Comparison of left atrial electrophysiologic abnormalities during sinus rhythm in patients with different type of atrial fibrillation

The purpose of this study is to explore the left atrium (LA) electrophysiologic abnormalities in atrial fibrillation (AF) patients detected during sinus rhythm and to determine the relationship between the type of AF and the electrophysiologic substrate in the LA. Eighty patients with AF (30 paroxysmal AF, 22 persistent AF, and 28 long-standing AF) and 20 age- and sex-matched patients with left-sided accessory pathway were prospectively studied. High-density three-dimensional electroanatomic mapping was performed during sinus rhythm in LA, which was divided into six segments for regional analysis. Mean bipolar voltage, low voltage zone (LVZ) distribution, LA activation time, and electrogram complexity were assessed. The LA mean voltage was 3.67 ± 0.68 mV in no AF group, 2.16 ± 0.63 mV in the paroxysmal, 1.81 ± 0.36 mV in the persistent, and 1.48 ± 0.34 mV in the long-standing AF patients (P < 0.001). The total LA activation time was 75.3 ± 5.4 ms in no AF, 89.7 ± 12.3 ms in paroxysmal AF, 104.9 ± 6.1 ms in persistent AF, and 115.6 ± 12.1 ms in the long-standing AF patients, respectively (P < 0.001). With the progression of AF, there was a higher incidence of LVZ detection and increased prevalence of complex electrograms with 95 % of complex electrograms in areas with the bipolar voltage ≤ 1.3 mV in persistent and long-standing AF patients. Patients with AF have abnormal electrophysiologic substrate in sinus rhythm characterized by lower mean bipolar voltage, more prevalent complex electrograms, and longer LA activation time. This substrate progresses parallel to progression of AF type.