Cardiology Flashcards
Describe the three shunts of Foetal Circulation. What happens during birth to these shunts
- Ductus Arteriosus (Connects Aorta to Pulmonary Artery, bypassing Pulmonary circulation)
- Ductus Venosus (Connects Umbilical Vein to Inferior Vena Cava, bypassing liver)
- Foramen Ovale (Connecting R and L atria)
During birth, air enters alveoli causing a decrease in pulmonary resistance. Blood takes path of least resistance and now enters pulmonary circulation. Also a drop in prostaglandins cause the foramen ovale to close, becoming fossa ovalis. Ductus arteriosis becomes Ligamentum arteriosus, and Ductus venosus becomes Ligamentum venosus
What is the murmur of Patent Ductus Arteriosis?
Systolic crescendo-decrescendo “machinery” murmur, with ability to hear S1 but not S2. Radiation to back / between scapula. Left subclavicular thill, large bounding and collapsing pulse, with a wide pulse pressure
What are the risk factors of Patent Ductus Arteriosis?
High altitude, prematurity, rubella, hyaline membrane disease
Is Patent Ductus Arteriosis cyanotic or acyanotic?
What is the pathophysiology?
Acyanotic
Blood moves from high to low resistance, this from aorta to Pulmonary artery, causing a L -> R shift, pulmonary HTN and RVH. Deoxygenated blood does not enter systemic circulation, thus patient is acyanotic
What is the murmur of Atrial Septal Defect?
Systolic crescendo-descendo murmur, can hear S1 and there is also fixed S2 splitting. Heard best in upper left sternal border
What are the three types of Atrial Septal Defect? What are they associated with?
- Ostium Secundum (Holt-Oram syndrome)
- Patent Foramen Ovale (Migraine with aura)
- Ostium Primum (Down’s syndrome)
All are also associated with Foetal Alcohol Syndrome
Outline pathophysiology of Atrial Septal Defect. Is it cyanotic or acyanotic?
During development, the Septum primum travels down to the endocardial cushion, producing an Ostium primum as it does so. This however becomes redundant and an Ostium Secondum forms superior to it. A Septum secondum travels down also, forming a Foramen Ovale. This structure behaves as a valve between two atria, until they are ideally closed during birth
If it is not, there is communication still, causing a L -> R shift, pulmonary HTN and RVH. Acyanotic as deoxygenated blood does not enter systemic circulation
What are the ECG findings for an Ostium Secondum / Ostium Primum ASD?
Ostium Secondum - RBBB and RAD
Ostium Primum - RBBB and LAD
How is Patent Ductus Arteriosus treated?
Symptomatic -> Indomethacin (Prostaglandin Inhibitor)
Asymptomatic -> Echo monitoring upto 1 year old, followed by Transcatheter / Surgery to close
How is Atrial Septal Defect treated?
- Anticoagulants (Warfarin, Aspirin, NOACs)
- Transcatheter Surgery
What are the associations with Ventricular Septal Defect?
Down’s syndrome
Edward’s syndrome
Patau syndrome
Turner’s syndrome
Post-myocardial infarction
What is the murmur of Ventricular Septal Defect?
Pansystolic murmur, heard best on the L lower sternal border with radiation to the RHS
Outline pathophysiology of Ventricular Septal Defect. Is it cyanotic or acyanotic?
Communication between R and L ventricle. Blood shifts from L -> R, causing pulmonary hypertension and RVH. Acyanotic because deoxygenated blood does not enter systemic circulation
What are the three causes of Eisenmenger’s Syndrome?
- Patent Ductus Arteriosus
- Atrial Septal Defect
- Ventricular Septal Defect
What is the Pathophysiology of Eisenmenger’s Syndrome?
PDA, ASD and VSD all cause L -> R shunts, leading to Pulmonary HTN and RVH. Over time however, the RVH causes the pulmonary pressures > systemic pressures, leading to a reversal of the L -> R shunt. As a result, deoxygenated blood enters systemic circulation causing cyanosis
Why do patients with Eisenmenger’s have a plethoric complexion?
Cyanosis causes stimulation of bone marrow to respond to hypoxia by releasing more RBCs, leading to polycythaemia, a plethoric complexion and an increased risk of DVT / PEs
What cardiovascular findings are present with Eisenmenger’s?
Loud P2
Right ventricular heave
Raised JVP
Clubbing
What is the non-definitive and definitive management for Eisenmenger’s?
Polycythaemia - Venesection
Pulmonary HTN - Sildenafil
Thrombosis prophylaxis - Anticoagulation
Infective Endocarditis - Prophylactic ABX
Definitive: Heart + Lung Transplant