Frequent premature atrial contractions are associated with atrial fibrillation, brain ischaemia, and mortality: a systematic review and meta-analysis

Premature atrial contractions (PACs) are a common cardiac phenomenon, traditionally considered to be of little clinical significance. Recent studies, however, suggest that PACs are associated with atrial fibrillation (AF), as well as ischaemic stroke, transient ischaemic attack, and mortality. This systematic review aims to investigate the association between PACs on standard electrocardiogram (ECG) as well as PAC-count on Holter monitor and future detection of AF, brain ischaemia, and all-cause mortality in patients without a history of AF. We searched PubMed, Embase (OVID), and Cochrane Database of Systematic Reviews from inception through 11 April 2018 and performed a systematic review and meta-analysis. We assessed risk of bias using a modified Quality In Prognosis Studies tool. The primary expression of associations in meta-analysis was the unadjusted hazard ratio (HR) using a random effects model. We identified 33 eligible studies including 198 876 patients from Western and East Asian populations with mean age ranging 52–76 years. Frequent PACs on 24–48 h Holter was associated with AF [HR 2.96, 95% confidence interval (CI) 2.33–3.76; 15 cohorts, n = 16 613], first stroke (HR 2.54, 95% CI 1.68–3.83; 3 cohorts, n = 1468), and all-cause mortality (HR 2.14, 95% CI 1.94–2.37; 6 cohorts, n = 7571). There was insufficient evidence to conclude that presence of ≥1 PAC on standard 12-lead ECG is associated with future AF detection. In older patients without a history of AF, frequent PACs on 24–48 h Holter are significantly associated with AF, first stroke, and mortality.