Right ventricular strain in patients with pulmonary embolism and syncope

Patients with acute pulmonary embolism (PE) can present with various clinical manifestations including syncope. The mechanism of syncope in PE is not fully elucidated and data of right ventricular (RV) function in patients has been limited. We retrospectively identified 477 consecutive patients hospitalized with acute PE diagnosed with a computed tomogram (CT) who also had a transthoracic echocardiogram (TTE) 24 h prior to or 48 h after diagnosis. Parameters of RV strain on CT, TTE, electrocardiogram (ECG), and clinical characteristics and adverse outcomes were collected. Patients with all three studies available for assessment were included (n = 369) and those with syncope (n = 34) were compared to patients without syncope (n = 335). Patients with syncope were more likely to demonstrate RV strain on all three modes of assessment compared to those without syncope [17 (50%) vs. 67 (20%); p = 0.001], and those patients were more likely to receive advanced therapies [9 (53%) vs. 15 (22%); p = 0.02]. PE-related mortality was highest among those presenting with high-risk PE and syncope (36%, OR 20.1, 95% CI 5.3-81.1; p < 0.001) and was low in patients with syncope without criteria for high-risk PE (3%, OR 1.2, 95% CI 0.2-10.0; p < 0.001). In conclusion, acute PE patients with syncope are more likely to demonstrate multimodality evidence of RV strain and to receive advanced therapies. Syncope was only associated with increased PE-related mortality in patients presenting with a high-risk PE. Syncope alone without evidence of RV strain is associated with low short-term adverse events and is similar to those without syncope.