Applied Anatomy Of The Heart Flashcards
Heart innervation
SAN AVN. Bundle of His. Left and right bundle branches. Purkinje fibres
3 components of the cardiac plexus
Vagus nerve
Sympathetic nerves
General visceral afferent nerves
Effect of vagus nerve on firing rate
Decrease
Effect of sympathetic chain ganglia on rate of firing
Increase
Where do heart sympathetic fibres enter the spinal cord
T1 - T5
What causes referred pain
Brain cannot distinguish between visceral and somatic sensation
What vessel usually supplies the SAN and AVN
Right coronary artery
What vessel usually supplies the bundle branches
Interventricular arteries
How do impulses travel through the heart if a bundle branch becomes ischaemic
Through myocytes
How does bundle branch block impact ECG
prolonged QRS
How long does severe ischaemia take to cause ECG changes
Minutes
What is stenosis
Valves don’t open properly
What is regurgitation
Valves don’t close properly
Causes of valvular dysfunction
Aging
Rheumatic fever
Bacterial endocarditis
Are mitral regurgitation and aortic stenosis systolic or diastolic murmurs
Systolic
Are mitral stenosis and aortic regurgitation systolic or diastolic murmurs
Diastolic
What is mitral regurgitation
Blood moves through Mitral valve during systole
Where is the murmur heard in mitral regurgitation
Apex
Pansystolic, louder in late systole
What causes the murmur in aortic stenosis
Turbulence as blood pushed through stenotic aortic valve
Where and when is the murmur heard in aortic stenosis
Systolic - usually mid systolic
Right 2nd intercostal space
Is aortic stenosis more severe when the murmur is heard in early or late systole
Late
What does a mitral stenosis murmur sound like
Soft rumbling
What is cardiac remodelling
Heart muscle changing size based on workload
Pre load
Volume of blood in ventricles at end of diastole
Afterload
Resistance ventricle must overcome to circulate blood
Concentric hypertrophy
Wall thickness increased by new sarcomeres due to increased afterload
How does concentric hypertrophy affect compliance
Decreased
Eccentric hypertrophy
Reduced compliance leads to volume overload, follows on from concentric hypertrophy
What is eccentric hypertrophy
Chamber dilation
How does eccentric hypertrophy effect oxygen demand and mechanical efficiency
Increases oxygen demand
Decreases mechanical efficacy
Atrial remodelling
Any persistent change in atrial structure
Does atrial fibrillation risk increase or decrease with increasing atrial size
Increase
Atrial fibrillation
Ectopic firing and re entry of electrical activity
What is absent in the ECG of a person with atrial fibrillation
P waves
