TVD

Question 1

Gross path lesions TV atresia

Answer 1

• Absence of connection btw morphologic RA and RV

o Imperforated TV membrane in 5% of cases

• Complete agenesis/absence of TV → no communication btw RA and RV
  o RV hypoplasia
  o Absent inlet portion of RV

Question 2

Pathophys TV atresia

Answer 2

systemic venous return → RA → ASD → LA → mixes w pulmonary venous return → single AV valve → LV → systemic and pulmonary circulations
o Functionally univentricular heart

• Normal GA: blood flows from RA → ASD → LA
  o If VSD: will provide pulmonary blood flow (LV → VSD → RV → PA)
   Large VSD: pulmonary overcirculation and ↓ systemic blood flow
• TGA: pulmonary overcirculation → L-CHF
• No obstruction to pulmonary blood flow →larger volume of pulmonary venous return → high systemic O2
  o If RVOTO and ↓ pulmonary blood flow → systemic hypoxemia

Question 3

Anatomic features always present w/ TV atresia

Answer 3

 Absence of connection btw physiologic RA and RV
 Hypoplasia of morphologic RV
 Interatrial communication: PFO or ASD
 Morphologic LV w morphologic MV

Question 4

Anatomic features sometimes present w/ TV atresia

Answer 4

 Transposition of GAs
 Pulmonary stenosis
 Size of coexisting VSD: need communication btw systemic and pulmonary circulation
* Occasionally PDA with pulmonary atresia

Question 5

Goal of sx correction TV atresia

Answer 5

separation of systemic and pulmonary circuits
 Provide adequate pulmonary blood flow → ↓ hypoO2
 Prevent pulmonary overcirculation/PH → can lead to LV failure
 Preserve PA anatomy for later sx

Question 6

Sx correction if no concurrent TGA TV atresia

Answer 6

 Systemic to pulmonary shunt performed at 6-8wks
 Primary bidirectional Glenn procedure in older children
* Classic Glenn’s shunt = CrVC → RPA
* No volume/pressure overload of single ventricle compared to systemic-PA shunting
* Provide venous flow to lungs for oxygenation and improve O2 saturation

Question 7

Sx correction if concurrent TGA TV atresia

Answer 7

 Early palliation
* Pulmonary artery banding → ↓ pulmonary blood flow
* Norwood stage 1 procedure if severe stenosis and hypoplastic Ao
 Fontan procedure: only if good ventricular fct, unobstructed systemic blood flow and minimal AV valve regurgitation
* Diversion of systemic venous return → PA bypassing RV
* Definitive palliative sx tx if biventricular repair is not possible
* Ideally: younger, ↓PVR/PAP, adequate PA diameter, normal RA, systemic venous connections, sinus rhythm
o If ↑ venous or RAP → ↑ mean PAP → pleural effusion
o If ↑PVR/PAP → ↓ forward flow → ↓ L side filling → ↓ CO
 Fenestrations btw systemic venous atrium (RA) and pulmonary venous atrium (LA) = safety valve to ensure adequate LV filling
 Total cavopulmonary anastomosis
* Tunnel in RA directing caval blood → PA through anastomosis on underside RPA
* Eliminate diated systemic venous reservoir w ↑ RAP

Question 8

Histo TV atresia

Answer 8

o Fibrofatty tissue interposed btw muscular RA floor and parietal wall of ventricular mass in 95% of cases

Question 9

Size/development of trabecular portion of RV is variable in TV atresia and depend on

Answer 9

 Depend on presence/size of VSD → ↑ development if VSD present
 If no VSD: PDA provides pulmonary blood flow

Question 10

Survival in TV atresia depend on

Answer 10

ASD/PFO: allow blood flow from RA → LA

Question 11

Types of TV atresia

Answer 11

o I – Normally related GA
 Ia: no VSD + PA atresia
 Ib: VSD + PS
 Ic: VSD + no PS
o II – D-TGA
o III – L-TGA

Question 12

TV atresia: Hemodynamics and c/s determined by presence/absence of

Answer 12

o PV atresia
o Severity of subpulmonary/PS
o Relationship of GA
o Subaortic obstruction

Question 13

C/s TV atresia

Answer 13

o Cyanosis
o CHF signs
o ↓ growth

Question 14

PE TV atresia

Answer 14

low frequency holosystolic murmur form VSD

Question 15

ECG TV atresia

Answer 15

1st AVB

Question 16

CTX TV atresia

Answer 16

• Pulmonary overcirculation
• Normal cardiac silhouette

Question 17

Echo TV atresia

Answer 17

• Absent TV, no flow across RV inlet
  o Imperforated linear density at TV location
• Discordant ventricular chamber sizes
  o Small/absent RV
  o RAE
• ASD
• +/- VSD
• +/- LVE if pulmonary overcirculation

