Cardioinhibitory carotid sinus hypersensitivity: prevalence and predictors in 502 outpatients.
BACKGROUND
Cardioinhibitory response (CIR) is defined as asystole >3 seconds in response to 5-10 seconds of carotid sinus massage (CSM). Pacemaker implantation is indicated for patients with unexplained syncope episodes and CIR.


OBJECTIVE
To determine the prevalence and predictors of CIR in patients with a high prevalence of cardiovascular disease, and assess the clinical significance of CIR in patients with a history of unexplained syncope or falls.


METHODS
Cross-section design study. Outpatients, aged > or =50 years, referred to the electrocardiography sector of a tertiary hospital. Those with dementia, carotid bruit, and history of myocardial infarction, stroke or transient ischemic attack in the preceding 3 months were excluded. CSM was performed by a single investigator, with the patients in the supine position. CSM was applied on the right side and then on the left side during 10 seconds each time.


RESULTS
502 patients underwent CSM. CIR was present in 52 patients (10.4%; 95% CI: 7.7%-13%). Independent predictors of CIR were male gender (OR: 2.61%; CI 95%: 1.3%-5.1%), structural heart disease (OR: 3.28%; CI 95%: 1.3%-7.9%) and baseline heart rate (P<0.05). The sensitivity of the CIR to CSM in syncope evaluation was low (9.8%). Specificity was high (89.5%), being even better in women (95.3%) and in those without structural heart disease (96.2%).


CONCLUSIONS
CIR was detected in 10.4% of the patients aged > or = 50 years. In males and in patients with structural heart disease CIR was more common. In women and patients with no apparent structural heart disease, the presence of CIR was a highly specific finding in the evaluation of syncope or falls.
Lacerda
Gustavo de Castro
Gde C
Universidade Federal do Rio de Janeiro- Hospital Geral de Bonsucesso - Rio de Janeiro, RJ - Brazil. glacerda@cardiol.br
Pedrosa
Roberto Coury
RC
Lacerda
Renato Côrtes de
RC
Santos
Marcela Cedenilla dos
MC
Perez
Maurício de Andrade
Mde A
Teixeira
Alfredo Brasil
AB
Siqueira-Filho
Aristarco Gonçalves de
AG
D000058:Accidental Falls / Q000706:statistics & numerical data; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D002340:Carotid Artery Diseases / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D002346:Carotid Sinus / Q000503:physiopathology*; D004812:Epidemiologic Methods; D005260:Female; D006323:Heart Arrest / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D017678:Sex Distribution; D016683:Supine Position; D013575:Syncope / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology