Ep-PAINE-nym



Purkinje Fibers

Other Known Aliases subendocardial branches

Definitionspecialized conducting fibers composed of electrically excitable cells located just beneath the subendocardium in the inner ventricular walls of the heart

Clinical Significance these cells actually conduct cardiac action potentials faster and more effeciently than any other cells in the heart and are responsible for the synchronized contractions of the ventricles during depolarization. They also have intrinsic pacemaking ability at 20-40 bpm to act as a back-up pacing system.

HistoryNamed after Jan Evangelista Purkinje (1787-1869), a Czech anatomist and experimental physiologist who received his medical doctorate from Charles University in Prague in 1818. He would be appointed Professor of Physiology in Breslau in 1823 and did revolutionary work on vision. He would later create the world’s first Department of Physiology at the University of Breslau in Prussia in 1839 and the world’s second official physiology lab in 1842. During his career of physiologic discovery and research, he discovered large neurons with branching dendrites in the cerebellum (Purkinje cells), describe the change in brightness of red and blue colors as light intensity decreases (Purkinje shift), and the eye’s reduced sensitivity to dim red light compared to dim blue light (Purkinje effect). He also was the first scientist to present work on the cellular theory of biology, the first to use the term “protoplasm” to describe the fluid in cells, and the first to report on the individuality of fingerprints. But it was in 1839 when he described his eponymous fibers of the heart. He was one of the best known scientists of his era and was so famous, people would address letters to him and simply put “Purkinje, Europe”.


References

  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com
  6. Cavero I, Guillon JM, Holzgrefe HH. Reminiscing about Jan Evangelista Purkinje: a pioneer of modern experimental physiology. Adv Physiol Educ. 2017; 41(4):528-538. [pubmed]

PAINE #PANCE Pearl – Cardiovascular



Question

74yo woman, with a history of CAD and hyperlipidemia, presents to your office with a 6-month history of leg pain and swelling. She states that it seems to be worse when she is on her feet and improves when she can put her legs up. She denies worsening pain with activity or walking, but has recently developed a “rash” on her legs that is worrying her (see below). Physical examination reveals warmth to the feet and legs with scattered, thin hair. You appreciate 1+ DP and PT pulses bilaterally.

  1. What are some bedside maneuvers or tests you can perform to differentiate between arterial and venous insufficiency?
  2. What are the findings associated with each?

Ep-PAINE-nym



Bundle of His

Other Known Aliases atrioventricular bundle

Definitioncollection of electrical conduction cells of the heart that transmit impulses from the AV node to the ventricles

Clinical Significance this bundle of cells is responsible for communication contraction impulses from the atria to the ventricles. Any damage to this area can result in varying degrees of heart block and conduction abnormalities

HistoryNamed after Wilhelm His Jr. (1863-1934), a Swiss-born cardiologist and anatomist who received his medical doctorate from the University of Leipzig in 1889. The son of the equally famous Basel anatomist Wilhelm His Sr., he would become professor extraordinaire at his alma mater 6 year after graduating. He also went on to be physician-in-chief at the Friedrichstadt Hospital in Dresden, chair of internal medicine in Berlin, and advisory internist for several armies during World War I. He would describe his eponymous bundle as an assistant professor in 1893.


References

  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com
  6. His Jr, W. Die Tätigkeit des embryonalen Herzens und deren Bedeutung für die Lehre von der Hezbewegung beim Menschen. Arbeiten aus der medidizinischen Klinik zu Leipzig, 1893: 23.

#68 – Bundle Branch Blocks



***LISTEN TO THE PODCAST HERE***



Review of the Electrical Conduction System of the Heart

  • Cardiac cells specialized to initiate and distribute electrical impulses in an orderly and sequential manner
  • Sinoatrial Node
    • Located in superior region of the crista terminalis
      • SVC feeds into the right atrium
    • Pacemaker of the heart and initiates the heartbeat
      • Starts in the node, spreads down the walls of the atria, until it reaches the AV node, stimulating contraction of the myocardium
    • Arterial Supply – SA nodal artery via the RCA
  • Atrioventricular Node
    • Located in interatrial septum above the coronary sinus near the attachment of the septal cusp of the tricuspid valve (Triangle of Koch)
    • Passes SA node impulse to the AV bundle (Bundle of His)
    • Arterial Supply – AV nodal artery via the RCA (80-90%) or LCx (10-20%)
  • AV Bundle (Bundle of His)
    • Arises from the AV node and descends along the membranous portion of the interventricular septum, where it divides at the upper border of the muscular portion of the interventricular septum into the left and right bundles suppling their respective ventricles
    • Transmits AV nodal impulses through the interventricular septum to the left and right bundle branches, which gives rise to the Purkinje fibers that ultimately distribute the ventricular myocardium

