35. Cardiovascular system (+ extra bits) Flashcards

1
Q

List three reasons why rx not accurate for cardiac evaluation

A

1) Variations in normal
2) Effect of positioning on appearance
3) Poor correlation between morphological and physiological abnormalities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which radiographic projections comparatively influence the appearance of the cardiac silhouette most profoundly? How / why?

A

DV vs VD

DV: Diaphragm billows forward, displacing heart cranially and to the left to a varying degree -> more pronounced in medium / large breeds

VD: Magnification of the heart in LARGE BREEDS due to distance from plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the vertebral heart scoring system. Why is it used?

A
  • Theoretically allows normlisation for body size

Technique:

  • Measure long axis and short axis -> SUM
  • Measure from cranial margin of T4

Normal: 8.7-10.7 (Too variable!)

**Up to 1.0 may vary with cardiac / resp cycle**

=> Best used for serial images in same patient

DOES NOT PERFORM BETTER THAN QUALITATIVE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the most common chamber dilation in the dog? Why?

A

LA -> Prevalence of MMVD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why does LA dilation result from L->R shunting?

A

Pulmonary overcirculation and VOLUME OVERLOAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In the DV projection, what structures are identified at the 12-1; 1-2; and 2-3 positions on the clock face? Where is the RA identified?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do dogs with LAE cough?

A

Possibly some inpingment from LA BUT USUALLY DUE TO CHONDROMALACIA

-> NO association between canine CHF and coughing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can LAE and TB LN+ be distinguished?

A

BOTH cause divergence of prinipal bronchi

LAE: Ventral to bifurcation

TB LN: Dorsal to bifurcation (typically)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

List radiographic features of LAE in the dog

A

Lateral:

Dorsocaudal bulge

Flattening / concavity of caudal margin

Loss of cardiac waste

DV:
Divergence of principal bronchi

“Double wall” - appearance of enlarged LA superimposed on heart

L Auricular enlargement / displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List radiographic features of LAE in the cat

A

**MAY APPEAR NORMAL**

Lateral:

  • Concavity of caudal margin

DV:
- Valentine shape heart -> Due to increased diameter of heart base. DOES NOT REFLECT BIATRIAL DILATION!!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

List features of LV enlargement (dog and cat same)

A

Lat:

  • Elongation -> Secondary elevation of trachea

=> Narrowing of angle between trachea and thoracic vertebrae

VD/DV:

  • Rounding of left heart border
  • Blunted apex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Provide examples that cause LV eccentric vs concentric hypertrophy

A

Eccentric => INC PRELOAD

  • PDA
  • MVD

Concentric => INC AFTERLOAD

  • Ao Stenosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cause of isolated RA enlargement?

A

RARE
Tricuspid dysplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Rx features of RAE

A

Lateral:

  • Enlargement at craniodorsal aspect -> NOTE may reflect enlargement of aorta or MPA

DV/VD

  • 9-11 o clock bulge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hypertrophy of which chamber may be identifiable radiographically?

A

RV -> More so than LV

Possibly due to thinner wall -> more obvious changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define the amount of sternal contact described in normal dogs of different breeds

A

Deep chested (Dobi, wolfhound): 1.5-2 ICS

Average dog: 2.5-3 ICS

Barrel chested (bulldog): 3-3.5 ICS

>3 often described to support RV enlargement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Rx features of RV Enlargement

A

Lat:

  • Increased sternal contact (Approx > 3 ICS)
  • Elevation of heart apex from sternum

DV/VD

  • Reverse D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 2 measures are used to determine CaVC enlargement?

A
  • diameter > length of 5th or 6th thoracic vertebral body
  • diameter > 1.5x descending Ao

=> NOTE: Variability with cardiac and resp cycle. Should be consistent finding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Rx features of Ao enlargement

A

Lat:
- Inc. mass at craniodorsal aspect

VD/DV:

  • Widening of precardiac mediastinum
  • Focal bulge (e.g. Ao stenosis, PDA)
  • **BEWARE** older cats with tortuous Ao, may be projected laterally to left, and appear as pulmonary nodule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Causes of RV hypertrophy

A

INC AFTERLOAD:

  • Pulm stenosis
  • Pulm hypertension (e.g. heartworm)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which projection is best used to evaluate the size of the cranial pulmonary arteries and veins?

A

LEFT LATERAL

=> in right lateral, often superimposed vessels interfere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which measures are used to evaluate peripheral pulm art and vvs?

A
  • Are they similar in size?
  • Relative to thickness of 9th rib
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

BOX: Enlarged pulm a and v

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the most common cause of pulm art distension without vein?

A

Pulmonary hypertension 2ry to HEARTWORM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

BOX: Pulm art enlargement ONLY

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the distribution of pulmonary vascular lesions most commonly seen in heartworm disease? What additional feature was commonly seen in cats with experimental heartworm?

A
  • CAUDAL vessels typically
  • R caudal more common than L caudal

=> CAN AFFECT ANY VESSEL / ALL VESSELS

**50% cats had persistent Bronchointerstitial pattern**

Similar to asthma -> consider these cases suspect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the most common cause of pulmonary TE?

A
  • HEARTWORM (…according to this book from US..)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the reported progression of PTE?

A
  • Heterogeneous pattern, becoming alveolar
  • MAY BE NORMAL
  • PERIPHERAL!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Typical radiographic features of heartworm?

