Current issues of ACP Journal Club are published in Annals of Internal Medicine


Etiology

Symptoms in patients with syncope did not predict death or recurrence

ACP J Club. 1999 Sept-Oct;131:53. doi:10.7326/ACPJC-1999-131-2-053


Source Citation

Oh JH, Hanusa BH, Kapoor WN. Do symptoms predict cardiac arrhythmias and mortality in patients with syncope? Arch Intern Med. 1999 Feb 22;159:375-80.


Abstract

Question

Do symptoms at the time of a syncopal episode predict death or syncope recurrence?

Design

Cohort study with a mean follow-up of 34.3 months.

Setting

A university medical center in Pittsburgh, Pennsylvania, USA.

Participants

275 participants who were ≥ 18 years of age (mean age 57 y, 58% women) and had an episode of syncope of unknown cause after history and physical examination. Exclusion criteria were initial pharmacologic or electrical cardioversion, failure to spontaneously regain consciousness, coma, shock, seizure disorder, vertigo, dizziness, or other states of altered consciousness.

Assessment of risk factors

20 symptoms at the time of the syncopal episode were assessed: dizziness, diaphoresis, nausea, vomiting, generalized weakness, visual changes, flushing, dyspnea, headache, chest pain, abdominal pain, palpitations, tingling, vertigo, lethargy, confusion, incontinence, aura, neurologic deficits, pruritus, and tonic-clonic movements. Heart disease, age, number of previous syncopal episodes, presence of trauma, duration of index syncopal episode, and initial abnormal findings on electrocardiography (ECG) were also assessed.

Main outcome measures

Recurrence of syncope and death. Death was assessed blindly at 3-month intervals. Cardiac arrhythmia was also assessed, but the assessors were not blinded.

Main results

Dyspnea, flushing, and previous syncope were associated with death at 1 year in univariate analyses (P < 0.05 for all associations). After adjustment for other risk factors, heart disease classification was associated with death at 1 year (Table). Vertigo, previous syncope, and ≥ 4 syncopal episodes in the previous year were associated with syncope recurrence in univariate analyses (P < 0.05 for all associations). After adjustment for other risk factors, syncopal recurrence was associated with age, previous syncopal episodes, and psychiatric history (Table).

Conclusions

In patients with syncope that was unexplained by history and physical examination, symptoms did not predict death or recurrence. Death was associated with heart disease at baseline; recurrence was associated with age, psychiatric history, and previous syncopal episodes.

Source of funding: In part, National Heart, Lung, and Blood Institute.

For correspondence: Dr. W.N. Kapoor, Montefiore University Hospital, Suite W933, 200 Lothrop Street, University of Pittsburgh Medical Center, Pittsburgh, PA 15213-2582, USA. FAX 412-692-4892.


Table. Risk factors for death and recurrence of syncope at 1 year*

Outcomes Risk factor Adjusted RRI (95% CI)†
Death Heart disease class 1 or 2 670% (60 to 3540)
Heart disease class 3 or 4 1250% (160 to 6950)
Recurrence Age ≤ 45 y 90% (10 to 240)
≥ 4 syncopal episodes in previous y 280% (110 to 600)
≥ 2 psychiatric diagnosis 130% (0 to 400)†

*Abbreviations defined in Glossary.
†Adjusted for age, number of previous syncopal episodes, cardiac comorbid conditions, trauma, duration of index syncopal episode, and initial findings on electrocardiography.
†CIs supplied by author.


Commentary

Medical histories, physical examinations, and ECG are presumed to play a key role in diagnosis of syncope and risk stratification of patients with syncope (1), but definitive evidence is lacking. Oh and colleagues studied 497 patients referred for syncope to a university medical center from 1987 to 1991. A noncardiogenic cause of syncope (i.e., vasovagal fainting, situational syncope, or orthostatic hypotension) was identified by history taking and physical examination alone in 222 patients. In the remaining 275 patients, assessment of symptoms was not found to be useful in predicting cardiac arrhythmia and death. In contrast, presence of cardiac disease and ECG abnormalities were excellent predictors of cardiogenic syncope and death at 1 year. Thus, history, physical examination, and ECG (3 readily available methods) can identify noncardiogenic causes of syncope in almost 50% of patients.

Symptoms alone do not stratify risk in the remaining patients (i.e., those with unexplained syncope). However, the use of full history, physical examination, and ECG can stratify risk in these patients (2). In this study, it is not clear whether history taking was standardized. When a standardized method of history taking is used, the predictive values for cardiogenic syncope compared with those for noncardiogenic syncope might be improved.

Wouter Wieling, MD
Academic Medical CenterAmsterdam, The Netherlands


References

1. Linzer M, Yang EH, Estes NA 3rd, et al. Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med. 1997;126:989-96.

2. Martin TP, Hanusa BH, Kapoor WN. Risk stratification of patients with syncope. Ann Emerg Med. 1997;29:459-66.