MD3 Block 1 Cardiovascular System Quiz 1 Flashcards

Comprehensive cardiovasular system flashcards covering heart development, congenital defects, ECGs, valvular diseases, and pharmacology.

What are the five regions of the primitive heart tube in order from cranial to caudal?

Truncus arteriosus, Bulbus cordis, Primitive ventricle, Primitive atrium, and Sinus venosus.

What is the mnemonic for the five primitive heart tube regions?

'To Buy People A Smile'.

What does the truncus arteriosus eventually become?

The aorta and the pulmonary trunk.

What structure divides the truncus arteriosus and from which cells is it derived?

The spiral (aorticopulmonary) septum, which is derived from neural crest cells.

Failure of the spiral septum to divide the truncus arteriosus can lead to which two conditions?

Transposition of the Great Vessels or persistent Truncus Arteriosus.

Persistent truncus arteriosus is associated with which two syndromes?

Fetal alcohol syndrome and DiGeorge syndrome.

List the three primary acyanotic (Left-to-Right) congenital heart defects.

Ventricular Septal Defect (VSD), Atrial Septal Defect (ASD), and Patent Ductus Arteriosus (PDA).

List the '5 Ts' of cyanotic (Right-to-Left) congenital heart defects.

Tetralogy of Fallot, Transposition of Great Vessels, Truncus Arteriosus, Tricuspid Atresia, and Total Anomalous Pulmonary Venous Return (TAPVR).

What is the most common congenital heart defect overall?

Ventricular Septal Defect (VSD).

Which heart defect is the most common to present in adults, often as an incidental finding?

Atrial Septal Defect (ASD).

What is the single most high-yield physical exam finding for an Atrial Septal Defect (ASD)?

Fixed splitting of the $S_2$ heart sound.

In an Atrial Septal Defect (ASD), where is the characteristic oxygen saturation increase observed?

From the Superior Vena Cava (SVC) to the Right Atrium (RA).

What is a paradoxical embolus and how does it occur in ASD?

A Deep Vein Thrombosis (DVT) that travels from the Right Atrium to the Left Atrium through the defect, then to the brain, causing a stroke.

What are the indications to repair an Atrial Septal Defect (ASD)?

Pulmonary hypertension, Right Ventricular Hypertrophy (RVH), arrhythmia (Atrial Fibrillation), or paradoxical embolus.

What type of murmur is diagnostic for a Ventricular Septal Defect (VSD)?

A holosystolic (pansystolic) murmur at the lower left sternal border.

Why does a VSD murmur become louder at approximately 7 days of life?

Pulmonary Vascular Resistance (PVR) falls after birth, which increases the pressure gradient from the Left Ventricle to the Right Ventricle.

How is the size of a VSD related to the intensity of its murmur?

A smaller defect produces a louder murmur, often called 'maladie de Roger'.

In a VSD, where is the oxygen saturation step-up observed on a diagram?

At the level of the Right Ventricle (RV).

In a Patent Ductus Arteriosus (PDA), where does the oxygen saturation increase?

At the level of the pulmonary artery.

What happens to oxygen saturation in the aorta in Eisenmenger VSD?

The $pO_2$ decreases from the Left Ventricle to the aorta due to a Right-to-Left shunt reversal.

What is the pathophysiologic mechanism of Eisenmenger Syndrome?

A long-standing Left-to-Right shunt causes pulmonary hypertension and RVH, leading to shunt reversal (Right-to-Left) and cyanosis.

What are the three clinical findings associated with the development of Eisenmenger Syndrome?

Cyanosis, clubbing, and polycythemia.

Which mediator is key in the development of pulmonary hypertension in Eisenmenger Syndrome?

Endothelin-1.

What are the four components of Tetralogy of Fallot (PROVe)?

Pulmonary stenosis, Right Ventricular Hypertrophy (RVH), Overriding aorta, and Ventricular Septal Defect (VSD).

Which component of Tetralogy of Fallot determines the patient's prognosis?

Pulmonary stenosis.

What is the classic Chest X-ray finding for Tetralogy of Fallot?

A boot-shaped heart.

Why do patients with Tetralogy of Fallot squat to relieve 'tet spells'?

Squatting increases Systemic Vascular Resistance (SVR), which decreases the Right-to-Left shunt and improves oxygenation.

Which syndrome is associated with a harsh systolic murmur, hypocalcemia, and immune deficiency?

DiGeorge syndrome.

