Cardio 3 Flashcards
What are the 6 phases of the cardiac cycle?
- Atrial systole (D)
- Isovolumic contraction (S)
- Ventricular ejection (S)
- Isovolumic relaxation (D)
- Rapid influx (D)
- Diastasis (D)
Pressures in the heart. (Picture)
Vena cava: 5 mmHg
*high pressure = open valves
*low pressure = close valves
*blood goes to high to low pressure flow
Describe ECG’s.
-record of electric potentials generated by heart muscle during each cardiac cycle
-potentials detected on surface of body using electrodes attached to limbs & chest
-potentials amplified by ECG (in voltage & time)
-useful for:
>arrythmias (abnormal HR of sinus node)
>conduction disturbances
Describe the waves in ECGs.
- P wave:
-atrial depol - QRS complex:
-ventricular depol - T wave:
-ventricular repol
Describe the wiggers diagram.
-phases of cardiac cycle with pressure, volume, ECG, heart sounds
-left side of heart only
Describe atrial systole.
diastole
-atria starts contraction after atrial depol
-middle of P wave = causes +20% filling of ventricles
-a wave = caused by atrial contraction
>LA pressure increase to 7-8mmHg
>ventricular pressure curve increase
Describe isovolumic contraction.
-after atrial contraction, ventricles will start to contract
-middle of QRS complex (ventricular depol)
-1st phase of isovolumic contraction
>LV pressure increase
>closure of AV valve
>no volume change
Describe the atrial c wave.
-occurs when ventricles begin to contract
-results in backflow of blood into atria due to ventricular contraction but mainly by closing of AV valves bc of an increase in ventricular pressure
Describe the ejection phase.
-when pressure is high enough to overcome the pressure inside the aorta (80mmHg)
=aortic valve opens & blood is pumped out of LV
-2nd phase = ejection phase
>ventricular volume curve decreases
>aortic pressure curve increases to about 120mmHg (systolic pressure)
Describe the atrial V wave.
-occurs in end of ventricular contraction
-results from slow flow of blood into atria from veins while AV valves are closed
-after ventricular relaxation, AV valves open & atrial blood flows into ventricles & V wave disappears
Describe what happens are the end of the T wave.
-ventricle start to relax = diastole begins
-end of T wave = ventricular repol
-ventricular pressure decrease = aortic valve closes
What is an incisura?
-when aortic valves close
-short period of backflow
-aortic pressure decreases throughout diastole
-before ventricle contract again, aortic pressure = 80 mmHg (diastolic pressure)
Describe isovolumic relaxation.
-when AV & SL valves are closed = no change in ventricular volume
-1st phase of ventricular diastole
Describe rapid inflow.
-when pressure decreases in ventricle = AV valve opens
-blood flows from atria to ventricle = ventricular volume increases
-2nd phase = rapid inflow
>lasts 1/3 of diastole
Describe diastasis.
-middle third of diastole only small amounts of blood flow into ventricles (volume increases)
-3rd phase = diastasis
>persist until SA node initiate an AP leading to atrial contraction
Describe systolic murmurs.
occurs during ventricular systole more common
1. Mitral/tricuspid incompetence
-regurgitation
2. Aortic/pulmonic stenosis
-sistolic turbulence bc valve doesn’t open enough
3. Ventricular septal defect
-hole/cleft in interventricular septum
4. Patent ductus arteriosus
-birth of opening between aorta & pulmonary artery
-continuous murmur = aortic pressure is higher than pulmonary artery during all cardiac cycle
Describe the volume pressure diagram of the cardiac cycle. (A-B: period of filling)
-mitral valve opens due to decrease in ventricular pressure at the end of systole
-left ventricular volume increases due to flow of blood from LA to LV
>atria contract in end increasing volume 120mL & pressure to 5-7mmHg
-end of the diastole & LV contract & mitral valve closes
Describe the volume pressure diagram of the cardiac cycle. (B-C: isovolumic contraction)
-LV pressure rises without volume changes until opening of aortic valve
-pressure inside ventricle increases to equal pressure in aorta (80mmHg)
Describe the volume pressure diagram of the cardiac cycle. (C-D: period of ejection)
-after opening of aortic valve, blood flow into aorta
-ventricular contraction increases during ejection
-volume of LV decreases
Describe the volume pressure diagram of the cardiac cycle. (D-A: isovolumic relaxation)
-end of ejection of aortic valve closes
-LV pressure falls back to diastolic pressure
-no change in volume until mitral valve opens
-new cycle beings
=fills ventricles
