Practical Cardiology
Case Studies
Wendy Blount, DVM
Nacogdoches 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
CBC, mini-panel, electrolytes
• Normal
Daisy
CBC, mini-panel, electrolytes
• Normal
Daisy
CBC, mini-panel, electrolytes
• Normal
Thoracic 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 beat
9mm 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
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
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
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 3040 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 3040 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
Bloodwork
• CBC, electrolytes normal
• BUN 105, creat 2.1
Chest x-rays
Daisy
Bloodwork
• CBC, electrolytes normal
• BUN 105, creat 2.1
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
Long View – 4 Chamber
• LV and LA both appear large
• MV is very thick and knobby, with some
prolapse into the LA
Daisy - Echo
Long View – 4 Chamber
• LV and LA both appear large
• MV is very thick and knobby, with some
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)
Susie
Signalment
• 12 year old spayed miniature schnauzer
Chief Complaint
• Episodes of Confusion
Exam
• 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
Vertebral
Heart Size
= 10.7
(normal
8.5-10.5)
Enlarged
main
pulmonary
artery
Susie
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
25 mm/sec
Susie
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
25 mm/sec
Susie
ECG
• PR interval – regular and normal
• QRS and T waves - normal
25 mm/sec
Susie
ECG
• Period of asystole nearly 5 seconds long
• Asystole longer than 2 seconds which resolves is
aborted death
25 mm/sec
Susie
ECG
• Period of asystole nearly 5 seconds long,
• Asystole longer than 2 seconds which resolves is
aborted death
25 mm/sec
Susie
ECG
• Period of asystole nearly 5 seconds long,
• Asystole longer than 2 seconds which resolves is
aborted death
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
Diagnosis: Sick Sinus Syndrome
25 mm/sec
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
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
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
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
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
Immediate Diagnostic Plan:
• Lasix 25 mg IM – then in oxygen cage
• When RR <50, lateral thoracic radiograph
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 thoraces
• Removed 400 ml of pink opaque fluid that
resembled Pepto bismol
• Fluid had no “chunks” in it
Differential 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 noted
Short Axis – LV PM
Jasper – Echo
Short Axis – LV apex
• No abnormalities noted
Short Axis – LV PM
Jasper – Echo
Short Axis – LV apex
• No abnormalities noted
Short 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 – MV
• No abnormalities noted
Short Axis – Ao/RVOT
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
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
Jasper – Echo
Short Axis – PA
• Difficult to evaluate due to “rib shadows”
Long Axis – 4 Chamber
• Hyperechoic “thingy” in the LA, with smoke
Long 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
Recheck – 1 week
• Jasper doing exceptionally well –back to
normal.
• Lateral chest radiograph
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, 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
Hypertrophic Cardiomyopathy
Radiographic Findings
• + LV enlargement
– Elevated trachea, increased VHS
• LA + RA enlargement seen on VD in cats
• + LHF
– Pleural effusion
– Pulmonary edema
– Lobar veins >> arteries
Hypertrophic Cardiomyopathy
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
Hypertrophic Cardiomyopathy
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
Hypertrophic Cardiomyopathy
Echocardiographic Abnormalities
• Echo required in order to make diagnosis
• LV and/or IVS thicker than 9-10 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
Hypertrophic Cardiomyopathy
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
Hypertrophic Cardiomyopathy
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)
Hypertrophic Cardiomyopathy
DDx LV thickening
• Hypertension
• Hyperthyroidism
• (Chronic renal failure)
• Only HCM causes severe thickening of LV
Dogs can rarely have HCM
• Cocker spaniels
Hypertrophic Cardiomyopathy
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
Hypertrophic Cardiomyopathy
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
Hypertrophic Cardiomyopathy
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)
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