Increased arterial wave reflection may predispose syncopal attacks

Background: The incidence of syncope increases with age, while aging is als o associated with increased arterial wave reflection. Hypothesis: The study was undertaken to determine whether increased arteria l wave reflection is a predisposing factor of syncope. Methods: We recruited 38 patients (28 men and 10 women, mean age 57.2 +/- 2 0.3 years, range 17-87 years) with a history of syncope within 6 months of entry. The etiology of syncope was documented for each patient by a complet e assessment of vasomotor function and cerebral flow. All patients received a comprehensive echocardiographic evaluation of cardiac structure and func tion. Carotid augmentation index (AI) was estimated noninvasively with the tonometry technique. The results were compared with those from 54 age- and gender-matched controls. Results: The most frequent diagnoses of syncope were postural hypotension ( 13 patients) and cerebrovascular dysautoregulation (10 patients), and the c ause could not be determined in 9 patients. Compared with the control group , the syncope group had a greater AI (20 +/- 21 vs. 10 +/- 15%, p = 0.013). Subgroup analysis of 20 patients aged > 50 years and with the aforemention ed diagnoses showed even more striking results: AI, 29 +/- 10 vs. 11 +/- 15 %, p < 0.001. The enhanced augmentation in the patients remained when age, systolic blood pressure, height, and heart rate were accounted for. Analysi s of the carotid pulse wave suggested that both the timing and intensity of wave reflection were enhanced in patients with a history of syncope compar ed with controls. Conclusions: Our results support the hypothesis that enhanced arterial wave reflection is associated with the occurrence of syncope, especially in the elderly.