Bundle Branch Blocks Pearls

  • R-wave = depolarization going TOWARDS the lead
  • S-wave = depolarization going AWAY from the lead
  • RBBB = delay in conduction is oriented to the RIGHT and ANTERIOR
    • QRS = Positive V1 and negative V6
  • LBBB = delay in conduction is oriented to the LEFT and either ANTERIOR or POSTERIOR
    • QRS = Negative V1 and positive V6
  • Wide QRS complex > 120 ms
    • Delay in conduction due to the block
  • Secondary Repolarization (ST-T) Abnormalities
    • T-wave discordance with last deflection of QRS

Causes

  • RBBB
    • More common in patients without structural heart disease
    • Congenital
      • ASD
    • Cardiac
      • Valvulopathies, ischemic heart disease
    • Pulmonary
      • Pulmonary HTN, PTE
  • LBBB
    • 4 main underlying conditions
      • Coronary disease
      • Hypertensive heart disease
      • Aortic valve disease
      • Cardiomyopathies

RBBB EKG Diagnostic Criteria

  • QRS > 120 ms
    • If all other criteria met but QRS < 120 ms, it is termed incomplete RBBB
  • rSR’ pattern in V1 and V2
  • Slurred S-wave in lateral leads (I, aVL, V5, V6)
  • ST depression and T-wave inversion in V1-V3

LBBB EKG Diagnostic Criteria

  • QRS > 120 ms
  • Dominant S-wave in V1-V3
    • Moving away from the leads
  • Broad, monophasic (M-shaped or notched) R-wave in lateral leads (I, aVL, V5, V6)
    • Moving towards the leads
  • Appropriate discordance
    • ST-segment and T-wave are in OPPOSITE direction to the main vector of the QRS complex
  • Left axis deviation
  • Poor R-wave progression

SPECIAL CONSIDERATIONS


Fascicular Blocks

  • Anterior
    • Pathology
      • When blocked, the conduction to the high lateral portion of the ventricle is delayed
        • Spreads to the intact posterior fascicle and RBB
          • Causes left axis deviation
    • Criteria for left anterior fascicular block
      • QRS normal to slightly prolonged
      • Left axis deviation WITHOUT other reasons
      • Small R-wave and large S-wave in inferior leads (II, III, aVF)
      • Small Q-wave with large R-wave in lateral leads (I, aVL)
  • Posterior
    • Pathology
      • When blocked, the conduction to the inferior portion of the ventricle is delayed
        • Spreads to the intact anterior fascicle and RBB
          • Causes right axis deviation
    • Criteria for left posterior fascicular block
      • QRS normal to slightly prolonged
      • Right axis deviation WITHOUT other reasons
      • Small R-wave and large S-wave in lateral leads (I, aVL)
      • Small Q-wave and large R-wave in inferior leads (II, III, aVF)

Sgarbossa’s Criteria

  • Used in the presence of LBBB or paced rhythm to uncover potential ischemia
  • Original (1996)
    • Concordant ST elevation > 1mm in leads with a positive QRS complex (5 points)
    • Concordant ST depression > 1mm in V1-V3 (3 points)
    • Excessively discordant ST elevation > 5mm in leads with a negative QRS complex (2 points)
    • Score ≥ 3 has a specificity of 90% for detecting concomitant ischemia
  • Smith-Modified Sgarbossa Criteria (2012)
    • ≥ 1 lead with ≥ 1mm of concordant ST elevation
    • ≥ 1 lead of V1-V3 with ≥ 1mm of concordant ST depression
    • ≥ 1 lead ANYWHERE with ≥ 1mm ST elevation AND proportionally excessive discordant ST elevation
      • Defined as ≥ 25% of the depth of the preceding S-wave

