SPC365

Autonomic dysfunction is diverse in reflex syncope and atrial fibrillation

Session: Posters (Sessão 1 - Écran 2) - Arritmias 1 - Fibrilhação Auricular 1
Speaker: Mónica Ferreira

Congress: CPC 2022
Topic: C. Arrhythmias and Device Therapy
Theme: 05. Atrial Fibrillation
Subtheme: 05.1 Atrial Fibrillation - Pathophysiology and Mechanisms
Session Type: Pósters Electrónicos
FP Number: ---
Authors: Mónica Ferreira; Sérgio Laranjo; Pedro Cunha; Helena Fonseca; Mário Oliveira; Isabel Rocha
<p><span style="font-size:12pt"><span style="font-family:&quot;Times New Roman&quot;,serif"><strong><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">Introduction</span></span></span></strong><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">:&nbsp;</span></span></span><span style="font-size:11.0pt"><span style="background-color:white"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:black">Syncope and atrial fibrillation (AF) are both common entities and frequently occur together in an acute clinical scenario</span></span></span></span><span style="font-size:11.0pt"><span style="background-color:white"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">.&nbsp;</span></span></span></span><span style="font-size:11.0pt"><span style="background-color:white"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:black">Both are multifactorial in etiology.</span></span></span></span><span style="font-size:11.0pt"><span style="background-color:white"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">&nbsp;<span style="color:inherit">The autonomic nervous system (ANS) modulates the pathophysiology of both reflex syncope (Rs) and paroxysmal AF (PAF). The level of functional autonomic deficit related to each condition has implications on therapeutic decisions and is influenced by the corresponding degree of autonomic dysfunction&nbsp; which is still a matter of debate.&nbsp; Thus, in the present study, we intend to analyze the autonomic modulation and sensitivity and efficacy of arterial baroreflex during the passive orthostatism test (HUT) in patients with RS and PAF</span></span></span></span></span><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">.</span></span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="background-color:white"><span style="font-family:&quot;Times New Roman&quot;,serif"><strong><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">Methods and Results:</span></span></span></strong><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e"> 20 subjects with PAF were compared with 20 patients with RS and 20 healthy subjects. Each subject was submitted to HUT. The systolic blood pressure (SBP) peaks and the R-R intervals were analysed in 4 intervals: 2 minutes in the supine position; first 2 minutes of orthostatism (TA1); next 2 minutes (TA2); 2 minutes of rest. Significant differences were identified in both the blood pressure and chronotropic profiles of the different groups during HUT. As for the SNA activity patterns, PAF and Rs presented a globally decreased heart rate variability when compared with the control group. Three different profiles could be found: a progressive increase in sympathetic activity and a decrease in parasympathetic activity during TA1 were observed in the control group. In the FAP group, the increase of sympathetic activity was blunted in TA1, being delayed to TA2 where a significant increase was seen, with no changes in parasympathetic activity. In the Rs group an initial significant increase in sympathetic activity was seen, followed by a progressive decrease. In the baroreflex response there was a progressive and significant increase in the number of ramps/min in the control group, which wasn&rsquo;t replicated in the Rs and FAP groups. The sensitivity of the baroreflex was similar between the groups in the basal period, with a significant decrease after orthostatism, values being significantly lower in the PAF and Rs groups. The baroreflex efficacy index was significantly lower in the Rs and PAF group in all periods analysed, when compared with the control group. </span></span></span></span></span></span></p>

<p><strong><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e">Discussion:</span></span></span></strong><span style="font-size:11.0pt"><span style="font-family:&quot;Calibri&quot;,sans-serif"><span style="color:#201f1e"> There are different patterns of hemodynamic, autonomic response and baroreflex adaptability between the three groups These results seem to translate some degree of diverse autonomic impairment in FAP and Rs.</span></span></span></p>