What is the anatomical defect in Transposition of Great Vessels?

The aorta exits the Right Ventricle and the Pulmonary Artery exits the Left Ventricle, creating two parallel circuits.

What is the classic Chest X-ray finding for Transposition of Great Vessels?

An egg-on-a-string appearance.

What medication is used to maintain a Patent Ductus Arteriosus (PDA) in cyanotic heart disease?

Prostaglandin $E_1$.

What is the characteristic murmur of a Patent Ductus Arteriosus (PDA)?

A continuous machinery-like murmur, best heard in the left infraclavicular region.

Which medication is used to pharmacologically close a Patent Ductus Arteriosus (PDA)?

Indomethacin (a non-selective NSAID).

What are two clinical associations with Patent Ductus Arteriosus (PDA)?

Congenital rubella and bounding pulses (wide pulse pressure).

Which heart defect is classically seen in Trisomy 21 (Down syndrome)?

Atrioventricular septal defect (AVSD) or endocardial cushion defect.

Where does narrowing classically occur in the adult (postductal) type of Coarctation of the Aorta?

At the ligamentum arteriosum.

What are the clinical findings of Coarctation of the Aorta?

Upper extremity hypertension, weak or absent femoral pulses, and cold lower extremities.

What causes 'rib notching' on a Chest X-ray in patients with Coarctation of the Aorta?

Erosion of the ribs by dilated intercostal collateral arteries.

What are the two major associations with Coarctation of the Aorta?

Turner syndrome ($45XO$) and bicuspid aortic valve.

The ductus arteriosus becomes which adult remnant?

Ligamentum arteriosum.

The foramen ovale becomes which adult remnant?

Fossa ovalis.

The ductus venosus becomes which adult remnant?

Ligamentum venosum.

The umbilical vein becomes which adult remnant?

Ligamentum teres hepatis (round ligament).

The umbilical arteries become which adult remnants?

Medial umbilical ligaments.

What physiological change causes the foramen ovale to close after birth?

Lungs expand, decreasing PVR, which makes Left Atrium pressure greater than Right Atrium pressure.

What is Ebstein anomaly and what prenatal exposure is it associated with?

Malformation of tricuspid valve leaflets (tricuspid regurgitation); associated with lithium exposure.

Which adult structures are derived from the 3rd aortic arch?

Common and proximal internal carotid arteries bilaterally.

What does the left 4th aortic arch become?

The aortic arch.

What does the right 4th aortic arch become?

The proximal right subclavian artery.

Which structures are derived from the 6th aortic arch?

Bilateral pulmonary arteries and the left-sided ductus arteriosus.

What are the three layers of the heart wall?

Epicardium (visceral pericardium), myocardium, and endocardium.

What is the composition of the fibrous pericardium?

A tough outer layer attached to the diaphragm and great vessels.

What are the three components of Beck's triad for cardiac tamponade?

Hypotension, Jugular Venous Distention (JVD), and muffled heart sounds.

What ECG findings are characteristic of cardiac tamponade?

Electrical alternans (alternating QRS height) and low-voltage QRS complexes.

Define Pulsus Paradoxus as seen in cardiac tamponade.

A drop in Systolic Blood Pressure (SBP) greater than $10\,mmHg$ during inspiration.

What JVP finding is a hallmark of cardiac tamponade?

Absent y-descent.

What is the classic ECG finding for acute pericarditis?

Diffuse saddle-shaped ST elevation in all leads and PR depression.

What is the first-line treatment for acute pericarditis?

NSAIDs and colchicine.

How is Dressler syndrome distinguished from post-MI fibrinous pericarditis?

Post-MI fibrinous pericarditis occurs within days via direct inflammation; Dressler syndrome occurs 2-6 weeks post-MI and is autoimmune.

What is the Kussmaul sign and in what condition is it classically seen?

A paradoxical rise in JVP on inspiration; seen in constrictive pericarditis.

Which heart valve is the only bicuspid (two-cusped) valve?

The mitral valve (all others are tricuspid).

What is the intrinsic firing rate and location of the SA node?

$60-100\,bpm$; located at the junction of the SVC and the Right Atrium.

What is the intrinsic firing rate and location of the AV node?

$40-60\,bpm$; located inferior to the coronary sinus opening in the interatrial septum.

Rank the conduction system components from fastest to slowest conduction speed.

Purkinje > Atria > Ventricles > AV node.

Which structure is found in the anterior mediastinum of children but not adults?

