Reduced baroreflex sensitivity in patients with vasovagal syncope

Abstract

OBJECTIVES: The evidence is confl icting regarding the role of barorefl ex in patients with vasovagal syncope. The aim of the study was to measure barorefl ex sensitivity (BRS) and hemodynamic parameters during head up tilt test (HUT) with nitroglycerine stimulation. METHODS: Nitroglycerine stimulated HUT was performed in 51 patients with the history of recurrent syncope (mean age 46± 19 years, 18 men, 23 women). Cardiac output (CO), stroke volume (SV), left-ventricular ejection time (LVET) and total peripheral resistance (TPR) were assessed during HUT by volume-clamp method using a beat-to-beat photopletysmography. Spontaneous BRS sensitivity was computed using a sequential BRS calculation. RESULTS: HUT was positive after nitroglycerine administration in 28 patients and negative in 23 patients. BRS was lower at the time of syncope in HUT positive group compared to end-test values in HUT negative group (0.54±0.27 vs 0.72±0.35, p = 0. 03). At the time of syncope, CO was signifi cantly lower in HUT positive patients compared to HUT negative patients (2.6±1.4 vs 4.3±1.4 l/min, p < 0.0001), similarly as SV (34.7±14.7 vs 49.2±19 ml, p=0.005 ). LVET was signifi cantly higher in syncopal patients (282.27±26.2 vs 240.5±58.8 ms, p=0.002) and TPR did not differ between two groups. CONCLUSIONS: Reduced BRS may contribute to the development of the vasovagal syncope by inability to adequately counteract hypotension resulting from decreased cardiac output at the time of syncope (Tab. 3, Ref. 18). Text in PDF www.elis.sk.

Improvement in low upright baroreflex sensitivity is associated with positive clinical effect of orthostatic training

“…Abnormally functioning baroreflex at the onset of vasovagal reaction can contribute to hypotension. In our previous study, we observed decreased BRS at the time of nitroglycerine‐induced syncope and the similar observations were made also by others …”

Hemodynamic Response to the Head-Up Tilt Test in Patients With Syncope as a Predictor of the Test Outcome: A Meta-Analysis Approach

“…Therefore, different studies in the analysis for the separate signals were performed. The data for all the signals were included just in two papers (Shen et al, 2000) (Mitro et al, 2015). The data for HR, sBP and dBP were found in four papers (Furlan et al, 1998; Shen et al, 2000; Kim et al, 2015; Mitro et al, 2015).…”

“…During the study we conducted a systematic review of research and performed meta-analysis to explore the possibility of HUTT test result prediction based on the parameters measured in the supine position and after tilt. We systematically reviewed the papers containing data from the tilt test measured in two groups of patients suffering from syncope (Catherine et al, 1997; Furlan et al, 1998; Shen et al, 2000; Fucà et al, 2006; Verheyden et al, 2008; Nigro et al, 2012; Tanriverdi Yilmaz et al, 2013; Koźluk et al, 2014; Freitas et al, 2015; Kim et al, 2015; Mitro et al, 2015; Russo et al, 2015; Sucu et al, 2015). The first group consisted of patients with the positive HUTT test result (HUTT(+)) and the second with the negative one (HUTT(–)).…”

Baroreceptor activity and sensitivity: normal values in children and young adults using the head up tilt test

“…As baroreceptor dysfunction has been implicated in multiple disease processes, understanding the exact mechanism and normal functioning parameters of the baroreceptors will be an important tool to improve diagnosis and monitor therapies. 27 The few studies in the pediatric population that have been published to date do not provide a standardized investigation regarding the changes in baroreceptor activity under the stress of the HUTT. 4,17,20 The studies thus far also included patient populations with underlying disease processes that could possibly skew the values obtained, making it difficult to generalize the results to the normal population.…”