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Concept: Premature atrial contraction


Premature cardiac contractions are associated with increased morbidity and mortality. Though experts associate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) with caffeine, there are no data to support this relationship in the general population. As certain caffeinated products may have cardiovascular benefits, recommendations against them may be detrimental.

Concepts: Cardiac electrophysiology, Premature ventricular contraction, Premature atrial contraction


Recent data suggests that high burden of premature atrial complexes after pulmonary vein isolation predicts recurrences of atrial arrhythmias. The present study sought to assess the role of premature atrial complexes burden in predicting atrial arrhythmias recurrences in patients with atrial fibrillation (AF) who have undergone second-generation cryoballoon ablation (CB-Adv).

Concepts: Present, Time, Blood, Heart, Atrial fibrillation, Future, Cardiac electrophysiology, Premature atrial contraction


Atrial fibrillation and heart failure are 2 of the most common diseases, yet ready means to identify individuals at risk are lacking. The 12-lead ECG is one of the most accessible tests in medicine. Our objective was to determine whether a premature atrial contraction observed on a standard 12-lead ECG would predict atrial fibrillation and mortality and whether a premature ventricular contraction would predict heart failure and mortality.

Concepts: Disease, Cardiology, Heart, Atrial fibrillation, Cardiac electrophysiology, Ventricular fibrillation, Premature ventricular contraction, Premature atrial contraction


The prognostic significance of premature atrial complex (PAC) burden is not fully elucidated. We aimed to investigate the relationship between the burden of PACs and long-term outcome.

Concepts: Complex, Complexity, Thought experiment, Premature atrial contraction, Political action committee


Atrial fibrillation (AF) prediction models have unclear clinical utility given the absence of AF prevention therapies and the immutability of many risk factors. Premature atrial contractions (PACs) play a critical role in AF pathogenesis and may be modifiable.

Concepts: Cohort study, Epidemiology, Clinical trial, Atrial fibrillation, Cardiac electrophysiology, Learning, Premature atrial contraction


We aimed to explore electrophysiological characteristics of premature atrial contractions (PACs) originating from pulmonary veins (PVs) and non-PVs and to evaluate the effectiveness and safety of catheter ablation for PACs.

Concepts: Blood, Heart, Cardiac electrophysiology, Premature atrial contraction


Frequent premature atrial complexes (PACs) are universal in the general population; however, their clinical significance is unclear. We hypothesize that frequent PACs are associated with increased risk of stroke and death. The PubMed (from 1966 to April 2017) and Embase (from 1974 to April 2017) databases were searched for longitudinal studies that reported the relation of PACs with incidence of stroke and death with various etiologies. Study quality was evaluated, and the relative risks (RR) of unfavorable outcomes in subjects with frequent PACs vs those without were calculated. Eleven studies with overall high quality were eligible according to inclusion criteria. The meta-analysis demonstrated that frequent PACs were associated with an increased risk of stroke (unadjusted RR: 2.20, 95% confidence interval [CI]: 1.79-2.70; adjusted RR: 1.41, 95% CI: 1.25-1.60) and death from all causes (unadjusted RR: 2.17, 95% CI: 1.80-2.63; adjusted RR: 1.26, 95% CI: 1.13-1.41), cardiovascular diseases (unadjusted RR: 2.89, 95% CI: 2.20-3.79; adjusted RR: 1.38, 95% CI: 1.24-1.54), and coronary artery disease (unadjusted RR: 2.74, 95% CI: 1.64-4.58; adjusted RR: 1.74, 95% CI: 1.27-2.37). No significant publication bias was detected. The association was robust in sensitivity analysis, subgroup analysis, and pooled analysis of estimates adjusting for confounding factors. Frequent PACs are not benign phenomena; they are associated with higher risk of unfavorable outcomes. Further research on the optimal management of subjects with frequent PACs is urgently required.

Concepts: Epidemiology, Myocardial infarction, Atherosclerosis, Coronary artery disease, Heart, Evidence-based medicine, Meta-analysis, Premature atrial contraction


Premature atrial complexes (PACs) have been proposed as a possible mediator between normal sinus rhythm and atrial fibrillation (AF). The aim of this study was to summarize the available knowledge of association between PACs and recurrent stroke or transient ischemic attack (TIA) in ischemic stroke patients. Areas covered: In this systematic review, we investigated the risk of recurrent events in patients who experienced ischemic stroke or TIA. Occurrence of PACs in electrocardiographic monitoring after index stroke/TIA was required. We identified and included three observational cohort studies, investigating in total 1005 patients. The studies reported that a significant burden of PACs occurred in a high proportion of stroke and TIA patients. More PACs were independently associated with an increased risk of recurrent stroke or TIA or the composite of recurrent stroke/TIA or death. Definition of PACs cut-off as well as patient characteristics differed between groups. Expert Commentary: This review supports an association between higher burden of PACs and recurrent stroke, and stresses the need for studies on PACs in stroke patients. A special awareness of stroke patients with a high PACs load is recommendable particularly for assessing the intensity and duration toward AF progression, and possible future treatment recommendations.

Concepts: Myocardial infarction, Heart, Stroke, Atrial fibrillation, Transient ischemic attack, Cardiac electrophysiology, Atrial flutter, Premature atrial contraction


Foetal premature atrial contractions (PACs) are the most commonly encountered and also the most benign foetal arrhythmia. A retrospective cohort study was conducted with the objective to assess whether the presence of foetal breathing was associated with the presence of foetal PACs. A further objective was to evaluate whether this association would affect neonatal outcomes at a high volume referral centre. The diagnosis of PACs was based on the observation of a premature atrial contraction followed by a ventricular contraction on ultrasound myocardial M-mode. Trained ultrasonographers documented in the ultrasound report whether or not foetal breathing was present with PACs. 91 exams were identified, which included 75 individual pregnancies. Six women were identified who had foetal PACs associated with foetal breathing on ultrasound evaluation. Foetuses with PACs did not differ between the associated breathing and no-associated breathing groups with respect to maternal age, parity, mode of delivery, gestational age at delivery or birthweight. This study reaffirms that isolated PACs are a benign finding. Furthermore, it adds to the pool of literature on foetal PACs in that it is not associated with abnormal pregnancy outcomes regardless of the presence or absence of foetal breathing. Impact statement • What is already known on this subjectSince foetal breathing can effect Doppler ultrasound assessment of the foetal cardiovascular system, it is reasonable to consider that it may impact conditions such as foetal arrhythmias. • What the results of this study addFoetal breathing does not impact on the presence of premature atrial contractions. • What the implications are of these findings for clinical practice and/or further researchFoetal breathing is not associated with the finding of foetal premature atrial contractions.

Concepts: Cohort study, Pregnancy, Embryo, Fetus, Obstetrics, Cardiac electrophysiology, Premature ventricular contraction, Premature atrial contraction


The purpose of this study was to characterize the repeatability of ectopic beats, defined by premature atrial contractions (PACs) and premature ventricular contractions (PVCs), on ambulatory electrocardiogram (aECG) monitoring and evaluate the effect of length of aECG monitoring on the repeatability estimates.

Concepts: Myocardial infarction, Cardiology, Cardiac electrophysiology, Ventricular fibrillation, Electrocardiography, Premature ventricular contraction, Premature atrial contraction, Heart rate turbulence