Practical Cardiology Case Studies

Practical CardiologyCase Studies

Wendy Blount, DVMNacogdoches TX

Daisy

Signalment• 15 year old spayed female mixed terrier• 11 pounds

Chief Complaint• Became dyspneic while on vacation, as they

drove over a mountain pass• Come to think of it, she has been breathing

hard at night for some time

Daisy

Exam• T 100.2, P 185, R – 66, BP – 145, BCS – 3.5• Increased respiratory effort (heart sounds)• 3/6 holosystolic murmur loudest at left apex• Mucous membranes pale pink• Crackles in the small airways• Pulses weak, somewhat irregular, no pulse

deficits• CRT 3.5-4 seconds

Daisy

Differential Diagnosis - Dyspnea• Suspect congestive heart failure• Suspect mitral regurgitation• Concurrent respiratory disease can’t be ruled out

Initial Diagnostic Plan• Chest x-rays, ECG• CBC, mini-panel, electrolytes

Daisy

CBC, mini-panel, electrolytes• Normal

Daisy


Daisy


Daisy

CBC, mini-panel, electrolytes• NormalThoracic radiographs• Markedly enlarged LA• Compressed left mainstem bronchus• Perihilar edema• Vertebral heart score 11.75• Elevated trachea – LV enlargement• Right heart enlargement, enlarged pulmonary lobar aa.• Mildly enlarged liver• Enlarged caudal vena cava

Daisy

ECG

Daisy

Calculating Instantaneous Heart Rate (iHR)• Measure R wave to R wave (9mm)•

• Divide by paper speed (25 mm/sec) for time per beat9mm x _sec_ = 0.36 sec per heart beat

25mm•

• Calculate beats per minute_heart beat_ x _60 sec = 166 beats/minute

0.36 sec minute

Daisy

ECG• Rate – 110 bpm• Rhythm – sinus arrhythmia with VPCs• MEA – normal (lead II has tallest R waves)• P, QRS and T waves – normal

– No evidence of enlarged LA and LV on the ECG• VPC – abnormal QRS

– Comes too early (166 bpm)– Wide and bizarre shape– Not preceded by a P wave– T wave opposite in polarity than normal QRS

Daisy

Initial Therapeutic Plan• Lasix 25 mg IM, then 12.5 mg PO BID• Enalapril 2.5 mg PO BID• Owner is a lab tech, and set up oxygen mask to

use PRN at home• Recheck BUN, potassium, chest rads 3-5 days• Come back sooner if respiratory rate at rest is

above 40 per minute without oxygen

Daisy

When to treat VPCs• VPCs unusual for MR• Did not treat in this case, because:

– MR dogs not predisposed to sudden death• SAS and DCM are most common causes of sudden death

due to arrhythmia– Ectopic focus not firing at a fast rate (166 bpm)

• <200 bpm iHR is well away from the T wave– No pulse deficits – did not affect hemodynamics– Primary treatments for VPC are Sotalol or B blocker

• Negative inotropes not ideal for myocardial failure

Daisy

Recheck – 4 days• Daisy’s breathing is much improved (30-40 at

rest)• Lateral chest x-ray• Electrolytes normal • BUN 52

Daisy

Recheck – 4 days• Daisy’s breathing is much improved (30-40 at

rest)• Lateral chest x-ray• Electrolytes normal • BUN 52

Daisy

Diagnostic Plan - updated• Decrease enalapril to SID• Recheck BUN 1 week• Recheck chest rads 1 week

Recheck – 1 week• BUN – 37• Thoracic rads no change• Request recheck in 3 months, or sooner if respiratory

rate at rest is above 40 per minute

Daisy

2 months later• Daisy is breathing hard again at night

Exam• Same as initial presentation

Diagnostic Plan• CBC, mini-panel, electrolytes• Chest x-rays

Daisy




Daisy




Daisy

Bloodwork• CBC, electrolytes normal• BUN 88

Therapeutic Plan• Increase furosemide to 18.75 mg PO BID• Add hydralazine 2.5 mg PO BID• Recheck chest rads, BUN, electrolytes, blood

