Restrictive Cardiomyopathy

Question 1

Definition of restrictive cardiomyopathy (RCM)?

Answer 1

Impaired ventricular filling with reduced diastolic volume of either or both ventricles with normal or near normal systolic function and wall thickness

Question 2

Causes of RCM?

Answer 2

Myocardial Causes:
- Non-infiltrative (e.g. idiopathic)
- Infiltrative (e.g. amyloidosis, sarcoidosis)
- Storage disease (e.g. haemochromatosis)
Endomyocardial Causes:
- Endoymocardial fibrosis
- Radiation

Question 3

Most common cause of RCM in developed countries?

Answer 3

Cardiac amyloidosis

Question 4

Infiltrative vs non-infiltrative causes of RCM?

Answer 4

• Non-infiltrative: abnormal myocardium leads to increased myocardial stiffness leading to RCM
• Infiltrative and storage disorders: infiltration or deposition of pathologic substances between myocardial cells = increased wall thickness and stiffness

Question 5

Causes of abnormal diastolic function in RCM?

Answer 5

• Increased myocardial stiffness
• Poor chamber compliance
  (When stiff, non-compliant ventricle = restricted diastolic filling = ventricular filling occurs rapidly in early diastole but terminates abruptly at end of rapid filling phase due to relatively fixed limit of volume of ventricles)
• RCM does not always produce restrictive haemodynamics

Question 6

Ventricular systolic function in RCM?

Answer 6

• Normal in early stages of disease
• Deteriorates as disease progresses

Question 7

Anatomic features of RCM?

Answer 7

• Normal sized ventricles
• Marked biatrial dilatation (caused by marked elevation in a trial pressure secondary to restricted diastolic filling of ventricles)

Question 8

What is the role of echo in RCM?

Answer 8

1. Establishing the diagnosis of RCM
2. Assessment of ventricular size and systolic function
3. Evaluation of LV diastolic function

Question 9

Echo features of RCM?

Answer 9

• Marked biatrial enlargement with normal sized ventricles
• Normal/near normal systolic function in early stages; deteriorates as disease progresses
• Small circumferential PE often also seen
• Increased ventricular wall thickness
• Variable grades of diastolic dysfunction (may be grade I, II or III)

Question 10

Diastolic dysfunction in CP vs RCM?

Answer 10

• CP: Stiff non-compliant pericardium causes diastolic dysfunction
• RCM: Stiff non-compliant muscle causes diastolic dysfunction
• High ventricular filling pressures with normal systolic function in both

Question 11

CP vs RCM: Treatment

Answer 11

• CP: A treatable cause of diastolic heart failure
• RCM: No satisfactory therapy, poor prognosis

Question 12

CP vs RCM: Mitral inflow

Answer 12

• CP: ≥ 25% respiration variation in E
• RCM: respiratory variation absent

Question 13

CP vs RCM: DTI annular e’ velocities

Answer 13

• CP: normal or increased
• RCM: decreased

Question 14

CP vs RCM: lateral e’ vs septal e’

Answer 14

• CP: lower lateral e’ (annulus reversus)
• RCM: lateral e’ higher

Question 15

CP vs RCM: Relationship between LVFP and E/e’

Answer 15

• CP: low E/e’ when LVFP increased = annulus paraxodus
• RCM: high E/e’ when LVFP high

Question 16

CP vs RCM: Flow propagation (Vp)

Answer 16

• CP: fast ≥ 100cm/s
• RCM: slow < 45cm/s

Question 17

CP vs RCM: Tricuspid inflow

Answer 17

• CP: ≥ 40% respiratory variation in R
• RCM: respiratory variation absent

Question 18

CP vs RCM: Hepatic venous flow

Answer 18

• CP: Expiratory decrease in diastolic flow
• RCM: no variation in diastolic flow

Question 19

CP vs RCM: Septal ‘bounce’

Answer 19

• CP: Yes
• RCM: No

Question 20

CP vs RCM: Signs of infiltration

Answer 20

• CP: Not present
• RCM: May be present

Question 21

CP vs RCM: Pericardial appearance

Answer 21

• CP: thickened
• RCM: normal