Syncope: poor LV function increased the risk of sudden death.

Clinical bottom line (level 1b)

  1. Around 10% of patients with syncope who were referred to arrhythmia clinic died suddenly in the following two years.
  2. The risk was increased in patients with a left ventricular ejection fraction < 30%.
Middlekauf et al: American Heart Journal 1993; 125: 121-125
Expires October 2004

The study

Prospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: arrhythmia clinic, university hospital, USA

88 patients (aged mean 57 years, ?% male) referred for electrophysiological investigation of syncope (mean LVEF 41%)


Multivariate analysis performed on prognostic factors.

100% followed for mean 2 years
Outcomes studied:
  • sudden death

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    sudden death mean 2 years 10/88 11%
    (4.7% to 18%)

    prognostic factor for
    sudden death     		time to outcome unadjusted RR
    (95% CI)
    left ventricular ejection fraction < 30% mean 2 years 2.4
    ( to )

    Comments

    1. Highly selected group of patients (7% transplanted, 56% with cardiac cause for syncope cf ~25% in Kapoor studies) makes extrapolation difficult.
    2. The study is too small to differentiate prognosis by cause of syncope.
    3. Is LVEF <30% an independent predictor of death regardless of the cause of syncope?

    Citation

    1. Middlekauf HR, et al: Prognosis after syncope: impact of LVF. American Heart Journal 1993; 125: 121-125
    Contributor: Bob Phillips and Chris Ball, October 2000
    Reviewer:

    Clinical Question.
    Patient syncope
    Intervention or Exposure risk factor
    Outcome death