A
  • MPA / Pulmonary artery enlargement
  • Pulmonary vessel tortuousity, “truncation” or “Pruning” (abrupt termination)
  • RV enlargement
  • Evidence of PTE
  • Signs of R heart failure
30
Q

What is the most common cause of pulm V enlargement only?

A
  • Mitral valve disease
31
Q

BOX: Enlargement of Pulm V ONLY

A
32
Q

BOX: Reduced size of both Pulm art and vv

A
33
Q

WHAT WORD SHOULD YOU USE WHEN DESCRIBING SMALL Vs and As?

A

HYPERLUCENT LUNG

34
Q

Describe pathophysiology of left heart failure inc. radiographic appearance

A
  • Reduced output -> increased end diastolic pressire in LV
  • Flows back into LA and Pulm V (Rx: Pulm v distension)
  • Eventually, transudation -> pulm parenchyma (Rx: Patchy unstructured interstitial pattern-> alveolar)
  • Oedema: Patchy, FOCAL (43/61 in 1 study), often dorsocaudal, uncommonly perihilar!
  • **MAY** cause pulm arterial hypertension -> backing up at capillaries, AND morphological changes to increase resistance to flow
35
Q

How does mitral valve jet location effect oedema?

A

Central jet: Symmetrical pulmonary changes

Eccentric: Assymetrical pulmonary changes

36
Q

Features of R heart failure?

A
  • Pleural effusion +- atelectasis
  • Hepatosplenomegaly
  • Ascites
37
Q

What are the 3 most common acquired cardiac lesions in clinical practice?

A
  • MMVD
  • Cardiomyopathy
  • Heartworm
38
Q

What poorly understood phenomenon is observed in canine DCM?

A
  • Mixed bronchointerstitial pattern (= atypical / peribronchial oedema)
  • > More classically seen with inflammatory disease
39
Q

List 4 breeds predisposed to DCM

A
  • Doberman
  • G Dane
  • Cocker
  • Boxer
40
Q

Rx features of DCM

A
  • Normal!
  • Generalised cardiomegaly
  • LAE
  • Pulm V +- A dilation (artery likely due to retenion as a result of decreased renal perfusion, and activation of RAAS)
  • R failure
  • Mixed bronchointerstitial pattern
41
Q

Rx features of HCM

A
  • LAtrial enlargement (valentine)
  • NORMAL LV as usually concentric change
  • Pulm v distension (rarer in cats)
  • Pulm oedema
  • Pleural effusion
42
Q

Rx features of pericardial effusion

A
  • Globoid
  • Clearly marginated
  • May contact walls of thorax if +++
  • R heart failure

=> if moderate may go undetected

43
Q

Rx signs of PDA

A
  • Dilation of proximal descending Ao
  • MPA and Pulm a + v enlargement
  • LA / auricular enlargement (Three knuckled appearance)
  • LV enlargement
44
Q

Rx features of PS

A
  • Dilation of MPA
  • RV enlargement
  • Normal / small pulm vessels (reduced CO)
45
Q

What type of Ao Stenosis is most common?

A

SUBVALVULAR > valvular

46
Q

Rx features of Ao stenosis?

A
  • DIlation of Ao arch
  • LV enlargement

+- LA enlargement

+- Pulm vessel enlargement (if mitral inufficiency)

MAY BE NORMAL

47
Q

Rx features VSD

A

DEPENDS ON VOLUME -> Typically quite dorsal, so empty directly into MPA

  • Mild RV Enlargement

+- mild pulm vessel enlargement

48
Q

Rx features of tricuspid dysplasia

A
  • RA enlargement

+- small pulm vessels if poor CO

49
Q

Causes of microcardia

A
  • Hypovolaemia
  • Dehydration (chronic)
  • Metabolic disease -> THINK ADDISONS!
50
Q

Detail formation of the cardiac atria

A
52
Q

Briefly, how does the interventricular septum form

A
53
Q

Detail the early embryological structures of the heart

A
54
Q

What do the endocardial cushions develop into?

A
  • Left and right AV ostia
55
Q

Embryology - PDA

A
56
Q

Embryology - ASD

A
57
Q

Embryology - PS

A
58
Q

Embryology - AS

A
59
Q

Embryology - AV dysplasias

A
60
Q

Embryology - Endocardial cushion defects

A
61
Q

Embryology - Conotruncal defects

A
62
Q

Embryology - Tetralogy / pentatology

A
63
Q

Embryology - NORMAL Aortic arch formation / other arteries

A
64
Q

Embryology - MOST COMMON VASCULAR RING

A
65
Q

Embryology - aberrant left subclavian

A
66
Q

Embryology - DOUBLE AORTIC ARCH

A
67
Q

Embryology - AORTIC COARCTATION

A
68
Q

Embryology - Cor triatriatum. Which type is more common?

A
  • Dexter more common
69
Q

Embryology - Name the major embryological components forming the vena cava. Which components fail to regress in persistent left CrVC and in duplication of the caudal VC?

A
70
Q

Label the major arteries

A
71
Q

Describe species differences in arterial supply to the brain

A
72
Q

List the 5 arteries supplying the different portions of the brain. Which vessels feed them?

A
73
Q

Briefly, detail the vertebral / paravertebral venous system

A