CV System Flashcards
Function if cv system
Gaseous exchange Nutrition and waste transport Hormones Immune system function Temperature regulation
Artery supping brain
Carotid artery
Artery supplying arms
Subclavian artery
Artery supplying stomach and intestines
Mesenteric artery
Artery supplying liver
Renal artery
Artery supplying lower limbs
Iliac artery
Layers of the heart
Endocardium Myocardium - 75% of heart muscle mass - electrical signals pass through Epicardium Pericardium
Stages of the cardiac cycle
Artrial contraction Isovolumetric contraction Ventricular ejection Isovolumetric relaxation Artrial filling Ventricular filling
Describe the SA node
Located in RA
Pacemaker
Naturally beats at 100 bmp
Altered by sympathetic and parasympathetic
Why does the AV node delay the impulse slightly
Allows time for atria to fully contract and blood to enter the ventricles
Stages of an ecg and what they show
P wave - atrial depolarisation
QRS complex - ventricular depolarisation
T wave - ventricular repolarsation
PR interval - time between atrial and ventricular depolarisation
ST segment - ventricular repolarisation
Describe cardiac cells
Involuntary
Striated
Branched
Intercalated discs
Gap junctions
Desmosomes
Increased mitochondria
3 layers of blood vessels
Tunica externa - fibrous outer layer
Tunica media - muscular layer
Tunica intima - inner layer, secretes key nutrients and signals
Name the left Coronary arteries and where the supply
Left coronary artery - LA and LV
Left anterior descending - LV, septum and bundle of his
Circumflex - posterior or heart
Name the right coronary arteries
Right coronary artery - RA, RV and LV
Posterior descending
Right marginal artery
Stages of atherosclerosis
Damaged endothelium
LDL penetrates into the intima and attracts monocytes
Monocytes attach your LDL to form foam cells and clusters to make fatty plaques
When the foam cells die they release lipid signalling, smooth muscles cells migrate to intima
Cells divide and form protein and collagen matrixes enlarging plaque size
Plaque is prone to rapture and thrombus formation
What is angina
Pain experienced when O2 demand exceeds O2 supply
Ischemia causing pain
Signs and symptoms of angina
Tightness, burning or dull pain in chest pain or heavy feeling in left arm
Pain or discomfort radiating to jaw
Breathlessness on exertion
Role of valves
Prevent backflow
Open and close with pressure changes
Name the 4 main heart valves and their location
Mitral - LA->LV
Aortic valve -LV -> aorta
Tricuspid - RA -> RV
Pulmonary - RV-> pulmonary artery
Arrhythmia
What?
Not a sinus rhythm
Causes of arrhythmia
Heart attack Mi Heart failure Valve disease Cardiomyopathy
Describe atrial fibrillation
Most common
Rapid/irregular impulses in atria
Caused by numerous abnormal foci
Symptoms of atrial fibrillation
Palpitations
Irregular pulse
HTN at high HR
AF care pathway
Diagnose - ecg, 24h ecg, loop recorder Prevent stroke - anti coagulation drugs Rate control - slow HR and protect LV Rhythm control - anti-arrhythmias Interventions - cardioversion, catheter ablation
Describe atrial flutter
Electrical impulse from SA node form an irregular current
Impulse circulates very fast
Ventricles can’t beat that fast
Often progresses to AF
Bradycardia
HR <60bpm
Causes
- normal/fitness
- SA node issue
- heart block
Only a concerned when combined with dizziness
Describe Ventricular tachycardia
Rapid hr in ventricles
Can’t fill and contract efficiently
May be brief and harmless
Long lasting cab become life threatening
Describe Ventricular fibrillation
Radio chaotic electrical impulse causes ventricles to quiver ineffectively
May occur after a Mi
Can escalate to cardiac arrest and be fatal
Ectopic beat
Early or extra heart beat originating somewhere other than the SA node
Common and usually harmless
Can develop into life threatening arrhythmia
Method to diagnose arrhythmias
Alivecore
Loop recorders
Ecg
Arrhythmia interventions
