3 Flashcards
What makes up the right border of the heart?
(SVC) and right atrium
What makes up the inferior border of the heart?
The right and left ventricle
What makes up the left border of the heart?
Left ventricle and some of the left atrium (the left auricular appendage)
What makes up the superior border of the heart?
The right and left atrium and the great vessels
The anterior mediastinum is the part closest to the …………..
sternum
The posterior mediastinum is the part closest to the ……….
spine
What is the coronary sulcus/atrioventricular groove?
It is a groove that runs transversely around the heart. It represents the wall dividing the atria from the ventricles.
What is the oblique pericardial sinus?
A blind ending passageway located on the posterior surface of the heart.
What is the transverse pericardial sinus?
A passageway found superiorly on the heart. It separates the arterial vessels and the venous vessels of the heart.
What is pericardial effusion?
An accumulation of fluid in the pericardium.
What does pericardial effusion cause?
It puts pressure on the heart, affecting diastole- the heart cannot fill properly. This is called cardiac tamponade.
Explain diastole and systole.
Systole occurs when the heart contracts to pump blood and diastole occur when the heart relaxes and fills with blood after contraction.
Define cardiac tamponade.
Compression of the heart due to fluid build up in the sac surrounding the heart.
An ECG is a ………../…………. graph.
voltage/time
A standard ECG trace is how many cm and seconds long?
25cm, 10 seconds.
What does the P wave and the flat line after represent?
Atrial depolarisation.
Transmission through the AVN.
Why is the P wave a small wave?
There is less electrical tissue than in the ventricles.
Transmission through the AVN is …….. to allow ventricles to fill.
slow
Transmission through the AVN is …….. to allow ventricles to fill.
slow
What does the QRS complex represent?
Ventricular depolarisation.
Atrial repolarisation occurs but isn’t seen on the ECG
What does the T wave represent?
Ventricular repolarisation
What is the QT interval?
What are the normal values?
A measure of the time to ventricular repolarisation.
Men: 350-440 ms
Women: 350-460 ms
How long does the interval between the P wave and QRS complex last?
120-200 ms
How long does QRS complex last?
<120 ms
What is the difference between electrodes and leads?
An electrode is a physical connection to the patient which measures a potential at that point and a lead is the graphical representation of the electrical activity.
How many electrodes record 12 lead ECG?
10 electrodes.
How many leads on a 12 lead ECG?
12
What are the 4 limb electrodes and their colours?
RA - Red
LA - Yellow
RL - Black
LL - Green
Which of the limb electrodes is neutral and used to reduce artefacts?
RL Black
Explain what is meant by bipolar when referencing limb electrodes:
Single positive and a single negative electrode between which electrical potentials are measured.
Explain what is meant by unipolar when referencing limb electrodes:
Single positive recording electrode and utilize a combination of the other electrodes to serve as a composite negative electrode.
Name the 12 leads.
Lead I Lead II Lead III aVR aVL aVF V1 V2 V3 V4 V5 V6
Which part of the hearts circulation do the lateral leads correspond to?
Circumflex artery.
Which leads are lateral?
aVL, Lead I, V5 and V6.
Which part of the hearts circulation do the anterior leads correspond to?
Left anterior descending artery.
Which leads are anterior?
V2, V3 and V4.
Which part of the hearts circulation do the inferior leads correspond to?
Right Coronary artery.
Which leads are inferior?
Lead II, Lead III and aVF.
Which lead is septal?
V1
Which leads are the chest leads?
V1-V6.
Which leads are bipolar?
Limb leads- Lead I-III
Which leads are unipolar?
Limb leads- aVR, aVL and aVF
Chest leads- V1-6
