Cardiac pathophysiology Flashcards
What are the 5 areas of cardiac conduction in the heart?
Sinoatrial node < internodal / interatrial bundles < Atrioventricular node < Left and Right bundle branches (Bundle of His) < Purkinje fibres.
What are the rates of the following areas?
SA node, AV node, Ventricles.
SA node rate - 60-100
AV node rate - 40-60
Ventricular rates - 20-40
What are the 3 layers of the heart wall called?
Outer - Epicardium
Middle - Myocardium
Inner - Endocardium
How do you calculate cardiac output?
What is stroke volume?
CO = stroke volume x heart rate.
Stroke volume is 70ml in average adults and is the amount of blood pumped from the ventricle with every heart beat.
What does the Left Ventricle do?
The left ventricle pumps oxygenated blood around the body via the systemic circulation. It flows out of the aorta outwards to the body with a force about 5x more than that of the right ventricle.
What does the Right Ventricle do?
The right ventricle pumps deoxygenated blood to the lungs via the pulmonary valve and the pulmonary arteries.
What does the Right Atrium do?
The right atrium receives blood from the superior and inferior vena cava and pushes its volume through the tricuspid valve.
What does the Left Atrium do?
The Left Atrium receives blood from the pulmonary veins and contracts its volume through the mitral valve.
What is the difference between diastole and systole?
Diastole is the relaxed phase of the heart beat, when the ventricles fill passively.
Systole is the contraction phase of the heart beat when the ventricles eject their blood.
What is one small square representing on an ECG strip?
0.04 seconds is one small square.
What is the difference between veins and arteries?
Veins collect deoxygenated blood from tissues and organs and transfer it back to the heart. Arteries take oxygenated blood to tissues and organs. The only exception in arterial oxygenation is in the pulmonary and umbilical arteries.
A caution for GTN is Right ventricular STEMI. How do you tell if it is effecting the right ventricle?
There may be elevation in inferior leads - 2, 3 and aVF.
What are the 4 contraindications for the Valsalva manoeuvre?
The contraindications for the Valsalva manoeuvre are ; unable to obey commands, severe compromise, the Valsalva manoeuvre has been completed twice already, or the dysrhythmia is not the primary clinical problem.
How do you preform a Valsalva manoeuvre?
Explain and gain consent.
Assign one officer to monitor the rhythm.
Sit the pt upright.
Blow forcefully into a 20ml syringe for >15seconds
When they stop blowing, lay the pt flat, and raise their legs.
What are the 7 steps for verification of death?
No signs of breathing for 1 minute.
No palpable central pulse in over 1yo pts.
No palpable brachial pulse in infants.
No audiable heart sounds in the mid clavicular, 4th intercoastal space.
No reacting or undilated pulips.
Wait 10 minutes and repeat.
Print 3 Lead showing Asystole.