Cardioversion
- shock heart back into normal rhythm
- treats symptoms not cause
Cardio ablation
- uses guide catheter
- stimulate heart to have an arrhythmia to see where it originates
- burn it freeze cels causing it
Describe pacemakers
Artificially replace the hearts intrinsic pacing
Can be single, dual or biventricular
Describe what the 4 numbers on a pacemaker stand for
I - which chamber being paced - A,V or D
II - sensing for hearts intrinsic signals - if it sensed a natural signal, it will not stimulate - 0 A, V or D
III - the response to II - inhibited, triggered or Dual
IV - rate responsiveness, special sensor detects movement and helps HR adjust to meet demand
What do ICDs do
Send inplules to regulate abnormal and dangerous rhythms
what is stenosis
when a valve doesnt open properly
reduces blood flow
what is a regergitant valve
a valve that doesnt close properly
blood back flows
effect of atrial stenosis
increased LV workload
LV hypertrophy - not functional, reduced LV size
effect of atrial regergitation
increased LV workload, LV dilation
what is mitral stenosis and effect
fulid on the lungs
what is the effect of mitral regergiataion
LA dilation
LV failure
causes of a murmur
Rheunmatic fever - not common in UK
calcifiation - atherscolersis, progressive
bicuspid - 2 leaflets rather than three
symptoms of a heart murmur
dysponea
syncope
angina
fatigue
diagnosis of a murmur
echocardiogram
medications
Reduce HTN
anti coagulatants
interventions of a heart murmuer
valve replacement
TAVI
pros and cons of a mechanical valve
last indefinetly
require anti coagulant medication
open heart surgery
what is hypertrophic cardiomyopathy
LV becomes thickened and stiff reducing ability to contract and relax
weaker contractions
what is dialted cardiomyopthay
LV becomes weak and enlarged which reduces it abilty to pump
what is arrhythmogenic cardiomyopthy
fat and scar tissue infiltrates heart muscle effecting electrical pathways
causes of cardiomyopthay
genetic
lifestyle
pregency/virus
symptoms of cardiomyopathy
teird dizzy SOB chest pain swelling in stomach and ankles
how is left ventricle dysfunction measured
using ejection fraction
50-70% is normal
what is heart failuer
inability of heart to meet oxygen demands of the tisues
classes of heart failure
I - no symptoms
II - mild symptons, occasional swelling, activites somehwat limited
III - noticable limitaions, comforatble only at rest
IV- unable to do any form of PA, symptoms at rest
Symptoms of heart failure
fatigue
SOB
Chest pain
swelling in stomach and ankles
diagnosis of heart failure
ECHO - ultrasound of the heart, non invasive, structure and function of heart, allows you to take measurements
Cardiac MRI - non invasive, high res image
causes of myocaridal infarction
reputed plaque and thrombus formation which occludes the lumen
irreversible death of cardiac tissue
presentation of an MI
similar to angina
- intense pain/pressure in the chest
- radiation to throat and arm
- indigestion
- nausea/vomiting
- weakness
- breathlessness
- fear of impending doom
what is a STEMI
st elevated MI
ST elevation on ecg
raised troponin
= full thickness heart damage
whats is a NSTEMI
no st elevation
raised troponin
= partial thickness damage to heart muscle
mycocardial perfusin test
thallium injected into veins
ischemic or necrotic cells will not take up thallium
shows site and size of ischemia
can be done at rest or exercise
angiography
radioplaque dye injected via cathetre into coronary arteres
visible of xray, CT and MRI
local anaesthetic
Measures
- site, number and severity of stenosis
- helps determine best cause of treatment
CT Coronary angiogram
much less invasive
xray blood flow through heart
dye injected into vein in arm
CT fractional flow reserve
new technique
computer based non-invasive CTCA
coronary mapped out
evaluates the haemodynamic relveance of stenosis
- measures flow rate before and after stenosis size change and treatments
