Practical Cardiology Congenital Heart Defects Wendy Blount, DVM Nacogdoches TX

Jon Carlson – Tyler TX

Ginger Signalment 12 year old SF cocker spaniel Chief complaint Several episodes of collapse during the past month Description matches partial seizure Rear legs get weak on walks Lethargic and dull in general

Ginger Exam Dark maroon oral mucous membranes Rear foot pads cyanotic (heart sounds) Split S2 Neurologic exam normal, except dull mental status

Ginger Differential Diagnosis – Split S2 Pulmonic and aortic valves don’t close at the same time Pulmonary hypertension Normal variation in giant dogs Reverse PDA Differential Diagnosis - cyanosis Respiratory hypoxia Cardiac hypoxia

Ginger Initial Diagnostic Plan CBC, GHP, electrolytes Arterial blood gases, Pulse oximetry ECG Thoracic radiographs, VetBLUE Bloodwork Tech couldn’t get enough serum for serology CBC – PCV 73% GHP and electrolytes - normal

Ginger DDx Differential Cyanosis FATE – Femoral Artery ThromboEmbolism Lack of femoral pulses Feet cool to the touch Right to Left shunt – ductus is distal to the brachiocephalic trunk Reverse PDA AV fistula with pulmonary hypertension Tetralogy of Fallot

Ginger Arterial blood gases pO2 – 52 mmHg pCO2 – 36 mmHg all else normal Pulse oximetry Lip – O2 sat 89% Vulva - O2 sat 67%

Ginger

Ginger

Ginger Thoracic radiographs Normal great vessels Normal heart size (VHS 9.5) aortic bulge on VD, PA bulge on VD No evidence of severe respiratory disease which might cause hypoxia No evidence of heart failure

Ginger Right to Left Shunt Reverse PDA (right to left) Eisenmeinger’s physiology Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram

Ginger Right to Left Shunt Reverse PDA (right to left) Eisenmeinger’s physiology Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram

Ginger Right to Left Shunt Reverse PDA (right to left) Eisenmeinger’s physiology Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram

Ginger Right to Left Shunt Reverse PDA (right to left) Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram RV thickening RV normally thinner than LV No PDA seen without Doppler

Ginger Bubble Study Place venous catheter Shake 5-10 cc saline vigorously Place US probe where you can look for shunting Long 4 chamber view Abdominal aorta Inject IV quickly Bubbles normally appear on the right Watch for bubbles on the left (this means R to L shunt) False negatives when bubbles disperse quickly

Ginger Bubble Study Place venous catheter Shake 5-10 cc saline vigorously Place US probe where you can look for shunting Long 4 chamber view Abdominal aorta Inject IV quickly Bubbles normally appear on the right Watch for bubbles on the left (this means R to L shunt) False negatives when bubbles disperse quickly

Reverse PDA Reverse PDAs are usually large, providing no resistance to blood flow Ductus is often as large in diameter as the great vessels it connects increase in pulmonary artery pressure combined with the increase in pulmonary blood flow creates pathologic responses in the pulmonary arteries over time a continuous murmur is heard during the first days to weeks of life but disappears before the eighth week Often do well until polycythemia develops late in life

Reverse PDA Treatment Ligation of right to left shunting PDA results in death due to pulmonary hypertension Has been ligated in stages without causing death Cyanosis and symptoms usually persist Managed Medically by periodic phlebotomy Remove 10 ml/lb and replace with IV fluids Eliminate hyperviscosity without inducing hypoxia Goal for PCV is 60-65% Excellent blood for RBC transfusion ;-) Repeat when clinical signs return

Reverse PDA Prognosis Can do well short term Poor prognosis long term Survival months to a year or two Phlebotomy interval is progressively shorter, and then eventually the phlebotomies become minimally effective to ineffective

Shawn Penn – Lufkin TX

Shawn Penn – Lufkin TX

Hank Signalment 10 week old male schnauzer Chief Complaint Loud heart murmur heard on examination for routine vaccinations Suspect congenital heart defect

Hank Exam mm pink, CRT 2 sec 4/6 ejection murmur loudest at left heart base (audio) Mild superficial pyoderma

Hank Initial Differential Diagnoses Pulmonic stenosis Aortic Stenosis Initial Diagnostic Plan Chest x-rays,VetBLUE EKG Echocardiogram

Hank

Hank

Hank

Hank VetBlue – dry lungs Thoracic radiographs Dorsally elevated trachea Vertebral heart score 9.5 Right heart enlargement Right auricular/atrial enlargement Distended caudal vena cava Bulge at main pulmonary artery

Hank - Echo

Hank - Echo Short Axis – LV Apex RV seems thickened Short Axis – LV PM, MV, Ao/RVOT RV as thick as LV – markedly thickened IVS is flattened

Hank - Echo

Hank - Echo Short Axis – PA MPA dilated RV as thick as LV – markedly thickened Long Axis – 4 Chamber Aberrant septum dividing RA into 2 chambers – cranial and caudal Long Axis – LVOT

Hank - Echo

Hank - Echo Diagnosis Likely Pulmonic Stenosis DDx RV thickening Heartworms impossible in a 10 week old puppy Pulmonary hypertension rare in a 10 week old puppy Need Doppler to confirm, and to determine gradient Cor triatriatum dexter

Hank - Echo Plan – updated Referral to TAMU for balloon valvuloplasty Atenolol 0.5 mg/kg PO BID (monitor weight to increased dose PRN until cath procedure)