pressure 1 week

Daisy

Recheck – 1 week• Clinically much improved – respiratory rate 30-

40 per minute at rest• electrolytes normal• BUN 58• Blood pressure 135• Chest x-rays• Recommend recheck in 3 months, or sooner if

respiratory rate above 40 per minute at rest

Daisy

Recheck – 1 week• Clinically much improved – respiratory rate 30-

40 per minute at rest• electrolytes normal• BUN 58• Blood pressure 135• Chest x-rays• Recommend recheck in 3 months, or sooner if

respiratory rate above 40 per minute at rest

Daisy

Recheck – 6 months• Daisy dyspneic again

Exam• Similar to last crisis – BP 90

Diagnostic Plan• CBC, mini-panel, electrolytes• Echocardiogram, ECG, chest x-rays

Daisy

Bloodwork• CBC, electrolytes normal• BUN 105, creat 2.1

Chest x-rays

Daisy


Chest x-rays

Daisy


Chest x-rays• Similar to last crisis

ECG• Sinus tachycardia, wide P wave

Daisy - Echo

Short Axis – LV apex (video)• LV looks big

Short Axis – LV papillary muscles• IVSTD – 6.0 mm – low normal• LVIDD – 35 mm (n 20.2-25)• LVPWD – 4.3 mm – low normal• IVSTS – 9.4 mm – normal• LVIDS – 25 mm (n 11.1-14.6)• LVPWS – 8.4 mm - normal

Daisy - Echo

Short Axis – LV papillary muscles• IVSTD – 6.0 mm – low normal• LVIDD – 35 mm (n 20.2-25)• LVPWD – 4.3 mm – low normal• IVSTS – 9.4 mm – normal• LVIDS – 25 mm (n 11.1-14.6)• LVPWS – 8.4 mm – normal

• FS – (35-25)/35 = 29% (normal 30-46%)

Daisy - Echo

Short Axis - MV• MV leaflets hyperechoic and thickened• EPSS – 8 mm (n 0-6)

Short Axis – Aortic Valve/RVOT• LA appears 2-3x normal size• AoS – 13.0 – normal• LAD – 33 mm (n 12.8-15.6)• LA/Ao = 2.5 (n 0.8-1.3)

Daisy - Echo

Long View – 4 Chamber• LV and LA both appear large• MV is very thick and knobby, with some

prolapse into the LA

Daisy - Echo


prolapse into the LA

Daisy - Echo


prolapse into the LA• Pulmonary vein markedly enlarged

Long View – LVOT• Large LA, Large LV (video)

Daisy

Therapeutic Plan• Increase hydralazine to 5 mg PO BID• Add spironolactone 12.5 mg PO BID• Add pimobendan 1.25 mg PO BID• Increase furosemide to 18.75 mg PO TID x 2

days, then decrease to BID if respiratory rate decreases to less than 40 per minute at rest.

• Recheck 1 week – BUN, creat, phos, electrolytes, chest rads, BP

Daisy

Recheck – 1 week• Clinically improved again• BP - 125• BUN 132, creat 2.6, phos 6.6• Electrolytes normal• chest rads improved pulmonary edema

Therapeutic Plan – Update• Add aluminum hydroxide gel 2 cc PO BID

Daisy

5 Months later • Coughing getting worse• Chest rad show no pulmonary edema• LA getting larger

Therapeutic Plan – Update• Add torbutrol 2.5 mg PO PRN to control cough

Daisy

18 Months after initial presentation• Owner discontinue pimobendan due to GI upset

28 months after initial presentation• Daisy finally took her final breath• BUN >100 for 22 months

Chronic MV Disease

• May be accompanied by similar TV disease (80%)• TV disease without MV disease possible but rare• LHF and/or RHF can result• Right heart enlargement can develop due to

pulmonary hypertension, in turn due to LHF• Myocardial failure and CHF are not directly

related

Chronic MV Disease

Thoracic radiograph abnormalities:• LV enlargement

– Elevated trachea– increased VHS

• LA enlargement – often largest chamber– Compressed left bronchus

• + left heart failure– Pulmonary edema– Lobar veins larger than arteries

Chronic MV Disease

Echo abnormalities: (doppler echo)• LA and/or RA dilation, LV and/or RV dilation• Exaggerated IVS motion (toward RV in diastole)• Increased FS first, then later decreased FS• Thickened valve leaflets• If TV only affected, left heart can appear compressed,

small and perhaps artifactually thick• Ruptured CT –

– MV flips around in diastole– MV flies up into LA during systole – “MV flail” (video)– May see trailing CT, or CT floating in the LV

