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Practical Cardiology Case Studies. Wendy Blount, DVM Nacogdoches 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.
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Practical CardiologyCase Studies Wendy Blount, DVM Nacogdoches 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 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 Thoracic radiographs • Normal great vessels • Normal heart size (VHS 9.5) • aortic bulge on VD • No evidence of severe respiratory disease which might cause hypoxia • No evidence of heart failure
Ginger ECG • S wave mildly deep in leads I,, II, III, aVF • MEA 90o • Arrhythmia doesn’t seem likely Differential Diagnoses • Right to left shunt • Pulmonary hypertension
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
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 (video) • 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 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
Reverse PDA Prognosis • Can do well short term • Poor prognosis long term • Survival months to a year or two • Phlebotomy interval is progressively shorter
Gabby 6 month female DSH Presented for OHE PreAnesthetic Exam - HR 100 • No other abnormal findings • Preanesthetic bloodwork normal
Gabby Pre-Anesthetic ECG • Heart rate • P rate is 160 bpm, QRS rate is 100 bpm • Rhythm • no consistent PR interval • P and QRS complexes are disassociated, but each regular 20mm = 1 mV 25 mm/sec 3rd Degree AV block
Gabby • Gabby was not spayed at 6 months of age • When she reached 7 years of age, she had her 4th litter • She was referred to Drs. Miller and Gordon at TAMU for spay • When induced, her heart rate immediately fell to 40 and was progressively dropping • A temporary pacemaker was placed • Gabby was spayed and recovered uneventfully • Gabby turned 17 years old in 2010, and has since passed on
Gabby Dear Doc, Because you took away my favorite pastime, I have turned to a life of substance abuse. It’s your fault. Love, Gabby
3rd degree AV block 3rd Degree AV block is the most common cause of bradycardia in the cat Treatment- cats • Often no treatment needed for cats • AV node pacemaker is 100 per minute • AV node pacemaker is 40-60 per minute in the dog • Cats do well unless they undergo anesthesia • Avoid drugs that increase vagal tone • Alpha blockers – Dexdomitor, Rompun
3rd degree AV block in Dogs • Usually presents for syncope (HR 20-40 per minute) • “Cannon wave” jugular pulses (bradycardia) • Treated with pacemaker implantation • Drug therapy not usually successful • Usually no response to atropine • Atropine often makes 2nd degree block go away • Some have tried theophylline • Prognosis poor without pacemaker • If lactate is high, emergency pacemaker is needed
3rd degree AV block in Dogs Pre-Operative ECG • Atrial rate = 200 per minute • Ventricular rate = 40 per minute 50 mm/sec
3rd degree AV block in Dogs Post-Operative ECG • Ventricular rate = 100 50 mm/sec
Trip Signalment • 2 year old castrated male border collie Chief Complaint/History • Productive Cough, weight loss for 2 months • Breathing hard for a 2 days • Energy good; did well in agility 4 days ago • Owner thinks has had lifelong PU-PD • Has wanted to be in AC this summer – unlike last summer when he enjoyed being outside
Trip Exam • T 102.2, P 168, R 42, CRT 3 sec • BCS 2.5 • BP 100 • Bounding pulses, notable in dorsal pedal artery • Precordial – exaggerated left apical heave • Lung sounds clear
Trip Exam • 3 murmurs: • PMI left base • To-and-fro murmur 3/6 • aortic stenosis in systole, regurg in diastole 2. PMI left apex, but heard all over chest • Holosystolic murmur 3/6 • Mitral regurgitation due to LHF 3. PMI Carotid artery • 2/6 ejection murmur • aortic stenosis
Trip Differential Diagnoses • Aortic endocarditis • SAS with aortic regurgitation • Mitral regurgitation (endocarditis?) Diagnostic Plan • Thoracic radiographs • EKG • Echocardiography
Trip EKG • Normal sinus rhythm for 10 minutes
Trip EKG • Normal sinus rhythm for 10 minutes
Trip EKG • Normal sinus rhythm for 10 minutes Thoracic Radiographs • Interstitial pattern caudal lung fields • Vertebral heart score 10.5 • Enlarged cranial pulmonary lobar vein • Mildly enlarged left atrium • Early left congestive heart failure
Trip - Echo Short Axis – LV Apex • No abnormalities noted Short Axis – LV PM
Trip - Echo Short Axis – LV Apex • No abnormalities noted Short Axis – LV PM
Trip - Echo Short Axis – LV Apex • No abnormalities noted Short Axis – LV PM • LVIDD – 57.3 (n 31.3-34) • IVSTS – 15.5 mm (n 12.6-13.7) • LVIDS – 41.1 mm (18.8-20.7) • FS = (57.3-41.1)/57.3 = 28% (n 30-46%) • EF = 54% (n >70%)
Trip - Echo Short Axis – MV • EPSS – 8 mm (n 0-6) Short Axis – Ao/RVOT • AoS – 20.2 (normal) • LAD – 27.8 (n 19.0-20.5) • LA/Ao – 27.8/20.2 = 1.38 (n 0.8-1.3) • Aortic valve leaflets are hyperechoic
Trip - Echo Short Axis – MV • EPSS – 8 mm (n 0-6) Short Axis – Ao/RVOT • AoS – 20.2 (normal) • LAD – 27.8 (n 19.0-20.5) • LA/Ao – 27.8/20.2 = 1.38 (n 0.8-1.3) • Aortic valve leaflets are hyperechoic
Trip - Echo Short Axis – MV • EPSS – 8 mm (n 0-6) Short Axis – Ao/RVOT • AoS – 20.2 (normal) • LAD – 27.8 (n 19.0-20.5) • LA/Ao – 27.8/20.2 = 1.38 (n 0.8-1.3) • Aortic valve leaflets are hyperechoic
Trip - Echo Short Axis – PA • No abnormalities noted Long Axis – 4 Chamber
Trip - Echo Short Axis – PA • No abnormalities noted Long Axis – 4 Chamber
Trip - Echo Short Axis – PA • No abnormalities noted Long Axis – 4 Chamber • LA appeared mildly enlarged • IVS bowed anteriorly toward RV • No evidence of mitral encodarditis or endocardiosis • Vegetation on aortic valve
Trip - Echo Long Axis – LVOT (video) • Hyperechoic thickened mitral valve leaflets Diagnosis • Aortic endocarditis Therapeutic Plan • Elected euthanasia due to poor prognosis
Valvular Endocarditis Clinical Features • Present for FUO, weight loss or heart failure • Aortic much more common than mitral • Dogs much more common than cats • Many bacteria including Bartonella • Breed predisposition • Rottweiler, Boxer, Golden retriever • Newfoundland, German shepard