Table 1.

Summary of studies investigating the association between AHREs and stroke risk

Trial	Study type and duration	Study population	Criteria for the diagnosis of AHRE	Outcomes
MOST29	Subgroup analysis of RCT, 6 years	n = 312, median age 74 years, 55% female, and 60% had a history of SND	Atrial rate >220 bpm for 10 consecutive beats	Compared with control, AHREs were associated with increased total mortality (HR 2.48 95% CI 1.25–4.91, P = 0.0092), death or non-fatal stroke (HR 2.79; 95% CI 1.51–5.15, P = 0.0011), and AF (HR 5.93; 95% CI 2.88–12.2, P = 0.0001)
TRENDS30	Prospective observational study, mean follow-up 1.4 years	n = 2486 with ≥ 1 risk factor for stroke	AT/AF burden = longest total AT/AF duration on any given day during the prior 30-day period and classified as subsets: zero, low (<5.5 h [median duration]), and high (≥ 5.5 h)	Compared with zero burden, AF burden was associated with increased TE: HR 0.98; 95% CI 0.34–2.82, P = 0.97) and 2.20; 95% CI 0.96–5.05, P = 0.06), for low and high, respectively
ASSERT31	Prospective observational study, mean follow-up 2.5 years	n = 2580, age ≥ 65 years, with hypertension and no history of AF	Atrial rate >190 bpm for >6 min	By 3 months, AHREs occurred in 10.1%. AHREs were associated with an increased risk of clinical AF (HR 5.56; 95% CI 3.78–8.17; P < 0.001) and of ischaemic stroke or SE (HR 2.49; 95% CI 1.28–4.85; P = 0.007). After adjustment for predictors of stroke AHREs remained associated with stroke/SE (HR 2.50; 95% CI 1.28–4.89; P = 0.008)
Carelink/VA34	Case crossover study, analysis of data 30 days preceding a stroke	n = 9850, median age 68 years, 99% male, and 98% had a defibrillator	≥5.5 h of AF on ≥1 day in the preceding 30 days	AHREs was associated with a four-fold increased risk of stroke within 30 days (OR = 4.33. 95% CI 1.19–23.7) Risk was highest in the 5–10 days after AHRE and rapidly declined after 10 days
Belgrade Atrial Fibrillation Study35	Single-centre registry study and mean follow-up 9.9 ± 6.1 years	n = 1100, mean age 52.7 ± 12.2 years, 13.3%) had asymptomatic AF	Asymptomatic presentation of first diagnosed AF	Ischaemic stroke risk (log-rank test = 6.2, P = 0.013) was significantly worse for patients with asymptomatic AF compared with those with symptomatic AF
SOS AF project36	Pooled analysis of individual patient data from five prospective studies	n = 10 016, median age 70 years. Pts without permanent AF with ICDs were included if they had at least 3 months of follow-up	Device-detected AF. Cutoff points of AF burden defined as: 5 min, 1, 6, 12, and 23 h	AF burden 1 h was associated with the risk of ischaemic stroke (HR 2.11, 95% CI 1.22–3.64, P= 0.008)

AF, atrial fibrillation; AHRE, atrial high-rate event; AT, atrial tachycardia; bpm, beats per minute; RCT, randomized controlled trial; SE, systemic embolism; SND, sinus node; TE, thromboembolic event.