ABC | Volume 111, Nº1, July 2018

Original Article Carotid Sinus Massage in Syncope Evaluation: A Nonspecific and Dubious Diagnostic Method Tan Chen Wu, Denise T. Hachul, Francisco Carlos da Costa Darrieux, Maurício I. Scanavacca Instituto do Coração (InCor) - Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP - Brazil Mailing Address: Tan Chen Wu • Unidade de Arritmias Cardíacas do InCor-HC-FMUSP - Av. Dr Enéas de Carvalho Aguiar, 44. Postal Code 05403-000, São Paulo, SP - Brazil E-mail: tanchen.cardio@gmail.com , tan.wu@cardiol.br Manuscript received September 01, 2017, revised manuscript October 20, 2017, accepted December 08, 2017 DOI: 10.5935/abc.20180114 Abstract Background: Carotid sinus hypersensitivity (CSH) is a frequent finding in the evaluation of syncope. However, its significance in the clinical setting is still dubious. A new criterion was proposed by Solari et al. with a symptomatic systolic blood pressure (SBP) cut-off value of ≤ 85 mmHg to refine the vasodepressor (VD) response diagnosis. Objective: To determine and compare the response to carotid sinus massage (CSM) in patients with and without syncope according to standard and proposed criteria. Methods: CSM was performed in 99 patients with and 66 patients without syncope. CSH was defined as cardioinhibitory (CI) for asystole ≥ 3 seconds, or as VD for SBP decrease ≥ 50 mmHg. Results: No differences in the hemodynamic responses were observed during CSM between the groups, with 24.2% and 25.8% CI, and 8.1% and 13.6% VD in the symptomatic and asymptomatic groups, respectively (p = 0.466). A p value < 0.050 was considered statistically significant. During the maneuvers, 45 (45.45%) and 34 (51.5%) patients in the symptomatic and asymptomatic groups achieved SBP below ≤ 85 mmHg. Symptoms were reported especially in those patients in whom CSM caused a SBP decrease to below 90 mmHg and/or asystole > 2.5 seconds, regardless of the pattern of response or the presence of previous syncope. Conclusion: The response to CSM in patients with and without syncope was similar; therefore, CSH may be an unspecific condition. Clinical correlation and other methods of evaluation, such as long-lasting ECG monitoring, may be necessary to confirm CSH as the cause of syncope. (Arq Bras Cardiol. 2018; 111(1):84-91) Keywords: Syncope; Carotid Sinus / physiopathology; Accidental Falls; Aged; Hypotension. Introduction Carotid sinus hypersensitivity (CSH), an age-related phenomenon, is rarely diagnosed in patients under the age of 50 years. 1 It has been accepted as a cause of syncope and unexplained falls in the elderly, with prevalence as high as 45% in some reports. 2 The clinical relevance of a positive response to carotid sinus massage (CSM) in patients with syncope is still controversial, in spite of the previous publications. Although the reported prevalence of CSH in patients with syncope is 23% to 41%, 3-8 it has been described in 17% of normal subjects, in 20% of patients with cardiovascular disease, and in 38% of patients with severe carotid artery disease. 9-11 Recently, some reports have proposed a modification of the diagnostic criterion according to hemodynamic findings during CSM, 12,13 with a cut-off value of symptomatic systolic blood pressure (SBP) of ≤ 85 mmHg to determine a vasodepressor (VD) form, instead of the current definition of 50 mmHg SBP fall. To clarify the practical implications of CSM and CSH in syncope evaluation, this study was aimed at determining CSH prevalence and analyzing the patterns of the hemodynamic responses to CSM and symptoms in patients older than 50 years with and without symptoms of syncope or presyncope seen in a tertiary referral unit. Methods The scientific and ethics committees of our institution approved this study. Written informed consent was obtained from each participant. Patients aged 50 years or older with at least two episodes of syncope or presyncope in the previous year, referred to the Arrhythmia and Syncope Unit of the Instituto do Coração (InCor) – University of São Paulo Medical School Hospital were selected as the symptomatic group. The number of patients was determined by convenience sampling. Patients presenting with structural heart disease, such as dilated cardiomyopathy with a left ventricular ejection fraction ≤ 50%, moderate or significant valvular disease, myocardial infarction in the previous 6 months, unstable angina, stroke, carotid bruit or previously diagnosed carotid artery stenosis were excluded. Patients on chronic 84