|
Technical factors
|
|
Image quality
|
|
Position of sample volume
|
|
Physiological factors
|
|
Heart rate
|
|
Respiration
|
|
Position
|
|
Preload
|
|
Valsalva maneuver
|
|
Age
|
|
Pathological causes
|
|
Non-cardiac
|
|
Obesity
|
|
Deconditioning
|
|
Chronic obstructive airways disease
|
|
Sleep apnoea
|
|
Renal failure
|
|
Cardiac
|
|
See Table 2 and Figure 6
|
- Each of the factors mentioned could confound Doppler interpretation. So these factors should be eliminated or their effects should be factored in. The list is not exhaustive and the non-cardiac causes could also affect cardiac function.
