Practical Cardiology Case Studies

Practical CardiologyCase Studies

Wendy Blount, DVMNacogdoches TX

Jasper

Signalment:• Middle Aged Adult Norwegian Forest Cat• Male Castrated• 13 pounds

Chief Complaint:• Acute Dyspnea 1 day after sedation with ketamine

and Rompun for grooming• Cannot auscult heart or lung sounds well - muffled

Jasper

Immediate Diagnostic Plan:• Lasix 25 mg IM – then in oxygen cage• When RR <50, lateral thoracic radiograph

Differential Diagnosis – Pleural effusion• Transudate - Hypoalbuminemia• Modified Transudate – Neoplasia, CHF• Exudate – Blood, Pyothorax, FIP• Chylothorax (chart)

Jasper

Initial Therapeutic Plan:• Thoracocentesis• Tapped both right and left thorax• Removed 400 ml of pink opaque fluid that

resembled pepto bismol• Fluid had no “chunks” in itDifferential Diagnosis – updated• Pyothorax• Chylothorax

Jasper

Initial Diagnostic Plan:• Fluid analysis

– Total solids 5.1– SG 1.033– Color- pink before spun, white after– Clarity – opaque– Nucelated cells 8500/ml– RBC 130,000/ml– HCT 0.7%

Jasper

Initial Diagnostic Plan:• Fluid analysis

– Lymphocytes 5600/ml– Monocytes 600/ml– Granulocytes 2300/ml– No bacteria seen– Triglycerides 1596 mg/dl– Cholesterol 59 mg/dl

Chylothorax

Jasper

DDx Chylothorax• Trauma – was chewed by a dog 2-3 mos ago• Right Heart Failure• Pericardial Disease• Heartworm Disease• Neoplasia

– Lymphoma– Thymoma

• Idiopathic

Jasper

Diagnostic Plan - Updated• PE & Cardiovascular exam• CBC, general health profile, electrolytes• Occult heartworm test• Post-tap chest x-rays• Echocardiogram

Jasper

Exam• Temp 100, P 180, R 48, BCS 3, BP 115• 3/6 systolic murmur• Anterior mediastinum compressible• Pleural rubs• No jugular pulses, no hepatojugular reflux• Peripheral pulses slightly weak• Mucous membranes pink, CRT 3 sec

Jasper

Bloodwork• Occult Heartworm Test - negative• CBC – normal• GHP –

– Glucose 134 (n 70-125)– Cholesterol 193 & TG 137 (both normal)

Chest X-rays• Post-tap chest x-rays

Jasper

Chest X-rays• Minimal pleural effusion• No cranial mediastinal masses• Normal cardiac silhouette (VHS 7.5)• Normal pulmonary vasculature• Lungs remain scalloped

Jasper – Echo

Short Axis – LV apex (video of similar cat)• No abnormalities notedShort Axis – LV PM• No abnormalities noted• IVSTD – 8.8 mm (n 3-6)• LVIDD – 16.2 mm (normal)• LVPWD – 7.2 mm (n 3-6)• IVSTS – 9.8 mm (n 4-9)• LVIDS – 10.5 mm (normal)• LVPWS – 10.1 mm (n 4-10)• FS – 35%

Jasper – Echo

Short Axis – MV• No abnormalities noted

Short Axis – Ao/RVOT• Smoke in the LA• AoS – 11.7 mm ( normal)• LAD – 10.5 (normal)• LA/Ao – 0.9 (normal)

Jasper – Echo

Short Axis – PA• Difficult to evaluate due to “rib shadows”Long Axis – 4 Chamber• Hyperechoic “thingy” in the LA, with smokeLong Axis – LVOT• Aortic valve seems hyperechoic, but not

nodular• 2-3 cm thrombus free in the LA

Jasper – Echo

Short Axis – Ao/RVOT - repeated• LA 2-3x normal size, with Smoke• AoS – 11.7 mm ( normal)• LAD – 29 mm (n 7-17)• LA/Ao – 2.5 (n 0.8-1.3)

Jasper – Echo

Therapeutic Plan - Updated• Furosemide 12.5 mg PO BID• Enalapril 2.5 mg PO BID• Rutin 250 mg PO BID• Low fat diet• Plavix 18.75 mg PO SID• Lovenox 1 mg/kg BID• Fragmin 1 mg/kg BID• Clot busters only send the clot sailing

Jasper – Echo

Recheck – 1 week• Jasper doing exceptionally well –back to

normal.• Lateral chest radiograph• Jasper declined all other diagnostics, without

deep sedation/anesthesia• Will do BUN, Electrolytes, BP, recheck echo to

assess thrombus in one month

Jasper – Echo

Recheck – 1 month• Jasper doing exceptionally well • Lateral chest radiograph – no change• Jasper declined all other diagnostics, without

deep sedation/anesthesia• Will do BUN, Electrolytes, BP, recheck echo to

assess thrombus at 6 month check-up.

