TVD Flashcards
Gross path lesions TV atresia
- 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
Pathophys TV atresia
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
Anatomic features always present w/ TV atresia
Absence of connection btw physiologic RA and RV
Hypoplasia of morphologic RV
Interatrial communication: PFO or ASD
Morphologic LV w morphologic MV
Anatomic features sometimes present w/ TV atresia
Transposition of GAs
Pulmonary stenosis
Size of coexisting VSD: need communication btw systemic and pulmonary circulation
* Occasionally PDA with pulmonary atresia
Goal of sx correction TV atresia
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
Sx correction if no concurrent TGA TV atresia
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
Sx correction if concurrent TGA TV atresia
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
Histo TV atresia
o Fibrofatty tissue interposed btw muscular RA floor and parietal wall of ventricular mass in 95% of cases
Size/development of trabecular portion of RV is variable in TV atresia and depend on
Depend on presence/size of VSD → ↑ development if VSD present
If no VSD: PDA provides pulmonary blood flow
Survival in TV atresia depend on
ASD/PFO: allow blood flow from RA → LA
Types of TV atresia
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
TV atresia: Hemodynamics and c/s determined by presence/absence of
o PV atresia
o Severity of subpulmonary/PS
o Relationship of GA
o Subaortic obstruction
C/s TV atresia
o Cyanosis
o CHF signs
o ↓ growth
PE TV atresia
low frequency holosystolic murmur form VSD
ECG TV atresia
1st AVB
CTX TV atresia
- Pulmonary overcirculation
- Normal cardiac silhouette
Echo TV atresia
- 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
TVD: gross exam
- 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
TVD: pathophys
- TR → R sided volume overload
o RAE and RVE
o ↑ R sided pressures: potential for R → L shunt if concurrent shunting defects
TVD: signalment
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
TVD: c/s
most are asymptomatic until develop R CHF
TVD PE
o Holosystolic R apical murmur
Intensity does not correlate well with severity of TR
o R sided CHF: ascites
ECG TVD
- 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
CTX TVD
- R sided cardiomegaly, RAE
- Marked apex shifting to L
2D Echo TVD
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
Doppler echo TVD
TR
Contrast echo TVD
bubbles remain in R heart for prolonged period
o Can see bubbles in hepatic veins
Cardiac KT angio TVD
o Dilated RV
o TR
o Dilated RA
Physiology TVD
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
Natural history TVD
- 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
Ebsteins etiology
- From failure of delamination from ventricular myocardium = adherent
- Rare in dogs, not reported in cats
Gross exam Ebsteins
- 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
Pathiphys ebsteins
- Severe TR, similar to severe TVD
- RV dysfct: abn myocardial structure and fct
o Atrialized RV is thin and dysfunctional - Smaller RV volume
ECG ebsteins
- RBBB frequent
- ↑PR
- Pre-excitation
Cardiac KT dx ebstein
- 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.
Uhl anomaly
- Absence of RVFW myocardial layer
- Apoptosis/ no cell development of myocytes
- Reported in DSH
TVS: gross exam
- Abnormal TV leaflets
o Thickened leaflets
o Commissural fusion
o Short chordae - Annulus may be large
- Hypoplastic/atretic RV
o Unless associated VSD
Pathophys TVS
- ↑ resistance to blood flow from RA → RV
o PG across TV leads to RAE
o R-CHF
