Evaluating hoarseness after cardiac surgery could be crucial to detecting decreased swallowing function. However, objectively detecting hoarseness has been difficult in daily clinical practice of cardiovascular domains, because it is only performed by skilled voice treatment specialists. Recently, some evaluating methods of hoarseness using artificial intelligence with its recent development have been reported. This exploratory study aimed to investigate the GRBAS (Grade, Roughness, Breathiness, Asthenia, Strain) scale items using an iPhone application "GRBASZero" for detecting aspiration following cardiac surgery.