IMPROVEMENT IN LEFT-VENTRICULAR FUNCTION BY ABLATION OF ATRIOVENTRICULAR NODAL CONDUCTION IN SELECTED PATIENTS WITH LONE ATRIAL-FIBRILLATION

Left ventricular (LV) function was studied in 30 patients with lone at rial fibrillation (AF) (paroxysmal [n = 27] and persistent [n = 3]) be fore and after ablation of atrioventricular conduction. In all patient s, drug treatment did not control ventricular rate during AF or preven t recurrences of the arrhythmia, or both. LV ejection fraction, and LV end-systolic and end-diastolic, and left atrial dimensions were measu red by echocardiography before (mean 7 +/- 10 months, range < 1 to 37) and after (14 +/- 20 months, < 1 to 77) ablation. Before ablation, LV ejection fraction was less-than-or-equal-to 50% in 12 patients (group I) and > 50% in 18 (group II). After ablation, LV ejection fraction i ncreased significantly in group I from 43 +/- 8% to 54 +/- 7% (p < 0.0 001). There were also significant decreases in LV-end systolic and end -diastolic, and left atrial dimensions. No changes in these parameters were observed in group II. Groups I and II had a significant differen ce in the duration of AF (group I: mean II years, range 8 to 28; and g roup II: 5 years, 2 to 14) (p < 0.05). No difference was present in ag e, sex, New York Heart Association functional class for dyspnea, or ty pe of ablation procedure. Thus, some patients with lone AF may show de terioration of LV function, which appears to be related to the duratio n of the arrhythmia; in these cases, LV function may improve significa ntly after ventricular rate control is accomplished by ablation of atr ioventricular conduction.