Causes
Clinical
features
Investigations
Therapy
Prognosis
|  | | | Investigations |
If there is no clear cause, consider Holter monitoring
b
 worn for at least 24 hours
c
Why?
-
Holter monitoring over 72 hours detects twice as many arrhythmias as 24 hours worth
c
-
It can help diagnose a cause in 27% of cases (95% CI: 21% to 33%)
b
|
day
c
|
major arrhythmia detected
(95% CI)
|
|
1
|
15%
(8.3% to 23%)
|
|
2
|
11%
(5.1% to 20%)
|
|
3
|
4.2%
(0.8% to 12%)
|
Note:
-
Symptoms of dizziness and fainting are common in patients with syncope, but few are associated with arrhythmias
(1.0%: 95% CI:
0.49% to 1.5%)
c
Dizziness and fainting make a major arrhythmia less likely
| Patient |
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
LR-
(95% CI)
|
Post-test Probability |
|
unexplained syncope
c
(pre-test probability: 9%)
|
major arrhythmia
(24 hour ECG)
|
dizziness and fainting
|
0.25
(0.12 to
0.56)
|
2% |
1.2
(1.1 to
1.2)
|
10% |
|
internal medicine