1893 Cottage Physician

References

  1. Heart. In: Morton DA, Foreman K, Albertine KH. eds. The Big Picture: Gross Anatomy, 2e. McGraw-Hill; Accessed January 17, 2021.
  2. Jaffar A. Anatomical Structure of the Heart. In: Elmoselhi A. eds. Cardiology: An Integrated Approach. McGraw-Hill; Accessed January 17, 2021.
  3. Goldberger AL. Electrocardiography. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison’s Principles of Internal Medicine, 20e. McGraw-Hill; Accessed January 17, 2021.
  4. LITFL. Right bundle branch blocks. https://litfl.com/right-bundle-branch-block-rbbb-ecg-library/
  5. LITFL. Left bundle branch blocks. https://litfl.com/left-bundle-branch-block-lbbb-ecg-library/
  6. REBELEM. Bundle Branch Blocks. https://rebelem.com/bundle-branch-blocks101/
  7. Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators. N Engl J Med. 1996; 334(8):481-7. [pubmed]
  8. Smith SW, Dodd KW, Henry TD, Dvorak DM, Pearce LA. Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule. Ann Emerg Med. 2012; 60(6):766-76. [pubmed]
  9. Meyers HP, Limkakeng AT Jr, Jaffa EJ, et al. Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study. Am Heart J. 2015; 170(6):1255-64. [pubmed]
  10. CORE EM. Validation of Modified Sgarbossa Criteria. https://coreem.net/journal-reviews/modified-sgarbossa-criteria/

PAINE #PANCE Pearl – Cardiovascular



Question

62yo man, with a history of COPD and 52-pack-year history of smoking, presents to your office to establish care. His shortness of breath has been manageable using tiotropium daily with albuterol 2-3x per month for exacerbation. He denies angina, chest pain, or unreasonable dyspnea with exertion. An EKG was performed and is below.

  1. What does it show?
  2. What are the diagnostic criteria present?

Answer

  • The EKG reveals a right bundle branch block most likely due to his underlying COPD and pulmonary hypertension.
  • Diagnostic criteria for RBBB are:
    • Wide QRS > 120 ms
    • RSR’ pattern in V1-2 (“rabbit ears”) with R’ > R
    • Wide, slurred S wave in I, aVL, or V5-6
  • Other common findings, though not always associated, is ST depression and T wave inversion in the right precordial leads (V1-3)

Ep-PAINE-nym



Beck’s Triad

Other Known Aliases none

Definitionclassic physical examination findings associated with critical cardiac tamponade

Clinical Significance although not seen in every patient with cardiac tamponade, it is a common question on boards and certification examinations. These include: 1) hypotension, 2) JVD, and 3) muffled/distant heart sounds.

HistoryNamed after Claude Schaeffer Beck (1894-1971), an American cardiac surgeon who recieved his medical doctorate from Harvard University in 1921. He would attend surgical residency at Case Western University, where he would spend his entire career. He developed a novel re-circulation technique for cardiac ischemia called the Beck Procedure, where pectoral muscle was implanted in the pericardium, and later placing a vein graft between the aorta to the coronary sinus. He also pioneered the first successful use of a defibrillator in 1947 to restore ROSC in a 14yo patient he was operating on for a congenital heart defect. His eponymous triad was first described in 1935 in an article entitled “Two cardiac compression triads” in the Journal of the American Medical Association.


References

  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com
  6. Beck CS. Two Cardiac Compression Triads. JAMA. 1935;104(9):714-716. [link]
  7. Theruvath P, Ikonomidis JS. Historical perspectives of The American Association for Thoracic Surgery: Claude S. Beck (1894-1971). JTCVS. 2015;149(3):655-660. [link]

PAINE #PANCE Pearl – Cardiovascular



Question

62yo man, with a history of COPD and 52-pack-year history of smoking, presents to your office to establish care. His shortness of breath has been manageable using tiotropium daily with albuterol 2-3x per month for exacerbation. He denies angina, chest pain, or unreasonable dyspnea with exertion. An EKG was performed and is below.