Jasper – Echo

Recheck – 6 months• Jasper doing exceptionally well • BP – 140, chext x-rays no change• Jasper declined all other diagnostics, without

deep sedation/anesthesia• May never do BUN, Electrolytes, recheck echoLong Term Follow-up• Jasper still doing well 18 months later• On lasix & enalapril only

Hypertrophic Cardiomyopathy

Clinical Characteristics• Diastolic dysfunction – heart does not fill well• Poor cardiac perfusion• Most severe disease in young to middle aged

male catss• Can present as

– Murmur on physical exam– Heart failure (often advanced at first sign)– Acute death– Saddle thrombus


Radiographic Findings• + LV enlargement

– Elevated trachea, increased VHS• LA + RA enlargement seen on VD in cats• + LHF

– Pleural effusion– Pulmonary edema– Lobar veins >> ateries


Echocardiographic Abnormalities• LV and/or IVS thicker than 6 mm in diastole• Symmetrical or asymmetrical• Can be only a thick IVS• Can be primarily very thick papillary muscles• LVIDD usually normal to slightly reduced• FS normal to increased, unless myocardial

failure developing• LVIDS sometimes 0 mm


Echocardiographic Abnormalities• LA often enlarged• RA sometimes also enlarged• “Smoke” can be seen in the LA• Rarely a thrombus in the LA• Transesophageal US more sensitive at

detecting LA thrombi• Borderline thickened LV should not be

diagnosed as HCM without LA enlargement


DDx LV thickening• Hypertension• Hyperthyroidism• (Chronic renal failure)• Only HCM causes severe thickening of LV

Dogs can rarely have HCM• Cocker spaniels


Treatment • Manage heart failure

– Therapeutic thoracocentesis in a crisis– Diuretics– ACE inhibitors

• Beta blockers – if persistent tachycardia• Calcium channel blockers – if thickening

significant• Treat hypertension if present


Treatment • Q6month rechecks

– Chest x-rays– CBC, GHP, electrolytes, blood gases– ECG if arrhythmia ausculted or syncope– BP

• Sooner if RR >40 at rest• Sooner if any open mouth breathing ever


Prognosis • Q6month rechecks

– Chest x-rays– CBC, GHP, electrolytes, blood gases– ECG if arrhythmia ausculted or syncope– BP

• Sooner if RR >40 at rest• Sooner if any open mouth breathing ever


Screening• Genetic test is available at Washington State U

– http://www.vetmed.wsu.edu/deptsvcgl/

• Auscultation not always sensitive• Echocardiogram can detect early in breeds

predisposed• No evidence that early intervention changes

outcome

http://www.vetmed.wsu.edu/deptsvcgl/




HOCM with SAM• Hypertrophic Obstructive Cardiomyopathy• Systolic Anterior Motion• The septal leaflet of the mitral valve is sucked

into the LVOT instead of moving back toward the atria during systole

• If it happens intermittently, it can cause an intermittent murmur

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• Split S2• Neurologic exam normal, except dull mental

statusDifferential Diagnosis - cyanosis• Respiratory hypoxia• Cardiac hypoxia

Ginger

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

Ginger

Arterial blood gases• pO2 – 55 mmHg

• pCO2 – 38 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

Right to Left Shunt• Reverse PDA

– Eisenmeinger’s physiology• Tetralogy of Fallot• AV fistula with pulmonary hypertensionEchocardiogram• 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• 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• False negatives when bubbles disperse quickly

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• 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 DSHPresented for OHE

Exam - HR 100• No other abnormal

findings

Gabby

ECG• Heart rate – 100 per minute – QRS complexes

– 170 per minute – P waves• Rhythm – no consistent PR interval

– P and QRS complexes are disassociated, but each regular• All other measurements normal• 3rd degree AV block

3rd degree AV block

Treatment- cats• Avoid drugs that increase vagal tone

– Alpha blockers – Domitor, Rompun• Often no treatment needed for cats

– AV node pacemaker is 100 per minute– AV node pacemaker is 40-60 per minuted in the dog

• Surgery can be supported with temporary pacemaker in cats

3rd degree AV block

Treatment and Prognosis - Dogs• Usually presents for syncope• “Cannon wave” jugular pulses• 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

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Practical Cardiology Case Studies