Chronic MV Disease

ECG abnormalities:• Wide or notched P wave

– Enlarged LA• Tall R wave

– Enlarged LV• Right Bundle Branch block

– Wide QRS– Deep S wave

• Left Bundle Branch Block– Wide QRS– Tall R wave

Chronic MV Disease

Right Heart Failure• Medications similar to LHF• Medications not as effective at eliminating fluid

congestion– More effective at preventing fluid accumulation, once controlled

• Periodic abdominocentesis and/or pleurocentesis required

• Prognosis for RHF and LHF is extremely variable

Chronic MV Disease

Classification of Chronic AV Valve Disease• Class I - small, discrete nodules along the edge of the

valve leaflets• Class II - free edges are thickened and the edges of

the leaflets become irregular. Some CT are thickened.• Class III - valve edges grossly thickened and nodular,

extending to the base of the valve leaflets. There is redundant tissue, resulting in prolapse into the LA. CT are thickened and may rupture, resulting in mitral valve flail. CT to the septal leaflet can also elongate.

Chronic MV Disease

LA Jet Lesions• fibrous plaques in the endocardium in a region

subjected to the impact of the high velocity MR jet. • Endomyocardial splits or tears may also be identified. • On occasion, a full thickness left atrial tear occurs

resulting in hemopericardium, pericardial tamponade, and usually death.

• Rarely, a full thickness endomyocardial tear will involve the interatrial septum, causing an acquired atrial septal defect.

(MR Client Handout)

MVD in Cavaliers

• Leading cause of death in Cavaliers• CHF can develop as young as 1-3 years old• First sign of disease is mitral murmur

– Careful annual auscultation• Radiographs should be done as soon as murmur is

detected– q6months when progressing– annually for stable disease– Sooner when respiratory rate exceeds 40 per minute

• Doppler Echo when abnormalities are present on rads

MVD in Cavaliers

• The median survival period from grade III CHF due to MVD is approximately seven months, with 75% of the dogs dead by one year

• Current recommendation is that no Cavalier be bred until after 5 years of age, with no murmur

• At this time, a majority of Cavaliers are affected• Many progress to grade II CHF

(Client Handout)

Signalment• 12 year old spayed miniature schnauzerChief Complaint• Episodes of ConfusionExam• G3 dental tartar• Alternating periods of normal heart rate,

tachycardia and bradycardia• Pulse deficits during tachycardia

Susie

Work-up• CBC, panel, electrolytes, UA normal• Chest x-rays

Susie

Work-up• CBC, panel, electrolytes, UA normal• Chest x-rays

Susie

Vertebral Heart Size

= 10.7(normal 8.5-10.5)Enlarged

main pulmonary

artery

Work-up• CBC, panel, electrolytes, UA normal• Chest x-rays• Susie is not on heartworm prevention

Susie

Work-up• CBC, panel, electrolytes, UA normal• Chest x-rays• Susie is not on heartworm prevention

Susie

ECG• Heart Rate

– Very erratic an impossible to estimate– >200 bpm for periods of up to 2-4 seconds– Some periods of normal heart rate– Periods of asystole for up to 2-4 seconds

Susie

25 mm/sec

ECG• Rhythm – arrhythmia• P wave (normal 1 box wide x 4 boxes tall)

– Some P waves missing and some inverted– Wandering pacemaker, failure of pacemaker and

acceleration of pacemaker in the SA node

Susie

25 mm/sec

ECG• PR interval – regular and normal• QRS and T waves - normal

Susie

25 mm/sec

ECG• Period of asystole nearly 5 seconds long

• Asystole longer than 2 seconds which resolves is aborted death

Susie

25 mm/sec

ECG• Period of asystole nearly 5 seconds long,


Susie

25 mm/sec

ECG• Period of asystole nearly 5 seconds long,


Susie

ECG• Period of asystole nearly 5 seconds long, • ended by an escape beat from the AV node• Asystole longer than 2 seconds which resolves is

aborted death

Susie

25 mm/sec

Diagnosis: Sick Sinus Syndrome

Sick Sinus Syndrome

• Periods of sinus arrest up to several seconds in length• Alternated with supraventricular tachycardia• Causes of sinus arrest

