Practical Cardiology Case Studies. Signalment 12 year old SF cocker spaniel

Transcription

1 Practical Cardiology Case Studies Wendy Blount, DVM Nacogdoches TX 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 Exam Dark maroon oral mucous membranes Rear foot pads cyanotic (heart sounds) Split S2 Neurologic exam normal, except dull mental status 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 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 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

2 Arterial blood gases po 2 52 mmhg pco 2 36 mmhg all else normal Pulse oximetry Lip O 2 sat 89% Vulva - O 2 sat 67% 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 ECG S wave mildly deep in leads I,, II, III, avf MEA 90 o Arrhythmia doesn t seem likely Differential Diagnoses Right to left shunt Pulmonary hypertension

3 ECG S wave mildly deep in leads II, III, avf MEA 90 o Arrhythmia doesn t seem likely Differential Diagnoses Right to left shunt Pulmonary hypertension Right to Left Shunt Reverse PDA (right to left) Eisenmeinger s physiology Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram Right to Left Shunt Reverse PDA (right to left) Eisenmeinger s physiology Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram Right to Left Shunt Reverse PDA (right to left) Eisenmeinger s physiology Tetralogy of Fallot AV fistula with pulmonary hypertension Echocardiogram 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 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

4 Reverse PDA 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 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 Reverse PDA 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 Prognosis Can do well short term Poor prognosis long term Survival months to a year or two Phlebotomy interval is progressively shorter Hank Hank Signalment 10 week old male schnauzer Chief Complaint Loud heart murmur heard on examination for routine vaccinations Suspect congenital heart defect Exam mm pink, CRT 2 sec 4/6 ejection murmur loudest at left heart base (audio) Mild superficial pyoderma

5 Hank Hank Initial Differential Diagnoses Pulmonic stenosis Aortic Stenosis Initial Diagnostic Plan Chest x-rays EKG Echocardiogram Hank 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 Hank Hank - Echo EKG Tall P waves ( mv) RA enlargement Deep S waves in leads I, II and III (-13 to -15 mv) RV enlargement Tachycardia bpm Under Buprenex-ace sedation

6 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 RV as thick as LV markedly thickened 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 Plan updated Referral to TAMU for balloon valvuloplasty Atenolol 0.5 mg/kg PO BID (monitor weight to increased dose PRN until cath procedure)

7 Pulmonic Stenosis 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 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 Pulmonic Stenosis 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 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) Signalment 2 year old female chihuahua mix Chief Complaint Loud heart murmur heard on free examination for shelter pup Exam Left apex (audio) 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

8 Thoracic Rads MPA dilation Aortic dilation Generalized cardiomegaly Thoracic Rads LV dilation Elevated trachea Inc VHS LA dilation? Left CHF Perihilar edema Enlarged pulmonary Lobar veins 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 Echocardiogram IVSd 8.0 (n ) 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 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

9 2 week recheck CHF controlled weaned off meds Still doing well 60 days later But. Murmur returned left axillary area (audio) No mitral murmur Surgical ligation Cath procedure for coil placement 2 week Post-Op Rads 2 week Post-Op Rads Asymptomatic for 8 yrs Then began coughing Asymptomatic for 8 yrs Then began coughing FNA Cytology Adenocarcinoma Euthanized 6 months later

10 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 Clinical Features Doppler is required to determine severity Prognosis depends on severity Mild 0-50 mm Hg Moderate mm Hg Severe - >100 mm Hg 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 Echocardiographic Features Doppler can identify those SAS which can not be visualized directly FS usually normal to slightly increased 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 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

11 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 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 ASD and VSD 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 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 ASD and VSD 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 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

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