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A prospective evaluation and follow-up of patients with syncope
Insights
Identifying the cause of syncope is crucial for prognosis. Cardiovascular causes of syncope significantly increase the risk of mortality and sudden death compared to noncardiovascular or unknown causes.
Area of Science:
- Cardiology
- Internal Medicine
- Clinical Research
Background:
- Syncope, a transient loss of consciousness, presents diagnostic challenges.
- Establishing the etiology of syncope is vital for patient management and risk stratification.
Purpose of the Study:
- To determine the proportion of syncope cases with an established cause.
- To define the 12-month prognosis, including mortality and sudden death, based on syncope etiology.
Main Methods:
- Prospective evaluation of 204 patients presenting with syncope.
- Categorization of syncope causes into cardiovascular, noncardiovascular, and unknown.
- Follow-up for 12 months to assess mortality and incidence of sudden death.
Main Results:
- A cause was established in 107 patients (53 cardiovascular, 54 noncardiovascular); syncope remained unexplained in 97.
- Overall 12-month mortality was 14%.
- Patients with cardiovascular syncope had significantly higher mortality (30%) and sudden death incidence (24%) compared to noncardiovascular (12% mortality, 4% sudden death) and unknown causes (6.4% mortality, 3% sudden death).
Conclusions:
- Syncope etiology can be determined in a significant proportion of patients.
- Cardiovascular causes of syncope are associated with a markedly poorer prognosis, including a higher risk of sudden death.
- Diagnostic categorization of syncope has important prognostic implications.
Abstract:
We prospectively evaluated and followed 204 patients with syncope to determine how often a cause of syncope could be established and to define the prognosis of such patients. A cardiovascular cause was established in 53 patients and a noncardiovascular cause in 54. The cause remained unknown in 97 patients. At 12 months, the overall mortality was 14 +/- 2.5 per cent. The mortality rate (30 +/- 6.7 per cent) in patients with a cardiovascular cause of syncope was significantly higher than the rate (12 +/- 4.4 per cent) in patients with a noncardiovascular cause (P = 0.02) and the rate (6.4 +/- 2.8 per cent) in patients with syncope of unknown origin (P less than 0.0001). The incidence of sudden death was 24 +/- 6.6 per cent in patients with a cardiovascular cause, as compared with 4 +/- 2.7 per cent in patients with a noncardiovascular cause (P = 0.005) and 3 +/- 1.8 per cent in patients with syncope of unknown origin (P = 0.0002). Patients with syncope can be separated into diagnostic categories that have prognostic importance. Patients with a cardiovascular cause have a strikingly higher incidence of sudden death than patients with a noncardiovascular or unknown cause.