Abstract Body (Do not enter title and authors here): Background: Knowledge of physiologic and anatomic abnormalities that attend the spectrum of atrial fibrillation (AF) is incomplete. Left atrial physiology in patients who have developed atrial fibrillation and have converted to sinus rhythm may be a productive focus for exploration.
Hypothesis: We hypothesize that left atrial function is altered in patients with a history of paroxysmal AF despite conversion to sinus rhythm and may precede development of AF.
Methods: 33 patients with paroxysmal atrial fibrillation (pAF group) and 40 healthy age matched patients (control group) underwent echocardiography while in sinus rhythm. 28 patients with risk factors for AF (risk group) were compared to control.
Results: Table 1 shows baseline characteristics of age matched control and pAF groups, with mean age of 60 and 62. Of the pAF group, 58% had a history of hypertension and trended towards obesity (Table 1, p<0.001). Left atrial end systolic volume index (LAESVI) and left atrial end diastolic volume index (LAEDVI) was increased in pAF (36 and 19) compared to controls (28 and 11) (Table 2, p<0.001). Emptying fraction was diminished in pAF group when compared to controls with 46% and 59% (Figure 3, p<0.001). LA global longitudinal strain is diminished in pAF at -29% compared to controls at -33% (Table 2, p=0.014). Emptying fraction was diminished in risk group at 53% compared to control group 59% (Figure 1, p=0.007).
Conclusion: The left atrium remains significantly altered in both its physiology and anatomy in atrial fibrillation despite conversion to sinus rhythm, LA volumes are increased throughout the cardiac cycle and LA contractile performance (strain) is reduced. Left atrial abnormalities precede development of AF in risk group.