In this retrospective observational study, we observed 32 patients with paroxysmal or persistent atrial fibrillation (AF) who had impaired LV function without structural heart disease and who underwent catheter ablation. We defined impaired LV function as LV ejection fraction (LVEF) <50%. After ablation, the LVEF became <60% (Group 1; n = 11) or 60% (Group 2; n = 21). We compared the differences in baseline characteristics between the two groups. The patients in Group1 had no ischemic disease. A receiver operating curve (ROC) with area under the curve (AUC) was used to evaluate the prediction efficiency.
Results
There were significant differences in left atrial (LA) volume (LAV) and LAV adjusted by body surface area (LAVI) measured by computed tomography (CT) (p < 0.05 for both). The AUCs were 0.810 and 0.823, respectively. The points at which sensitivity and specificity were maximum were 147 ml and 79. Small LAV and LAVI were predictors of LVEF improvement.
Conclusion
Small LAV measured by CT before ablation may be useful for diagnosis of TCM with AF.
Key words: Tachycardia-induced cardiomyopathy, Arrhythmia-induced cardiomyopathy, atrial fibrillation, catheter ablation, heart failure
1 Introduction
Tachycardia-induced cardiomyopathy (TCM) is a reversible cause of heart failure with impaired left ventricle (LV) function. Atrial fibrillation (AF) is the most common cause.1 We cannot always observe echocardiographic data in typical TCM at the first occurrence: LV ejection fraction (LVEF) is <30%, LV end-diastolic diameter is <65 mm, and LV end-systolic diameter is <50 mm. The diagnosis is determined by a recovery of LV function within 3 months after treatment or control of the arrhythmia.2 In other words, we cannot determine the diagnosis for at least 3 months after arrhythmia control. Moreover, the diagnosis is determined by excluding other causes of cardiomyopathy, especially idiopathic dilated cardiomyopathy (DCM). Cardiac magnetic resonance (CMR) imaging has been useful for excluding other causes.3 However, it is an unusual method and is difficult for patients with impaired renal function.
Thus, the purpose of this study was to clarify the characteristics of TCM before AF ablation. These should help establish early and optimal examinations, such as transesophageal echocardiography or enhanced computed tomography (CT), and treatments, such as AF ablation or cardioversion.
2 Methods
2.1 Study population