Pulmonic Stenosis Echocardiographic abnormalities RV thickening Post-stenotic dilatation of MPA Pulmonic valve may be thickened with poor movement Paradoxical septal motion may be noted in severe cases Tricuspid dysplasia is a common concurrent malformation RHF is rare in dogs with PS alone Many PS dogs that develop RHF also have tricuspid dysplasia (Client Handout)

Suzie Signalment 2 year old female chihuahua mix Chief Complaint Loud heart murmur heard on free examination for shelter pup

Suzie Exam Left apex (audio) Left axilla (audio) Hyperkinetic pulses holosystolic murmur PMI left apex (MR murmur) due to left volume overload Left axilla (audio) Continuous machinery murmur at the left base (left armpit) Hyperkinetic pulses Left apical heave on precordial palpation

Suzie Thoracic Rads MPA dilation Aortic dilation Generalized cardiomegaly

Suzie Thoracic Rads LV dilation LA dilation ? Left CHF Elevated trachea Inc VHS LA dilation ? Left CHF Perihilar edema Enlarged pulmonary Lobar veins

Suzie Treatment Furosemide 12.5 mg PO BID Enalapril 2.5 mg PO BID Pimobendan 1.25 mg PO BID 2 week recheck CHF controlled – resolution of edema

Suzie Echocardiogram LA:Ao – 1.3 (n. 0.8-1.3) IVSd 8.0 (n. 6.2-7.8) LVIDd 35.1 (n. 21.3-25.8) LVWd 7 (n. 5.0-6.3) IVSs 11.0 (n. 9.4-11.2) LVIDs 15.1 (n. 11.9-15.2) IVDs 9.3 (n. 8.3-10.0) LAd 18 (n. 13.4-16.1) AoS 14.1 (n. 13.5-15.5) LA:Ao – 1.3 (n. 0.8-1.3) FS = 57% MPA jet dilation Can see PDA at transverse MPA view Eccentric hypertrophy LV overload, CHF controlled No Myocardial failure Dx - PDA

Suzie

Patent Ductus Arteriosus Echocardiographic Features Can see PDA at transverse MPA view Doppler can find PDAs that aren’t easily visualized FS hyperdynamic unless myocardial failure

Suzie Treatment Surgical ligation

Suzie 2 week recheck CHF controlled – weaned off meds Still doing well 60 days later But…. Murmur returned – left axillary area (audio) No mitral murmur Treatment Cath procedure for coil placement

Suzie 2 week Post-Op Rads

Suzie 2 week Post-Op Rads

Suzie Asymptomatic for 8 yrs Then began coughing

Suzie Asymptomatic for 8 yrs Then began coughing FNA Cytology Adenocarcinoma Euthanized 6 months later

Sub-Aortic Stenosis Clinical Features Doppler is required to determine severity Prognosis depends on severity Mild – 0-50 mm Hg Moderate – 50-100 mm Hg Severe - >100 mm Hg

Sub-Aortic Stenosis

Sub-Aortic Stenosis Echocardiographic Features IVS and LVPW thickening An echodense ridge or band may be seen on the long LVOT view, especially if severe Aortic valve may be abnormal Thickened (rare) Decreased movement (rare) Delay in opening of AV after systole Excessive systolic fluttering

Sub-Aortic Stenosis Echocardiographic Features Doppler can identify those SAS which can not be visualized directly FS usually normal to slightly increased

Sub-Aortic Stenosis Treatment Treat arrhythmia if present Atenolol 0.5 mg/kg PO BID Treat left heart failure if present Treat aortic regurgitation if present Hydralazine 0.5 mg/kg PO BID Titrate up to 2 mg/kg PO BID to reduce systolic BP by 10-20 mm Hg

Sub-Aortic Stenosis Treatment Treat arrhythmia if present Atenolol 0.5 mg/kg PO BID Treat left heart failure if present Treat aortic regurgitation if present Hydralazine 0.5 mg/kg PO BID Titrate up to 2 mg/kg PO BID to reduce systolic BP by 10-20 mm Hg

Sub-Aortic Stenosis Treatment Treat arrhythmia if present Atenolol 0.5 mg/kg PO BID Treat left heart failure if present Treat aortic regurgitation if present Hydralazine 0.5 mg/kg PO BID Titrate up to 2 mg/kg PO BID to reduce systolic BP by 10-20 mm Hg

Sub-Aortic Stenosis Treatment Treat arrhythmia if present Atenolol 0.5 mg/kg PO BID Treat left heart failure if present Treat aortic regurgitation if present Hydralazine 0.5 mg/kg PO BID Titrate up to 2 mg/kg PO BID to reduce systolic BP by 10-20 mm Hg

ASD and VSD Echocardiographic Features - VSD In dogs and cats, most VSDs occur in membranous IVS, at the top of the LV near the atria Need to be 1 cm to reliably seen on echo Doppler can find those that can not be seen directly May see abnormal septal motion due to conduction interruption Occasionally can see right cusp of AV prolapsing, creating aortic regurgitation Huge RA and MPA; RV dilation

ASD and VSD Echocardiographic Features - ASD ASD much less likely to cause clinical signs than VSD Do not confuse with drop-out of fossa ovalis Doppler can confirm If large enough, may see right volume overload Enlarged RA and RV Enlarged MPA

Summary PowerPoint – Cases – Congenital Heart Defects .pdf of PowerPoint – Cases - Congenital Heart Defects Client Handouts PDA Subaortic Stenosis Pulmonic Stenosis VSD