1. Practical Cardiology Case Studies
Wendy Blount, DVM
Nacogdoches TX

2. 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

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

4. 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

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

6. 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

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

8. Ginger

9. Ginger

10. 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

11. Ginger
ECG

12. Ginger ECG S wave mildly deep in leads II, III, aVF MEA 90o
Arrhythmia doesn’t seem likely
Differential Diagnoses
Right to left shunt
Pulmonary hypertension
Severe respiratory disease and anemia ruled out

13. Ginger

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

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

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

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

18. 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 (video)
Watch for bubbles on the left (this means R to L shunt)
False negatives when bubbles disperse quickly

19. 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

20. 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

21. Reverse PDA Treatment Hydroxyurea
30 mg/kg/day for 7 to 10 days followed by 15 mg/kg/day.
CBC q1-2 weeks
D/C when Bone marrow suppression
Resume lower dose
Some dogs require higher doses
side effects – GI and sloughing of the nails

22. 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

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

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

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

26. Hank

27. Hank

28. Hank 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

29. Hank EKG Tall P waves (0.5-0.6 mV) RA enlargement
Deep S waves in leads I, II and III (-13 to -15 mV)
RV enlargement
Tachycardia bpm
Under Buprenex-ace sedation

30. Hank - Echo

31. 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

32. Hank - Echo

33. 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

34. Hank - Echo

35. 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

36. 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)

37. Pulmonic Stenosis Clinical features Many breed predispositions
Bulldog, chihuahua, Beagle, Cavalier
Often valvular and subvalvular
Valvular defect can be corrected by valvuloplasty
Prognosis varies, depending on severity
Mild – less than 50 mm Hg gradient
Moderate – mm Hg
Severe - >100 mm Hg
Can be progressive

38. Pulmonic Stenosis Clinical features
Bulldogs and Boxers can have left coronary artery anomaly, which can preclude balloon valvuloplasty
Arrhythmia is much more common than RHF
May be part of Tetralogy of Fallot PS
RV hypertrophy
VSD
Overriding aorta

39. Pulmonic Stenosis Coronary Artery Anomaly
Instead of R and L coronary aa, there is a single coronary a.
It splits and the left branch encircles the pulmonary a.
It can be ruptured if the PS is ballooned
These dogs may have normal PV and functional PS due to this anomaly

40. 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)

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

42. 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

43. Suzie Thoracic Rads MPA dilation Aortic dilation
Generalized cardiomegaly

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

45. 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

46. Suzie Echocardiogram LA:Ao – 1.3 (n. 0.8-1.3) IVSd 8.0 (n. 6.2-7.8)
LVIDd 35.1 (n )
LVWd 7 (n )
IVSs 11.0 (n )
LVIDs 15.1 (n )
IVDs 9.3 (n )
LAd 18 (n )
AoS 14.1 (n )
LA:Ao – 1.3 (n )
FS = 57%
MPA jet dilation
Can see PDA at transverse MPA view
Eccentric hypertrophy
LV overload, CHF controlled
No Myocardial failure
Dx - PDA

47. Suzie

48. 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

49. Suzie
Treatment
Surgical ligation

50. 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

51. Suzie
2 week Post-Op Rads

52. Suzie
2 week Post-Op Rads

53. Suzie
Asymptomatic for 8 yrs
Then began coughing

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

55. Sub-Aortic Stenosis Clinical Features
Large breeds more common than small
Valvular and supravalvular stenosis very rare
Does not lend itself to balloon valvuloplasty
Patch grafts are being tried at TAMU
Anatomic expression may not occur until several weeks to months old
Disease can be progressive or regressive

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

57. Sub-Aortic Stenosis Echocardiographic Features
LV (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

58. Sub-Aortic Stenosis Echocardiographic Features
Doppler can identify those SAS which can not be visualized directly
FS usually normal to slightly increased
(Video 1) Shiloh-Lion
(Video 2) Shiloh-Lion

59. 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 mm Hg

60. 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 mm Hg

61. 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 mm Hg

62. 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 mm Hg

63. 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 mm Hg

64. ASD and VSD Clinical Features
Disease is a result of left to right shunting
This causes pulmonary hypertension and right heart failure
caudal caval distension, hepatic vein distension
jugular vein distension/pulses/reflux
Ascites
Pericardial effusion
Pleural effusion

65. 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

66. 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

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