  1. What does it show?
  2. What are the diagnostic criteria present?

Ep-PAINE-nym



Austin Flint Murmur

Other Known Aliases none

Definitionlow-pitched, rumbling, mid-to-late diastolic murmur heard best at the apex

Clinical Significance this murmur is associated with severe aortic regurgitation and is due to two distinct mechanisms. First, the aortic jet flow impinging on the mitral valve causing vibrations from premature closing and second, turbulence of two columns of blood from the left atrium to left ventricle and aorta to left ventricle.

HistoryNamed after Austin Flint I (1812-1886), an American physician who received his medical doctorate from Harvard University in 1833. He would practice in Boston, Buffalo (where he would help found the Buffalo Medical College, and New York City, where he was professor of medicine at the famed Bellevue Hospital. A proponent of European diagnostic methods (as he was mentored by James Jackson at Harvard, who was a follower of Laënnec), he advocated and popularized the use of the binaural stethoscope in physical diagnosis. He was a prolific writer and researcher with his Treatise on the Principles and Practice of Medicine considered as a classic medical text. He is also recognized as having coined the term “broncho-vesicular breathing” in lung auscultation. He would publish the first detailed description his eponymous murmur in 1862 in the American Journal of Medicine Sciences in an article entitled “On cardiac murmurs”.


References

  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Up To Date. www.uptodate.com
  6. Flint A. On cardiac murmurs. American Journal of Medical Science. 1862;7;29-54 [link]
  7. The Mitral Valve. Austin Flint. http://www.themitralvalve.org/mitralvalve/austin-flint

PAINE #PANCE Pearl – Pediatrics



Question

A 3yo girl is brought to your office by her parents for concern of asthma. They state that when she plays with her siblings, she often gets short of breath and needs to stop to rest for a few minutes. She is otherwise healthy and was born at 38 weeks gestation via cesarean section. She has had an uncomplicated past medical history and is up to date on all immunizations.

Physical examination reveals a well-nourished, well-developed girl, who is at 67% for height and 46% for weight for her age. Vital signs are BP-110/68, HR-87, RR-13, O2-100%, and temperature-98.7o. There is no evidence of cyanosis and auscultation findings are below.

  1. Describe what you hear.
  2. What condition is this most suggestive of?
  3. What is the management of this condition?

Answer

  1. Continuous, holosystolic, blowing mumur with a faint split S2

2. This type of murmur and the above clinical features are most likely due to a patent ductus arteriosus.

3. After a Doppler echocardiogram has been performed, surgery would be the next step to close this defect. Pharmacologic therapy does not work as well in older infants and children. Transcatheter closure would be the preferred option given the patient’s age.

#58 – Acyanotic Congenital Heart Defects



***LISTEN TO THE PODCAST HERE***



Click Here for Episode #11 – Review of Cyanotic Congenital Heart Defects



Review of In-Utero and Neonatal Cardiovascular Physiology

  • Ductus arteriosus
    • Connects the pulmonary artery to the descending aorta
    • Prostaglandin E2 are produced by the placenta and keep this open, along with low arterial oxygen concentration
    • Begins to close 10-15 hours after delivery and should be completed by 2-3 weeks of age
  • Foramen ovale
    • Communication between right and left atrium
    • Once the infant begins spontaneously breathing, increases in pulmonary blood flow and left atrial pressures mechanically seals the foramen ovale

Review of Initial Approach to Screening for Congenital Heart Diseases

  • The main approach to initial cardiac evaluation for infants with suspected heart disease is to determine:
    • Innocent vs Congenital Heart Disease
      • Cyanotic vs Acyanotic
      • Indications for emergent referral
  • Historical Clues
    • Symptomatic
      • Cyanosis, respiratory, poor growth, poor feeding, syncopal episodes
    • Family History
      • Parent or sibling with congenital heart disease
        • 1st degree relative with any CHD – RR 3.21
    • Genetic syndromes
    • Prenatal Evaluation
      • Abnormalities on prenatal ultrasound
      • Maternal factors that increase risk
        • Multifetal pregnancy, prematurity, preeclampsia, DM, HTN, Age > 40, alcohol/substance use, smoking,
    • Age of child
  • Physical Examination
    • Murmurs
      • Innocent murmur
        • ≤ Grade 2
        • Short systolic phase
        • Minimal radiation
        • Soft intensity
    • Extra Heart Sounds
      • Abnormal S2
      • S3 or S4
      • Systolic click
      • Thrills and heaves
    • Other Findings
      • Abnormal vital signs
        • BP differences between right arm, left arm, and legs
        • Weak or bounding pulses
      • Hepatomegaly
  • Diagnostic Studies
    • Pulse oximetry screening
      • Measure in right hand (pre-ductal) and either foot (post-ductal)
    • Chest radiograph
      • Cardiomegaly, increased pulmonary vascular markings, pulmonary edema
    • EKG
      • LVH, RVH, abnormal axis, dysrhythmias, prolonged QT
    • Echocardiogram
Up-to-Date. 2020

