![]() Patients with AF were stable on rate control and antithrombotic medication. We recruited 2 groups of patients: those with AF (and hypertension) (n = 61) and hypertensive controls (n = 33). The patients recruited were representative of the typical patients seen in outpatient clinics. No participants were excluded from the study after initial screening. 18Ī total of 94 participants were recruited from the AF and hypertension services at Sandwell and West Birmingham Hospitals NHS Trust between October 2018 and March 2019. Reporting of the study conforms to broad EQUATOR guidelines. Anonymised data and materials have been made publicly available at the Harvard Dataverse and can be accessed at. ![]() The study was approved by the Health Research Authority (HRA) and National Research and Ethics Service (NREC) Committee London-Camden & Kings Cross (18/LO/1064). Participants were provided with detailed information sheets, and written informed consent was obtained from all participants, in accordance with the Declaration of Helsinki (2013). 2 METHODS 2.1 ParticipantsĮligible participants underwent screening against inclusion and exclusion criteria before being invited to take part in the study (see Supplementary Material). 13 Given these findings, and the high propensity of AF and hypertension to co-exist, we hypothesised that HRV will be worsened in patients with AF and hypertension, compared to hypertension alone, and that optimisation of AF and BP therapy would improve HRV. However, using selective pharmacological blockade of cardiac sympathetic and parasympathetic activity, van den Berg and colleagues determined that HRV is related to vagal tone in AF patients when not in sinus rhythm. 17 Even then these studies examined HRV in AF patients while they were in sinus rhythm at the time of the study. 16 Conversely, Freedman and colleagues found HRV to be greater in lone AF than other cardiac disorders. 13- 15īarauskiene et al have shown that HRV is significantly lower in AF patients compared to controls. 9- 12 However, there have been limited reports examining HRV in AF. HRV has been studied extensively in patients with normal sinus rhythm and shown to have important prognostic implications for various cardiovascular disorders including hypertension. 6- 8 Exploring cardiac ANS is possible through heart rate variability (HRV) evaluation. Studies have reported that both sympathetic and parasympathetic branches of the cardiac ANS are involved in the pathophysiology of AF. ![]() Additionally, cardiac ANS activation might also determine the presence and severity of AF-related episodes, such as dizziness, presyncope or syncope secondary to impaired baroreflex or carotid sinus sensitivity. 3 As such, the cardiac ANS plays a central pathophysiological role in the initiation and progression of AF. In majority of patients with AF, reflex excitation of cardiac myocytes due to AF itself together with involvement of concomitant risk factors such as hypertension, obesity and obstructive sleep apnoea influence cardiac ANS activity. 3 This includes direct electrophysiological effects leading to alterations in atrial structure. 2 The cardiac ANS has a significant role in the atrial environment, predisposing to the substrate, perpetuators and triggers for AF. 1 There is increasing evidence that abnormalities of the cardiac autonomic nervous system (ANS) are involved in the pathogenesis of AF. ![]() ![]() Modulation of autonomic influence on cardiovascular system should be explored in future studies.Ītrial fibrillation (AF) is widely recognised as a significant cardiovascular condition associated with poor outcomes. HRV is higher in permanent AF compared to paroxysmal AF suggesting evident autonomic influence in the pathophysiology of permanent AF. ConclusionsĪF, independent of hypertension, is characterised with marked HRV and is possibly related to vagal tone. Optimisation of heart rate and BP had no significant impact on HRV in permanent AF. Permanent AF was an independent predictor of HRV on multivariable analysis ( P = .006). Time-domain and nonlinear indices of HRV were higher in permanent AF group compared to paroxysmal AF ( P ≤ .001). Time-domain and nonlinear indices of HRV were higher in AF (and hypertension) group compared to hypertensive controls ( P ≤ .01). Permanent AF group (n = 30) was followed up after 8 weeks following optimisation of their heart rate and blood pressure (BP). Time-domain, frequency-domain and nonlinear measures of HRV were determined. The AF (and hypertension) group was subdivided into permanent AF (n = 30) and paroxysmal AF (n = 31) and re-studied. We studied HRV in AF (and hypertension) (n = 61) and hypertension control group (n = 33). As these conditions frequently co-exist, we sought to determine whether AF would worsen HRV in hypertensive patients. Atrial fibrillation (AF) and hypertension are independently associated with impaired autonomic function determined using heart rate variability (HRV). ![]()
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