– A dying SA node (Sick Sinus Syndrome)– Markedly increased vagal tone

• AV node is often also abnormal– Normally escapes within 1 to 1.5 seconds (automaticity 40-60/min)

Diagnosis• Give atropine to rule out increased vagal tone• If no change, diagnosis is Sick Sinus Syndrome

Sick Sinus Syndrome

Treatment• Early in disease, may be responsive to atropine

– Atropine 0.04 mg/kg PO TID-QID – compounded w/ sweet syrup

– Not quite as effective:• Propantheline• Isopropamide• Darbazine - prochlorperazine plus isopropamide

– Mild side effects - mydriasis and constipation• Pacemaker usually eventually required to control syncope

Sick Sinus Syndrome

Treatment• Pacemaker usually eventually required to control syncope• Possible complications of pacemaker implantation

– infection– Lead dislodgement– Head and neck muscle twitch– Unknown generator life requiring replacement– Failure of sinus recovery if the pacemaker fails

Sick Sinus Syndrome



Sick Sinus Syndrome



Sick Sinus Syndrome



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 sounds well – muffled (

audio)

Jasper

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

Jasper


Jasper


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 thoraces• 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– Nucleated 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, T4 – normal except

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

Chest X-rays• Post-tap chest x-rays

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• No abnormalities notedShort Axis – LV PM

Jasper – Echo

Short Axis – LV apex• No abnormalities notedShort Axis – LV PM

Jasper – Echo

Short Axis – LV apex• 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

Jasper – Echo


Short Axis – Ao/RVOT

Jasper – Echo


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

Jasper – Echo


Jasper – Echo


Jasper – Echo


Jasper – Echo


Jasper – Echo


Jasper – Echo


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 – Echo


normal.• Lateral chest radiograph

Jasper – Echo


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, chest x-rays no change• Jasper declined all other diagnostics, without

deep sedation/anesthesia• May never do BUN, Electrolytes, recheck echo

Jasper – Echo

Long Term Follow-up• Jasper still doing well 18 months later• On lasix & enalapril only• At 2 years, owners decided Jasper didn’t need

heart meds anymore, so they stopped giving them• Jasper was asymptomatic for one year after that• Attacked and killed by dogs 3 years after initial

diagnosis• On necropsy, Jasper’s heart weighed 31g

– The normal adult cat heart should be <20g

Hypertrophic Cardiomyopathy

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

male cats• 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 >> arteries


Echocardiographic Abnormalities• Echo required in order to make diagnosis• LV and/or IVS thicker than 8-10 mm in diastole• Symmetrical or asymmetrical

– only a thick IVS (video)– primarily very thick papillary muscles (video)– Primarily apical







• LVIDD usually normal to slightly reduced• FS normal to increased, unless myocardial failure

developing (Jasper)• LVIDS sometimes 0 mm


Echocardiographic Abnormalities• LA often enlarged• RA sometimes also enlarged• “Smoke” may 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


Echocardiographic Abnormalities• HOCM with SAM

– Hypertrophic Obstructive CardioMyopathy with Systolic Anterior Motion

– Septal leaflet of the MV get sucked up into the LVOT during systole rather than closing the MV caudally

– Results in two compounded systolic murmurs• Aortic turbulence due to functional SAS• Mitral regurgitation

– SAM and its murmur can be intermittent

(video B mode) (video Doppler)


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


Follow-Up • 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(Client Handout)

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

Pleural Effusion

• Usually caused by biventricular failure in the dog– Parietal pleura veins drain into the R heart like the

systemic veins– Visceral pleura veins drain into the L heart with the

pulmonary veins• RHF alone can cause pleural effusion in dogs• LHF alone almost never causes pleural effusion

in dogs, but often does in cats– Cats in LHF will often have pleural effusion but no ascites– Dogs in RHF will often have pleural effusion and ascites

Documents

Practical Cardiology Case Studies