitary gland. This activates the release of cortisol and epinephrine from the adrenal glands
What is the effect of cortisol on the cardiovascular system?
Cortisol causes vasoconstriction and arteries to narrow which increases blood pressure
How does a lack of sleep affect the cardiovascular system?
A lack of sleep or insomnia increases blood pressure. As when you sleep blood pressure drops, so a lack of sleep keeps blood pressure higher for longer
What is an ECG?
An electrocardiogram is a test to check the heart’s rhythm and its electrical activity.
What are the 3 main components of an ECG?
P wave-atrial depolarisation
QRS complex- ventricular depolarisation
T wave- repolarization of the ventricles
What is the QRS complex?
A combination of 3 different electrical activities that accumulate to be the ventricular depolarisation
What is the QRS wave made up of?
The Q wave which represents the depolarization of the interventricular septum
The R wave represents the electrical stimulus as it passes through the main portion of the ventricular walls
The S wave represents depolarization of the Purkinje fibres
What is a 12 lead ECG and what is the benefit of it?
An ECG involving 12 leads, which are generated from 10 electrodes being placed on the body
Provides spatial information about the heart’s electrical activity
How many chest electrodes are there in a 12 lead ECG?
6
Where are the chest electrodes placed for a 12 lead ECG?
V1- 4th intercostal space at the right sternal edge
V2- 4th intercostal space at the left sternal edge
V3- between V2 and V4
V4-5th intercostal space at the midclavicular line
V5- left anterior axillary line at V4 horizontal level
V6- left mid-axillary line at V4 and V5 horizontal level
What 2 categories are the 10 electrodes on a 12 lead ECG split into?
Chest electrodes
Limb electrodes
How many limb electrodes are there on a 12 lead ECG?
4
Where are the limb electrodes placed in a 12 lead ECG?
Right arm- anywhere from right shoulder to elbow
Left arm-anywhere from left shoulder to elbow
Right leg- anywhere from right torso to ankle
Left leg- anywhere from left torso to ankle
(but must be in the same place on both arms and both legs)
What is meant by sinus bradycardia?
Slow heart rate