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.