Ventricular Septal Defect

Epidemiology

  • 30% of all CHD (most common)

Normal Development

  • Three main components
    • AV canal septum (1)
    • Muscular septum (2)
    • Parietal band or distal conal septum (3)
  • Closure of the interventricular foramen is dependent on:
    • Right-sided endocardial cushions  projecting into the AV canal
    • Connective tissue growth on the crest of the muscular septum
    • Downward growth of ridges dividing the conus
Up-to-Date. 2020

Types

  • Membranous Defects
    • Most common clinically significant VSD
    • Under aortic valve and behind septal leaflet of the tricuspid valve
      • May extend into muscular septum
    • Can be associated with LVOTO and coarctation
  • Muscular Defects
    • Located along right ventricular free wall-septal junction, in the central muscular septum, or in the apical septum
    • Often close spontaneously
  • Malalignment Defects
    • Result from anterior/posterior malalignment of the conal septum
    • Associated with Tetralogy of Fallot
  • Subpulmonic Defects (outlet)
    • Superior and anterior conal septum defects
  • AV Canal Defects (inlet)
    • Posterior and superior to annulus of tricuspid valve
    • Associated with ASDs
Up-to-Date. 2020

Pathophysiology

  • Cause no problems in-utero
  • Causes a left-to-right shunt ex-utero
    • Higher left ventricular pressures
  • Categorization is based on:
    • Size
      • Small – < 4mm
      • Moderate – 4-6mm
      • Large – > 6mm
    • Shunt (Pulmonary:Systemic flow)
      • Small – Qp:Qs < 1.5
      • Moderate – Qp:Q 1.5-2.3
      • Large – Qp:Qs > 2.3
  • Effects on Circulation
    • Pulmonary
      • Increased and causes tachypnea and increased respiratory effort
    • Systemic
      • LV output must increase to maintain systemic flow
      • As systemic flow decreases (large VSDs):
        • Increased alpha-adrenergic stimulation
        • Increased catecholamine release
        • Increased angiotensin release
      • Increases risk of heart failure

Natural History

  • Small
    • 75% close spontaneously within 2 years of life
    • Those that persist in adulthood are benign
  • Moderate
    • Spontaneous closure depends on pulmonary arterial pressure and size/location of defect
    • Can respond to medical management
  • Large
    • Rarely spontaneously close
    • Surgery must be performed within 1st year to avoid permanent pulmonary vascular resistance

Clinical Presentation

  • Prenatal
    • Moderate to large VSD can be diagnosed during 20week ultrasound
  • Postnatal
    • Small VSD
      • Can be asymptomatic and present with only a murmur
    • Moderate to Large VSD
      • Present 3-4 weeks from birth with signs and symptoms of heart failure
        • Tachypnea
        • Poor feeding or poor weight gain
        • Tachycardia
        • Hepatomegaly
        • Rales, retractions
      • Cardiac Examination
        • Murmur
          • Harsh or blowing holosystolic
          • Heard best at 3rd-4th intercostal space
          • May have a diastolic rumble
            • Increased flow across mitral valve
          • Loud, splitting of S2
            • Due to increased pulmonary arterial pressure
        • Palpable thrill may be present

Diagnostic Studies

  • EKG
    • LVH, RVH, RAE
  • Chest Radiograph
    • Increased pulmonary vascular markings
  • Echocardiography
    • Two-dimensional Doppler confirms diagnosis
Radiopaedia

