DCM

Question 1

Potential underlying causes

Answer 1

o Carnitine deficiency
o Metabolic disorders: hypoT4
o Myocarditis
o Taurine deficiency
o Hereditary/familial

Question 2

Taurine deficiency

Answer 2

 Cause of DCM in cats. Now rare in felines since taurine supplementation in commercial diet.
* Still recognized in some cats eating normal diet (10% of CM). Unknown cause.
o Infectious etiology suggested
o Histopath suggestive of myocarditis
 Dogs: plasma taurine levels are normal to high
* Except Cocker Spaniel

Question 3

Hereditary familial DCM breeds

Answer 3

 Doberman
 Boxer
 English ocker Spaniels
 Portuguese water dogs → young puppies
 Newfoundlands

Question 4

Features

Answer 4

poor systolic function + ventricular dilation

Question 5

What is occult DCM

Answer 5

before c/s develop
o May last several years
o VPCs common finding

Question 6

2D echo breed differences

Answer 6

o Dalmatian: more ventricular/atrial dilation than any breed
o Boxers: may have normal ventricular size with poor systolic function
o Dobermans: less R sided involvement than other breeds
 LVIDd >46mm, LVIDs > 38mm, FS < 25%

Question 7

2D echo features

Answer 7

Systolic dysfct
incr chamber size

Question 8

2D echo: systolic dysfct parameters

Answer 8

o Usually diffuse
o Some area may exhibit better function

 ↑PEP
 ↓ ET
 ↓ Vcf
 ↓FS
* FS alone should not be use as dx criteria
o Pre/afterload dependent: ↓ if
 ↓ preload
 ↑ afterload
o Transient depression can occur normally
 PEP/ET ratio ↑: slow rate of pressure rise during IVCT
 ↓mitral annulus motion
* DCM 0.27-1.06cm
* Normal 0.46-1.74

Question 9

Cats DDX DCM

Answer 9

• HCM with myocardial infarct → regional wall hypokinesis
• UCM

Question 10

2D echo chamber size

Answer 10

o ↑ internal dimensions in diastole/systole
 Cats: >11mm in systole, >16mm in diastole
 Early DCM: ↑ dimensions only in systole as FS ↓
 Diastolic ↑ dimensions: as fct deteriorates and ↓ forward flow
o ↑ EPSS
 Poor contraction → ↑ end systolic volume → ↑ filling pressures → limit flow from LA to LV → ↓ mitral excursion → ↑ EPSS
 Distance btw max early diastolic motion (E point) of septal MV leaflet to IVS
 Sensitive and specific sign of DCM = always present
* >6.5mm abnormal in Dobe
* >4mm in cats
 B bump: end of MV diastolic motion
* Sign of ↑ LV end diastolic P
o LA/RAE as myocardial failure progresses

Question 11

2D echo: wall thickness

Answer 11

• LVFW and IVS thickness usually thin
  o May be normal
  o Lack of compensatory hypertrophy: ↑ LV afterload as ventricle dilates → ↑ wall stress
   ↓FS and Vcf

Question 12

2D echo: sphericity

Answer 12

↑ as LV dilation occurs → chamber becomes more spherical
o LV length from 4 chamber view
o LVIDd on M-mode
o Normal 1.78 +/- 0.16

Question 13

Doppler echo

Answer 13

• Mitral regurgitation → annular dilation
• Relaxation abnormalities on mitral inflow patterns

Question 14

What can a 1st sign of DCM

Answer 14

• Cardiac arrhythmias may be 1st sign
  o W or w/o normal cardiac enlargement

Question 15

Scoring system for subclinical DCM

Answer 15

> 6 points suggestive of sublinical DCM
o Major criteria = 3 points
 Systolic/diastolic LV dilation
 ↑ sphericity <1.65
 ↓FS <20-25% depending on breed
 EF from Simpson’s method (R LAX view) <40%
* More sensitive than M-mode to detect early changes in Dobe
* LV volume estimates cutoff
o End diastolic volume/BSA >95ml/m2
o End systolic volume/BSA >55ml/m2

o Minor criteria = 1 point
 Arrhythmias in Boxers/Dobermans
 Afib
 ↑EPSS
 PEP/ET <0.4
 Equivocal FS 20-25%, but <30%
 LA/biatrial dilation

Question 16

Predictors of outcome

Answer 16

• Degree of Lv dilation/EPSS/FS → not predictor of survival time
• Poorer survival time: at dx
  o CHF (pulmonary edema, pleural effusion, ascites)
  o Young age
  o Restrictive inflow pattern →↑LV filling pressures
   ↑E wave, rapid deceleration, ↓A wave
   E wave deceleration <80ms correlated w poor survival