The thymus.

What are the primary contents of the posterior mediastinum?

Esophagus, descending aorta, thoracic duct, azygos vein, and sympathetic trunk.

What territory is supplied by the Left Anterior Descending (LAD) artery?

Anterior Left Ventricle wall, anterior 2/3 of the interventricular septum, apex, and anterolateral papillary muscle.

What territory is supplied by the Left Circumflex (LCx) artery?

Lateral and posterior Left Ventricle wall and the Left Atrium.

The Right Coronary Artery (RCA) supplies the AV node in what percentage of people?

$85\%$.%.

ST elevation in leads II, III, and aVF indicates an MI in which wall and artery?

Inferior wall; Right Coronary Artery (RCA).

ST elevation in leads $V_1-V_4$ indicates an MI in which wall and artery?

Anterior wall; Left Anterior Descending (LAD).

Why are nitrates contraindicated in an inferior wall MI?

The Right Ventricle is preload-dependent; nitrates drop preload, which can cause severe hypotension.

What defines coronary dominance?

Which artery (RCA or LCx) gives rise to the posterior descending artery (PDA).

Into which chamber does the coronary sinus drain?

The Right Atrium.

During which phase of the cardiac cycle are coronary arteries primarily perfused?

Diastole.

What is the primary autoregulator and mediator of cardiac pain during ischemia?

Adenosine.

In cardiac histology, what is the function of gap junctions within intercalated discs?

Electrical coupling to allow rapid spread of action potentials.

In cardiac histology, what is the function of desmosomes?

Mechanical coupling to prevent cells from pulling apart during contraction.

Where are sinusoidal (discontinuous) capillaries found?

Liver, spleen, and bone marrow.

Which type of capillary forms the Blood-Brain Barrier (BBB)?

Continuous capillaries.

What ion is responsible for Phase 0 (rapid depolarization) of the ventricular action potential?

Fast $Na^+$ influx.

What causes the Phase 2 'plateau' in the ventricular action potential?

$Ca^{2+}$ influx (L-type) balanced by $K^+$ efflux.

What is the clinical significance of the Phase 2 plateau?

It creates a long refractory period that prevents tetanic contraction.

Which ion current is responsible for 'pacemaker' activity in the SA node during Phase 4?

The funny current ($I_{f}$), a mixed $Na^+$/$K^+$ current.

Which drug specifically blocks the funny current ($I_{f}$)?

Ivabradine.

What does the CARD mnemonic for cardiac oxygen demand stand for?

Contractility, Afterload, Rate, and Diameter of the ventricle.

During which phase of the cardiac cycle is myocardial oxygen demand the highest?

Isovolumetric contraction.

State the Frank-Starling Law mechanism.

Increased preload leads to more optimal actin-myosin overlap, resulting in greater cross-bridge formation and force of contraction.

What are the formulas for Stroke Volume (SV) and Ejection Fraction (EF)?

$SV = EDV - ESV$ and $EF = (SV / EDV) \times 100$.

What is the formula for Mean Arterial Pressure (MAP)?

$MAP = CO \times SVR = DBP + \frac{1}{3}(SBP - DBP)$.

A wide pulse pressure is characteristic of which two conditions?

Aortic Regurgitation (AR) and Patent Ductus Arteriosus (PDA).

What does the 'a' wave on a Jugular Venous Pressure (JVP) waveform represent?

Atrial contraction.

What does a prominent 'v' wave on a JVP waveform suggest?

Tricuspid Regurgitation (TR).

What event defines the start of isovolumetric contraction?

Closure of the mitral and tricuspid valves ($S_1$).

What event defines the start of isovolumetric relaxation?

Closure of the aortic and pulmonic valves ($S_2$).

When does the mitral valve open?

When Left Ventricular pressure falls below Left Atrial pressure.

What is the opening snap (OS) in mitral stenosis?

The sound of the mitral valve opening, heard after $S_2$ and before the diastolic rumble.

Which two murmurs are the unique exceptions that worsen with DECREASED volume (Valsalva/standing)?

Mitral Valve Prolapse (MVP) and Hypertrophic Obstructive Cardiomyopathy (HOCM).

What clinical state does a loud $P_2$ heart sound indicate?

Pulmonary hypertension.

Describe the clinical profile of Aortic Stenosis (AS).

Crescendo-decrescendo systolic murmur at the Right Upper Sternal Border that radiates to the carotids.