Management

  • Expectant
    • Most small VSD close spontaneously
    • Follow-up every 6 months with cardiologist until murmur resolves or yearly if murmur persists but still asymptomatic
  • Medical
    • Heart failure management
      • Diuretics are first line
    • Nutritional support
    • Pulmonary hypertension management
      • May need cardiac catheterization for accurate measurements and determination for surgical management
  • Surgical
    • Indications
      • Persistent symptoms with maximal medical therapy
      • Moderate/large defects with pulmonary hypertension
      • Persistent left-to-right shunt with LV dilation
      • Associated aortic valve prolapse or aortic regurgitation
      • Double-chambered right ventricle
    • Direct patch closure is procedure of choice in most children
    • Transcatheter closure is technically challenging and not offered routinely due to higher incidence of AV block and valve injury

Atrial Septal Defect

Epidemiology

  • 10-15% of all CHD
  • 1-2 per 1000 live births

Normal Development

  • Begins at 5th week and is made up of 3 structures
    • Septum primum and AV canal septum (endocardial cushions)
      • Arises from superior portion of common atrium
      • Grows caudally towards AV canal septum
        • These two fuse close ostium primum between right and left atria
    • Septum secundum
      • Covers the ostium secundum on the right atrial side of the septum primum
        • Forms the fossa ovalis
      • Leaves a small opening in-utero
        • Foramen ovale
          • Held open due to pressure gradients between the higher right atria and lower left atria
            • Allows for right to left flow
Up-to-Date. 2020

Types

  • Primum Defect
    • 15-20% of ASDs
    • Occurs when primum septum does not fuse with endocardial cushions
  • Secundum Defect
    • 70% of ASDs
    • 2x more common in females
    • Located within the fossa ovalis
  • Sinus Venosus Defect
    • 5-10% of ASDs
    • Malposition of the insertion of the superior or inferior vena cava on the atrial septum
  • Patent Foramen Ovale
    • Identified on 30% of adult autopsies
    • NOT considered an ASD because no septal tissue is missing
Up-to-Date. 2020

Natural History

  • Most close spontaneously
    • >80% of small (<5mm)
    • 30-60% of moderate (6-10mm)
    • Large (>10mm) do not close spontaneously
  • Persistent ASDs can cause pulmonary hypertension and heart failure in adulthood

Clinical Presentation

  • Most are asymptomatic and diagnosed only by identification of murmur
  • Murmur
    • Midsystolic pulmonary flow or ejection murmur
      • Heard best left 2nd intercostal space
    • Wide, fixed split S2
      • ASD equalizes the respiratory effect on both right and left ventricular output
      • If pulmonary hypertension is present, there may be an accentuated pulmonic component of S2
    • May have associated mitral regurgitation murmur

Diagnostic Studies

  • EKG
    • May show rSr’ or rsR’ pattern in V1
      • Incomplete RBBB
  • Echocardiogram
    • Transthoracic may see, but a transesophageal is better

Management

  • Often watch until child is 2yo as most will spontaneous
    • Even persistent defects are not recommended to close
  • Closure Indications
    • Right heart enlargement
    • Pulmonary overcirculation
    • Substantial left-to-right shunt
  • Types of Closures
    • Percutaneous
      • Criteria
        • < 30mm is diameter
        • ≥ 5mm or rim tissue around defect sufficient for effective closure without obstructing surrounding structures
      • Avoids bypass and major surgical incisions
      • Complications
        • Device embolization, malposition, dysrhythmias, cardiac perforation
    • Surgery
      • Indications
        • Sinus venosus defects
        • Coronary sinus defects
        • Primum ASDs
        • Large ASDs with heart failure
      • Closed with pericardial or Dacron patch

Atrioventricular Septal Defect

Epidemiology

  • 4-5% of CHD
  • 0.3-0.4 per 1000 live births
  • Up to a 50% risk of trisomy 21

Normal Development

  • Primitive AV canal connects the atria with the ventricles
  • At 4-5 weeks gestation, the superior and inferior endocardial cushions fuse and form the AV canal
    • This contributes to the AV valves and septum

