| BackgroundThe ventricular response in atrial fibrillation (AF) is determined by disorganized atrial impulses and consequently unpredictable atrioventricular (AV) conduction. It has a characteristic nature of being "irregularly irregular". However, processing numeric heart beats could unveil certain hidden patterns in the ventricular rhythms of AF. Based on the data acquired from24-hour electrocardiogram monitor (Holter monitor), the3-dimension Poincare plot could both recognize and quantify ventricular rate clustering.ObjectivesTo determine the analysis method of ventricular rate clustering and investigate its mechanism and clinical significance in patients with persistent atrial fibrillation. And also, to compare ventricular clustering with other analysis methods for ventricular response in atrial fibrillation.MethodsThe study group included50patients with persistent atrial fibrillation, with44patients with non-valvular atrial fibrillation, and6with valvular atrial fibrillation. Their clinical profiles were collected. The ventricular rate clustering was analyzed and compared with heart rate variability and RR interval peak distribution. Seven randomly selected patients with atrial flutter were also analyzed for ventricular clustering, heart rate variability and RR interval peak distribution, and compared with atrial fibrillation group.ResultsIn the non-valvular atrial fibrillation patients, the anterior-posterior diameter of left atrium (LAD) was significantly smaller in patients with clustered ventricular rate. Compared to non-valvular atrial fibrillation patients, valvular atrial fibrillation patients had significantly larger LAD, but similar ventricular clustering and clustering index. All patients with atrial flutter had high degree of ventricular rate clustering, with a significantly higher clustering index than patients with non-valvular atrial fibrillationConclusion1. Ventricular rate clustering directly reflected the degree of atrial signal organization in patients with atrial fibrillation. Its formation might be related to the nature of atrial reentrant circuits.2. Valvular atrial fibrillation patients had larger atrium but similar ventricular rate clustering compared to non-valvular atrial fibrillation, thus inferring a different atrium substrate nature in valvular atrial fibrillation.3. In non-valvular atrial fibrillation, patients with ventricular rate clustering had smaller left atrium.4. Ventricular rate clustering might become a potent prognosis predictor for catheter ablation in persistent atrial fibrillation. |
