ABC | Volume 114, Nº2, February 2020

Original Article Lacerda et al. Mortality in cardioinhibitory carotid sinus hypersensitivity Arq Bras Cardiol. 2020; 114(2):245-253 Table 1 – Baseline characteristics of the patients with and without CICSH 42 patients lost to follow‑up (without CICSH) 408 patients without CICSH 52 CICSH patients 52 CICSH x 408 without CICSH P value. OR (95% CI) Male sex 14/42 (33.3%) 206/408 (50.5%) 39/52 (75.0%) 0.001 OR: 2.94 (1.52–5.67) Age (mean ± SD) 65.4 ± 10.4 64.93 ± 9.74 66.31 ± 8.15 0.33 Age ≥ 65 years 20/42 (47.6%) 203/408 (49.8%) 31/52 (59.6%) 0.18 Heart rate before CSM (mean ± SD) 68.6 ± 13.6 68.7 ± 14.19 62.4 ± 15.6 0.003 Unexplained falls or syncope in the year preceding CSM 8/42 (19.0%) 56/408 (13.7%) 7/52 (13.5%) 0.95 Structural heart disease 19/42 (45.2%) 277/408 (67.9%) 46/52 (88.5%) 0.002 OR: 3.62 (1.51–8.70) Atherosclerosis 18/42 (42.8%) 198/408 (48.5%) 37/52 (71.2%) 0.002 OR: 2.61 (1.39-4.91) History of AMI 10/42 (23.8%) 128/408 (31.4%) 28/52 (53.8%) 0.001 OR: 2.55 (1.42-4.58) Previous myocardial revascularization 5/42 (11.9%) 88/408 (21.6%) 20/52 (38.5%) 0.007 OR: 2.27 (1.23-4.17) Previous CABG 2/42 (4.8%) 58/408 (14.2%) 16/52 (30.8%) 0.002 OR: 2.68 (1.40-5.14) Previous PCI 3/42 (7.1%) 30/408 (7.4%) 4/52 (7.7%) 0.93 Atrial fibrillation 2/42 (4.8%) 20/408 (4.9%) 2/52 (3.8%) 0.73 Normal ECG 13/42 (31%) 112/408 (27.5%) 8/52 (15.4%) 0.06 Negative chronotropic drug use 28/42 (66.6%) 235/408 (57.6%) 40/52 (76.9%) 0.007 OR: 2.45 (1.25-4.18) Hypertension 29/42 (23.8%) 311/408 (76.2%) 40/52 (76.9%) 0.91 Diabetes 10/42 (26.2%) 93/408 (22.8%) 14/52 (26.9%) 0.51 Dyslipidemia 20/42 (47.6%) 215/408 (52.7%) 35/52 (67.3%) 0.046 OR: 1.84 (1.00-3.40) Smoking 7/42 (16.7%) 41/408 (10%) 10/52 (19.2%) 0.047 OR: 2.13 (0.99-4.56) CICSH: cardioinhibitory carotid sinus hypersensitivity; OR: Odds ratio; CSM: carotid sinus massage; AMI: acute myocardial infarction; CABG: coronary artery bypass grafting; PCI: Percutaneous coronary artery intervention. Discussion This study demonstrates, for the first time out of the European continent, that the mortality rate of patients with CICSH is similar to that found in a population without CICSH. Median survival of the 52 CICSH patients was 10.0 years (95% CI: 7.4 – 12.6 years). Cardiovascular mortality and trauma-related mortality, important endpoints in patients with prolonged asystole episodes, were also similar in both cohorts. These results are analogous to that described by Hampton et al. 9 Those authors did not find any association between the presence of CICSH and survival in a cohort of 1,504 English patients with CSH (median age 77 years, 59% female). 9 In that cohort, the median survival of CICSH patients was 8 years (95% CI: 7.3 – 8.7 years). 9 That survival was inferior to the one observed in the 52 CICSH patients described in the present study, but was not different to that found in English elderlies with CSH and pure vasodepressor response (median survival of 7 years; 95% CI: 6.4 – 7.4 years). 9 In the same study, Hampton et al. 9 described that the total mortality, cardiac mortality, stroke and trauma-related mortality of the CSH cohort were not different from that found in sex- and age-matched English patients without CSH. 9 In another European study, the natural history of 262 patients with carotid sinus syncope was described by Brignolle et al. 10 Eighty-nine patients (34%) died after 46 ± 23 months of follow‑up. 10 This high mortality rate was ascribed to the advanced age of the population and to the presence of important comorbidities. 10 Similar finding were published by Sutton et al., 7 and by Claesson et al. 11 Sutton et al. 7 reported a 36%mortality rate during 5 years of follow-up. 7 Claesson et al. 11 surveyed 106 CSH patients (64 with CICSH). After a median follow-up time of 8.6 ± 2.1 years, the mortality rate of the 106 CSH patients was not significantly different from that found in 166 patients without CSH (32% x 22%; p = 0.073). 11 Hence, until now, no one has been able to prove the presence of any independent relation between the presence of CICSH and mortality. All of these studies evaluated residents of the European Continent and, in all of them, the natural history of CICSH patients may have been altered by pacing therapy. 5,7,9,11 In the present study, we have shown that the risk of death was related to population age, to the presence of atherosclerosis and to the presence of risk factors for atherosclerosis. These findings indicate that the presence of CICSH should be interpreted as a risk marker. This hypothesis is supported by our Cox regression results, which showed a relation between the risk of mortality and age at the time of recruitment, and a relation between mortality and the presence of atherosclerosis. Furthermore, the Cox regression results failed to demonstrate any relation between the presence of CICSH and mortality. Patients with a significant fall in blood pressure after CSM are usually managed with general measures that aim to increase their blood volume, including elastic stockings, physical counterpressure maneuvers, discontinuation/ 247