Types and Classifications

  • Classified based on the degree of the defect
    • Complete
      • Complete failure of fusion between the superior and inferior endocardial cushions
        • Combined primum ASD and posterior VSD with a single, common AV valve
      • Can be balanced (both ventricles get same flow) or unbalanced (one gets more than the other)
        • Unbalanced can lead to hypoplasia
    • Partial
      • Incomplete fusion of superior and inferior endocardial cushions
        • Primum ASD, single AV valve annulus with 2 valve orifices
    • Transitional
      • Large primum defect, cleft mitral valve, and inlet VSD
Up-to-Date. 2020
  • Rastelli Classification
    • Type A
      • Most common form and most common ASVD with Down syndrome
    • Type B
      • Least common
    • Type C
      • Frequently found with other conditions
        • Tetralogy of Fallot, Transposition of Great Vessels
Up-to-Date. 2020

Pathophysiology

  • Complete AV Canal Defect
    • Increased pulmonary blood flow due to left-to-right shunting
      • Leads to heart failure and pulmonary hypertension
  • Partial AV Canal Defect
    • Volume overload of right atrium and right ventricle with pulmonary overcirculation due to left-to-right shunting
      • No pulmonary hypertension
    • Mitral regurgitation can be severe
  • Transitional AV Canal Defect
    • Shunting often mild due to small VSD

Clinical Presentation

  • In-Utero
    • Can be diagnosed early during pregnancy
    • Rarely cause any fetal distress or growth disturbances
  • Complete
    • Heart failure develops early in infancy
      • Tachypnea, poor feeding, poor growth, sweating, and pallor by 2 month
      • Severity of symptoms depends on size and degree of AV valve regurgitation
    • Physical examination
      • Hyperactive precordium with inferior/laterally displaced PMI
      • Increased S2
      • Systolic ejection murmur heard best at left upper sternal border
  • Partial and Transitional
    • Asymptomatic during childhood and only diagnosed on routine examination
    • Physical examination
      • Wide and fixed S2 during respiration
      • Systolic ejection murmur heard best at left upper sternal border
        • Diastolic rumble may be heard
        • Holosytolic murmur of MR

Diagnostic Studies

  • Echocardiography
    • Transthoracic is adequate
    • Apical four chamber or subcostal view is best to see defect

Management

  • In general, surgical correction is recommended because of significant morbidity and mortality of the pulmonary circulation effects
  • Complete
    • Correction by 6 months of age to prevent permanent pulmonary hypertension
    • Close the ASD and VSD and create to separate, competent AV valves
      • Single-patch or double-patch
Up-to-Date. 2020
  • Partial and Transitional
    • Primum ASD does not close spontaneously and leaves the patient at risk for atrial fibrillation and heart failure later in life
    • Surgical goal is to close intraatrial communication and restore/preserve AV valve competence
      • Patch closure of ostium primum defect and mitral valvuloplasty
    • Timing is usually between 18 months and 3 years

Patent Ductus Arteriosus

Epidemiology

  • 3-8 per 10,000 live births
  • 2:1 female predominance

Normal Development

  • Derived from the embryonic left sixth arch
  • Actually has different tissue than the aorta or pulmonary artery
    • Intima is thicker
    • Media contains more smooth muscle
  • In utero, allows from RV flow to placenta to get oxygenated
  • Keep open by low arterial oxygen and prostaglandin E2 from placenta
  • At birth, increased levels of arterial oxygen and the lack of prostaglandin E2 begins the process of spontaneous closure

Clinical Presentation

  • Symptoms depend on the degree of left-to-right shunting
    • Dependent on size and length of PDA, as well as the difference between the pulmonary and systemic vascular resistances
  • Classic murmur
    • Continuous, holosystolic murmur
      • Machinery murmur
    • Heard best over left upper sternal border
  • Small (Qp:Qs < 1.5 to 1)
    • Asymptomatic and detected on routine physical examination
  • Moderate (Qp:Qs 1.5-2.2 to 1)
    • May present with exercise intolerance and heart failure
      • Left-to-right shunt increasing left atrial and ventricular volume
        • Progress to left ventricular dilation and dysfunction
    • Displaced PMI
    • Widened pulse pressure
  • Large (Qp:Qs > 2.2 to 1)
    • Due to increased left sided pressures, can lead to increased pulmonary pressures
      • May be irreversible if not corrected
      • Can lead to right-to-left shunt if pressure is high enough
        • Eisenmenger syndrome (cyanosis)
      • Split S2 with prominent pulmonary component
      • Murmur may disappear as pulmonary pressure increases
    • Heart failure, poor feeding, failure to thrive, respiratory distress
    • Dynamic PMI with a thrill
    • Wide pulse pressures and bounding pulses