Question 18

TVD: gross exam

Answer 18

• Abnormal TV
  o Malformation of TV leaflets, chordae tendinea and pap muscles
   Focal/diffuse thickening of valve leaflets
• Irregular thickening w fenestrations
• Septal leaflet directly adhered to wall
• Direct papillary muscle attachment
• Elongated leaflets
   Underdevelopment of chordae tendinea/pap muscles
• Short/absent chordae
  o Incomplete separation of valve components from ventricular wall
  o Focal agenesis of valvular tissue
• Fusion of papillary muscles
• Fibrinous epicarditis around RA
• PFO

Question 19

TVD: pathophys

Answer 19

• TR → R sided volume overload
  o RAE and RVE
  o ↑ R sided pressures: potential for R → L shunt if concurrent shunting defects

Question 20

TVD: signalment

Answer 20

o Breeds: Labradors, English Sheepdogs, Great Danes, German Shepherds, Irish Setters
 Cats: Chartreux
o Usually young
o Common concurrent congenital defects: MVD, VSD, ASD, PS, AVSD

Question 21

TVD: c/s

Answer 21

most are asymptomatic until develop R CHF

Question 22

TVD PE

Answer 22

o Holosystolic R apical murmur
 Intensity does not correlate well with severity of TR
o R sided CHF: ascites

Question 23

ECG TVD

Answer 23

• Ventricular pre-excitation: AP (WPW)
• Splintered QRS
• Atrial arrhythmias → Afib most common
• R axis deviation from R sided enlargement
  o Deep S waves in lead I, II, III, aVF
• Tall/peaked P waves

Question 24

CTX TVD

Answer 24

• R sided cardiomegaly, RAE
• Marked apex shifting to L

Question 25

2D Echo TVD

Answer 25

o Abnormal location, shape, attachment, motion of TV apparatus  Adherence of septal leaflet to IVS  Large mural leaflet  ↓ valvular motion  Thickened leaflets o Large fused papillary muscles, malpositioning o RAE/RVE  RAE is marked vs RVE o ↓ L sided parameters from reduced RV SV

Question 26

Doppler echo TVD

Answer 26

TR

Question 27

Contrast echo TVD

Answer 27

bubbles remain in R heart for prolonged period o Can see bubbles in hepatic veins

Question 28

Cardiac KT angio TVD

Answer 28

o Dilated RV o TR o Dilated RA

Question 29

Physiology TVD

Answer 29

o Malformation of TV → TR → ↑ RA volume → RVEH → ↑ RV diastolic volume/dilation o RVEH → annular diation → worsens TR o ↑RAP → ↑ systemic venous P → ascites o ↓ forward pulmonary flow → ↓ volume to L heart → ↓ systemic CO

Question 30

Natural history TVD

Answer 30

* Can have multiple congenital defects: ASD, PS, ventricular pre excitation * Supportive treatment * Lesions usually tolerated for many years o Progressive valve dysfct o Cardiomegaly, arrhythmias

Question 31

Ebsteins etiology

Answer 31

* From failure of delamination from ventricular myocardium = adherent * Rare in dogs, not reported in cats

Question 32

Gross exam Ebsteins

Answer 32

* Basal attachment of TV displaced apically into RV o Normal mural leaflet or displaced o Septal leaflet apically displaced  Arise from RV myocardium * Atrialized portion of RV * Poor motion of valve leaflet

Question 33

Pathiphys ebsteins

Answer 33

* Severe TR, similar to severe TVD * RV dysfct: abn myocardial structure and fct o Atrialized RV is thin and dysfunctional * Smaller RV volume

Question 34

ECG ebsteins

Answer 34

* RBBB frequent * ↑PR * Pre-excitation

Question 35

Cardiac KT dx ebstein

Answer 35

* EGM (intracardiac ECG) = confirms from where the electrical activity comes from * RA pressures w/ simultaneous ventricular electropotentials on intracardiac ECG o When ECG close to TV = ventricular action potential. o When ECG more up in atrium = atrial action potential.

Question 36

Uhl anomaly

Answer 36

* Absence of RVFW myocardial layer * Apoptosis/ no cell development of myocytes * Reported in DSH

Question 37

TVS: gross exam

Answer 37

* Abnormal TV leaflets o Thickened leaflets o Commissural fusion o Short chordae * Annulus may be large * Hypoplastic/atretic RV o Unless associated VSD

Question 38

Pathophys TVS

Answer 38

* ↑ resistance to blood flow from RA → RV o PG across TV leads to RAE o R-CHF