Supraventricular prematurity and prevalence as a marker of atrial fibrillation

Background

Supraventricular ectopics beats (SVEC) and short supraventricular tachycardias (sSVTs) are commonly found in asymptomatic individuals and are commonly considered benign. Recent studies suggest SVEC and sSVTs are more commonly found in individuals at higher risk of atrial fibrillation (AF) and in the electrophysiology lab more premature beats commonly initiate arrhythmias. The association between the type, amount and the level of prematurity of SVECs and AF remains uncertain.

Purpose

This study aimed to determine how the type and prematurity level of SVEC and SVTs correlate with the development of AF over time.

Methods

Single lead ECG data was obtained from STROKESTOP I, a large prospective AF screening study involving 28 768 individuals aged 75/76-year-old. Among the participants invited to screening, 7 165 participants took part. The participants were asked to perform 30-second intermittent ECGs twice daily for two weeks using a handheld single lead ECG device. The participants were then followed up using registry data for a total of eight years.

The ECG data were analysed regarding beat detection and interval measurements, SVEC (and couplet, triplets and quadruplets of SVECs, as well as sSVTs. A SVEC was defined as a beat with an R-R interval shorter than 13%, with shorter intervals indicating more premature ectopy.

Results

In total, 6145 participants were included who did not have AF at the time of screening and for whom clinical data were available. Among these, 772 patients (12.6%) developed AF over 8 years. Single SVECs occurred in 52.24% in non-AF patients compared to 71.5% of AF patients. Single SVECs significantly increased the risk for AF after adjusting for other arrhythmias and clinical risk factors with a HR of 1.91 (1.24-2.94), p <0.005. Patients with SVECs with a shorter coupling interval, that is more premature beats, had a higher risk of developing AF (Table 1) compared to those with less premature SVEC. Double, triple and tetra SVECs showed a small increased risk for AF HR 1.29 (1.04-1.6), p=0.02, but more premature runs of SVECs increased the risk of AF. sSVT also significantly increased the risk of AF HR 2.51 (1.73-3.65), p <0.005 and patients with sSVTs were diagnosed with AF after a mean of 2.83 (2.11-4.83) years.

Conclusion

In this large, population-based cohort of older adults, SVECs and sSVTs were common and independently associated with a higher risk of future AF. Single SVECs nearly doubled the risk of AF, while sSVTs increased it further, with AF occurring after a shorter follow-up time. These results highlight prematurity, defined by the coupling interval, as an important marker of arrhythmia susceptibility.