BACKGROUND/AIMS: Amiodarone is one of the most widely used antiarrhythmic agents; however, amiodarone-induced pulmonary toxicity (APT) can be irreversible and sometimes fatal. The aim of this study was to evaluate the feasibility of chest computed tomography (CT) as a diagnostic tool for APT and to assess the utility of the CT APT score as an index for predicting the severity of APT. METHODS: Patients underwent amiodarone treatment for various reasons, most often atrial fibrillation, for more than 2 years, and those that received a cumulative dose > 100 g were enrolled. A total of 34 patients who underwent chest CT between December 2011 and June 2012 were enrolled, whether or not they had clinical symptoms. The APT CT score was defined as the number of involved regions in the lung, which was divided into 18 regions (right and left, upper, middle, and lower, and central, middle, and peripheral). The CT findings were evaluated according to the total dose and duration of amiodarone treatment and the results of a pulmonary function test. Clinical symptoms and outcomes were also evaluated according to APT CT scores. RESULTS: Seven patients had positive APT CT scores (interstitial fibrosis in five, organizing pneumonia in one, and mixed interstitial fibrosis and organizing pneumonia in one), and these patients exhibited significantly lower diffusion capacity for carbon monoxide in the lungs compared with patients without an increased APT CT score (70.2% +/- 6.9% vs. 89.7% +/- 19.4%; p = 0.011). Three of the seven patients experienced overt APT that required hospital admission. CONCLUSIONS: Chest CT is a useful diagnostic tool for APT, and the APT CT score might be a useful index for assessing the severity of APT.
Aged ; Amiodarone/*adverse effects ; Anti-Arrhythmia Agents/*adverse effects ; Atrial Fibrillation/diagnosis/*drug therapy ; Cross-Sectional Studies ; Cryptogenic Organizing Pneumonia/chemically induced/physiopathology/*radiography/therapy ; Feasibility Studies ; Female ; Forced Expiratory Volume ; Hospitalization ; Humans ; Lung/drug effects/physiopathology/*radiography ; Male ; Middle Aged ; Predictive Value of Tests ; Prospective Studies ; Pulmonary Diffusing Capacity ; Pulmonary Fibrosis/chemically induced/physiopathology/*radiography/therapy ; Respiratory Function Tests ; Risk Factors ; Time Factors ; *Tomography, X-Ray Computed ; Vital Capacity