Table 2.

Overview of relevant studies describing HRV measures in patients with AF.

First author	Year	N	Findings
Van den Berg et al. (52)	1997	28	Baseline HRV was higher in AF group. After administration of methylatropine, HRV neared zero in the control group whereas it returned to baseline in AF group. SD, RMSSD, LF and HF at baseline were significantly (p < 0.05) correlated with vagal tone in both groups.
Fioranelli et al. (9)	1999	28	In the 5 min before onset of AF 2 distinct patterns were differentiated based on power spectrum analysis. In half of the episodes there was an increase in sympathetic tone, while the other half had an increase in parasympathetic tone. There was overlap of episodes within subjects.
Akyürek et al. (53)	2003	47	After electrical cardioversion, patients with persistent AF exhibited reduced HRV compared to healthy controls. Patients with AF recurrence had lower HRV compared to those with AF recurrence.
Vikman et al. (54)	2003	78	Increased HF, reflecting enhanced autonomic tone, was associated with AF recurrence after electrical cardioversion of persistent AF. Short-term and non-linear HRV measures were not associated with outcome.
Friedman et al. (55)	2004	38	Reduced HRV correlated with increasing left atrial and left ventricular dimensions. Left atrial dimension was an independent determinant of HRV. HRV greater in “lone AF” than other cardiac disorders.
Lombardi et al. (56)	2004	65	Among 110 paroxysmal AF episodes, approximately 70% were preceded by increase in sympathetic activity while only in 30% a vagal predominance was detected.
Seaborn et al. (57)	2014	83	RF catheter ablation of paroxysmal and persistent AF was associated with reduced HRV. At 1-year follow-up, patients with recurrence had only temporary HRV reduction, while in patients without recurrence the change in HRV was sustained.
Perkiömäki et al. (58)	2014	784	In a middle-aged population, the only HRV predictor in multivariable analysis of new-onset AF was reduced LF.
Vesela et al. (59)	2019	45	There was no difference in change in short-term HRV measures before and after catheter RF ablation when comparing PVI with PVI + GP ablation. Vagal responses during ablation were not different between subgroups.
Marinkovic et al. (60)	2020	100	HRV changes during the 3-month period after RF catheter ablation for paroxysmal AF may predict long-term outcomes. SDNN cut-off value of 62.5 ms showed the best predictive ability for late recurrence AF.
Khan et al. (61)	2021	94	Patients with permanent AF exhibited higher HRV compared to those with paroxysmal AF. However, measurements were obtained in AF.
Kim et al. (62)	2022	782	Higher HRV, assessed by HF, RMSSD, and pNN50, was associated with new-onset AF in patients with hypertension reflecting the importance of increased parasympathetic activity.