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 Table 3 – Proportions of patients with systolic blood pressure (SBP) ≤ 85 mmHg in the series of carotid sinus massage (CSM). Minimum SBP ≤ 85 mmHg during CSM Right CSM 1 n (%) Right CSM 2 n (%) Left CSM 1 n (%) Left CSM 2 n (%) Total n (%) Asymptomatic 24 (36.3) 24 (36.3) 20 (30.3) 16 (30.3) 66 (100) Symptomatic 33 (33.3) 34 (34.3) 26 (26.2) 29 (29.2) 99 (100) Table 4 – Correlation between occurrence of symptoms during carotid sinus massage and the value of minimum systolic blood pressure (SBP) and maximum RR interval obtained during the massage Symptoms Mean ± SD Median Minimum Maximum n p Minimum right SBP (mmHg) asymptomatic 102.5 ± 12.9 101 59 180 106 < 0.001* symptomatic 86.4 ± 23.6 85 42 151 59 Total 96.7 ± 23.7 96 42 180 165 Minimum left SBP (mmHg) asymptomatic 101.8 ± 20.7 98 64 185 106 < 0.001* symptomatic 89.0 ± 20.3 87,5 51 178 58 Total 97.3 ± 21.4 95 51 185 164 Maximum right RR interval (ms) asymptomatic 1326 ± 768 1154 625 5455 106 < 0.000# symptomatic 2639 ± 1762 1800 880 7500 59 Total 1795 ± 1369 1225 625 7500 165 Maximum left RR interval (ms) asymptomatic 1238 ± 564 1111 6326 4520 106 < 0.000# symptomatic 2772 ± 1891 1840 811 8160 59 Total 1786 ± 1419 1200 632 8160 165 SD:standard deviation; * Student’s t Test; # Mann-Whitney test. The immediate reproducibility of the CSM response was evaluated by repeating the CSM during the same procedure. The heart rate response reproducibility was slightly superior as compared to the blood pressure response, with intraclass correlation coefficients of 0.68 for the right ΔSBP, 0.71 for the left ΔSBP, 0.83 for the right ΔRR, and 0.81 for the left ΔRR. The heart rate data demonstrate acceptable levels of conformity (above 0.75). Reproducibility of the abnormal blood pressure response (VD CSH) was observed in 40.8% (20/49 cases), and the abnormal heart rate response (CI CSH) in 48.5% (50/103 cases). Discussion The diagnosis and management of syncope are still a challenging task in medical practice. In elderly patients, identifying the underlying diagnosis may be more complex due to multiple comorbidities, atypical presentations, amnesia from loss of consciousness, and difficulties in remembering and characterizing the episode. The occurrence of OH is an important risk factor for falls and syncope, especially in the elderly, with 18.2% of prevalence. 20-23 In this study, we observed more than twice the prevalence (29.2% vs. 12.1%) of OH in the symptomatic patients compared to the asymptomatic patients. This finding confirms the importance of investigating OH in aged patients with syncope, reinforcing OH as one of the most frequent causes of syncope in the elderly. Differently from the results observed in the search of OH, similar responses were obtained during CSM in symptomatic and asymptomatic groups. This finding perhaps reinforces the hypotheses that CSH is not a diagnostic marker of a clinical syndrome. With a similar proposal to assess the prevalence of CSH and the diagnostic value of CSM, Tan et al. 24 have found altered responses in 25% of the patients referred for evaluation of syncope and unexplained falls. This prevalence of CSH was lower when compared to the prevalence in another report 25 in individuals older than 65 years, randomly sampled from an unselected community. In that study, the authors observed CSH in 39% of the patients, and, in a subgroup of patients with no history of syncope or falling, 35% had a hypersensitive response to CSM, and 36% had CSM-related symptoms. Thus, a positive test for CSHmay not necessarily determine the cause of fainting, leaving the clinician with the difficult decision whether to accept the test as a confirmation of the cause of syncope, which sometimes might induce an incorrect diagnosis. Solari et al. 26 have proposed a cut-off value of symptomatic SBP ≤ 85 mmHg as more appropriate to identify the VD form of CSH in a study with 164 patients with CSM who produced spontaneous symptoms in the presence of hypotension or bradycardia (Method of Symptoms), or diagnosis of carotid sinus syndrome. The method does not require any cut-off value of asystolic pause or of the SBP fall induced by CSM, as positivity of the test is based on the reproduction of symptoms. They concluded that one third of patients with isolated VD form could not be identified 88