RT Journal Article
SR Electronic
T1 Autonomic dysregulation; a mechanism of asthma death
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P2139
VO 44
IS Suppl 58
A1 Jaymin Morjaria
A1 Tim Rowland
A1 Puneet Tailor
A1 Shaan Hyder
A1 Caroline Wright
A1 Simon Hart
A1 Alyn Morice
YR 2014
UL http://erj.ersjournals.com/content/44/Suppl_58/P2139.abstract
AB BackgroundEpidemiological evidence and post-mortem case series suggest a variety of pathophysiological mechanisms underlying mortality in asthma. In some asthmatics sudden death is not preceded by obvious worsening of asthma symptoms.AimWe hypothesize that this group may be susceptible to fatal cardiac arrhythmias due to a dysregulation of autonomic function.MethodsWe investigated autonomic function in 2 groups of asthmatics; those with a history of syncope during exacerbations (n=4) and those without (n=10). These were compared with non-asthmatic controls (n=10). The simulated diving reflex was chosen as it has known reproducible effects on cardiovascular autonomic function. Measurements obtained included heart rate, blood pressure and electrocardiograph monitoring preceding and throughout the simulated dive.ResultsNormal subjects as well as non-syncopal asthmatics responded in a typical fashion to a simulated dive with initial tachycardia followed by bradycardia (between group difference -1.42bpm, p=NS). Compared to controls, syncopal asthmatics demonstrated an attenuated tachycardic response (-14.32bpm, p=0.03). Dive-induced AUC of change in heart rate was significantly different in syncopal asthmatics compared to controls (p=0.04), demonstrating a marked bradycardia. QTc interval estimation produced similar significant changes. No between group blood pressure differences were noted.ConclusionWe demonstrate a relative bradycardic response to a simulated diving reflex in syncopal asthmatics suggesting an autonomic dysfunction, which may predispose to asystolic cardiac arrest. This mode of death in acute asthma is supported by case reports and epidemiological findings but has previously been unrecognized as a mechanism.