Diagnostic Studies

  • Transthoracic, doppler color flow echocardiography
    • The ductus is best viewed on the parasternal short-axis and suprasternal view

Management

  • Decisions are made on whether to actively close the PDA or monitor cardiac status
    • Term vs pre-term
      • Pre-term respond well to prostaglandin inhibitors
    • Size of the PDA
      • Moderate to large warrant closure
      • Small, audible PDA also benefit from closure to lower long term complications
        • Especially bacterial endocarditis
    • Degree of left-to-right shunt
    • Degree of left sided volume overload
    • Evidence of pulmonary hypertension
      • Closure not recommended in severe PAH
  • Closure Options
    • Medical/Pharmacologic Therapy
      • Prostaglandin inhibitors
        • Indomethacin, ibuprofen
          • Ibuprofen > indomethacin in term infants and older patients
    • Surgery
      • Posterolateral thoracotomy with direct PDA ligation
      • Video-Assisted Thoracoscopic Surgery (VATS) is less invasive option
        • Not indicated if PDA size > 9mm
      • Percutaneous closure using coils or commercial occlusion devices

Coarctation of the Aorta

Definition

  • Narrowing of the descending aorta at the insertion of the ductus arteriosus distal to the left subclavian artery

Epidemiology

  • 4-6% of all CHD
  • 4 cases per 10,000 live births
  • More common in males

Pathogenesis

  • Unknown, but two theories prevail:
    • Decreased intrauterine blood flow leading to under development of the fetal aortic arch
    • Migration/extension of ductal tissue into the wall of thoracic aorta
  • Genetic associations and increased familial risk
  • Usually accompanied with other CHD

Pathophysiology

  • As PDA and FO begin to close after birth, increased pressure over the narrowed aorta
    • Leads to left ventricular outflow tract obstruction
    • Increased collateral blood flow across the intercostals, internal mammary, and scapular vessels

Clinical Manifestations

  • Classic findings
    • Absent/delayed femoral pulses
    • Difference in upper extremity and lower extremity blood pressures
  • Neonates
    • Asymptomatic as long as there is a patent ductus
    • Murmurs of other CHD
  • Infants and Older Children
    • Complain of lower extremity claudication symptoms with exertion
    • Hypertension may be prominent
  • Adults
    • Hypertension is may sign
      • If severe, may lead to heart failure, aortic pathologies
    • Claudication can also be present

Diagnostic Studies

  • Chest radiography
    • Infants
      • Cardiomegaly with increased pulmonary vascular markings
    • Older children and adults
      • Rib notching from large collateral development
      • “3” sign from indentation of aortic wall at coarctation site
The red arrows point to rib notching caused by the dilated intercostal arteries. The yellow arrow points to the aortic knob, the blue arrow to the actual coarctation and the green arrow to the post-stenotic dilation of the descending aorta. Learning Radiology. 2020
  • Echocardiography
    • Transthoracic, doppler flow can visualize coarctation and evaluate for other defects
    • Ideal view is high parasternal long axis or suprasternal view
  • Cardiovascular MRI/CT
    • Recommended for adolescent and adult patients
  • Cardiac catheterization
    • Generally performed in conjunction with therapeutic interventions, or in adults with associated coronary disease

Management

  • Indications for inventions
    • Neonates with critical coarctation
      • Emergent medical therapy
        • Continuous infusion of prostaglandin E1
        • Inotropic support
        • Support care to correct metabolic derangements
    • Gradient > 20 mmHg
    • Radiologic evidence of clinically significant collateral flow
    • Hypertension or heart failure attributed to the defect
  • Types of Interventions
    • Balloon angioplasty (only)
      • Infants > 4 months and young children < 25kg
      • Preferred therapy for isolated coarctation
    • Stent Placement (after angioplasty)
      • Children > 25kg and adults
    • Surgical repair
      • Falling out of favor with increasing advancement and safety of transcatheter techniques



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