Syncope in patients with pulmonary embolism: comparison between patients with syncope as the presenting symptom of pulmonary embolism and patients with pulmonary embolism without syncope

Abstract: Syncope as an initial presentation of pulmonary embolism occurs in 10% of patients.We compared clinical and instrumental parameters in patients with syncope as the presentingsymptom of pulmonary embolismand in patients with documented pulmonary embolismwithoutsyncope. Seventy patients with the diagnosis of pulmonary embolismand apparently stableclinical conditions were evaluated. They were divided in two groups: 10 patients with syncopeas the presenting symptom of pulmonary embolism (group 1) and 60 patients without syncope(group 2). Patients with syncope showed a more pronounced tendency to present with mainpulmonary artery embolus than patients without syncope (contingency coefŽ cient ˆ 0.301,p < 0.04; one-tailed). However, despite the evidence that patients with syncope have signiŽ cantreductions in systolic and=or diastolic blood pressure, shock was not observed in any patient. Inno case was thrombolytic treatment given and all patients received standard anticoagulationwith unfractioned heparin and oral anticoagulant. We suggest that syncope in the setting ofnon-massive pulmonary embolism may be due to vaso-vagal mechanism that can lead to areduction of arterial blood pressure when central artery thrombosis is involved.