ABC | Volume 111, Nº1, July 2018

Original Article Wu et al Carotid sinus massage in syncope evaluation Arq Bras Cardiol. 2018; 111(1):84-91 use of beta-blockers, digitalis, calcium channel blockers or alpha‑methyldopa, who could not discontinue them, as well as patients with an artificial pacemaker, were also excluded. For the asymptomatic group, 66 patients with no history of syncope or presyncope were selected from the geriatric outpatient clinic of the same institution. The exclusion criteria for the group were the same as those applied to the symptomatic group. Carotid sinus massage Carotid sinus massage was performed from 1:00 pm to 5:00 pm. Cardiac medications, such as beta-blockers, calcium channel blockers (diltiazem and verapamil), digoxin and alpha‑methyldopa, were discontinued 3 days before the procedure. All CSM were performed by the same physician. Continuous electrocardiogram and noninvasive, beat‑to‑beat blood pressure were recorded by digital photoplethysmography (Finapres Monitor® Ohmeda, USA) 14 or a vascular unloading device (Task Force Monitor ® CNSystems Medizintechnik GmbH, Graz, Austria). 15-17 Blood pressure was monitored in the first 3 minutes with the patient in the 70° upright position on a footplate-assisted tilt table to evaluate the presence of orthostatic hypotension (OH), which was defined as a postural drop in SBP of at least 20 mmHg or a drop in diastolic blood pressure (DBP) of at least 10 mmHg within the first 3 minutes of standing. 18 Carotid sinus massage was performed for 5 seconds, in the 70° upright position after 5 minutes of standing, following the stabilization of blood pressure and heart rate, and at the point with the maximal carotid pulse on the anterior margin of the sternocleidomastoid muscle. Blood pressure and heart rate were monitored throughout. Right-sided CSM was followed by left-sided CSM (or vice versa) after at least 1 minute or as long as the heart rate and blood pressure values returned to baseline. The CSM was performed twice in each side to evaluate the reproducibility of the method. The sequence was completed even in the event of positivity of 1 massage. After each episode of CSM, patients were questioned about symptoms related to the maneuver. Cardioinhibitory (CI) CSH was defined as asystole of 3 seconds or more, and VD CSH was defined as a drop of 50 mmHg or more in SBP. 19 Blood pressure was recorded continuously immediately before each CSM until it reached the lowest value recorded during or shortly after the maneuver. The magnitude of the blood pressure response was obtained by the difference between the baseline SBP and the minimum SBP during CSM (ΔSBP). Likewise, RR intervals were recorded, and the magnitude of heart rate response was given by the difference between the RR interval before CSM and the maximum RR interval during CSM (ΔRR). Statistical analysis The data were analyzed by using Excel 2003 and SPSS software for Windows, version 15.0. The nominal measures are presented in absolute (n) and relative (%) frequencies, and numerical measurements are described as mean, standard deviation, median, minimum and maximum values. The clinical characteristics and responses toCSM (the order, result and symptoms associated with CSM) were compared between groups by using the chi-square test and the likelihood ratio test. The numerical measurements between the groups were summarized by descriptive statistics and compared by using Student t test, chi-square test for categorical data, and Mann‑Whitney test for continuous data. Nonparametric tests were used in the absence of normally distributed data assumption (Kolmogorov-Smirnov test). The intraclass correlation coefficient was used to analyze the reproducibility of the CSM response. A p value of < 0.050 was considered statistically significant. Results In the symptomatic group, almost all patients (93.9%) had syncope, with an average of 5.4 episodes (median - 3) in the year prior to evaluation. The baseline clinical characteristics of the 99 patients in the symptomatic group and the 66 patients in the asymptomatic group are shown in Table 1. Patients in the symptomatic group had the most significant decreases in blood pressure after being tilted to 70°. The mean SBP and DBP changes after orthostatic stimulus are shown in Figure 1. The symptomatic group had more occurrences of OH (29 patients, 29.2%), of whom, 19 patients met the diagnostic criterion of a SBP decrease ≥ 20 mmHg, and 10 additional patients met the criterion of a DBP decrease ≥ 10 mmHg. Only 8 patients (12.1%) in the asymptomatic group had a diagnosis of OH, which was due to decreased SBP in 7 of them (p = 0.014). Carotid sinus massage There was no difference between the groups in the responses obtained during CSM (p = 0.466) (Figure 2). The response to CSM was considered normal in 64.8% of patients in the entire sample, 67.7% in the symptomatic Table 1 – Clinical characteristics of the symptomatic and asymptomatic groups. Variable Symptomatic (n = 99) Asymptomatic (n = 66) p Age, mean ± sd (median) (minimum – maximum) 69.67 ± 10.26 (70) (50–93) 73.01 ± 9.68 (74) (52–92) 0.037 Male, n (%) 41 (41.4%) 23 (34.8) 0.396 Hypertension 73 (73.7%) 54 (81.8%) 0.227 Diabetes 13 (13.1) 20 (30.3) 0.007 Coronary artery disease 5 (5.1) 11(16.7) 0.014 chi-square test; sd: standard deviation. 85