Abstract: Objcctivc The breakdance-mutation (bretb 218) has been described as a mutation in the zebrafish orthologe of the human ether-a-go-go-related gene (HERG,kcnh2) with an arrhythmic heart beat in the homozygous. Interestingly, we found the heterozygous (hets) could generate multiple premature aging-like features and distinct electrophysiology. It made possible to develop a vertebrate model for study on premature aging associated to kcnh2. Methods Life span and body shape change were followed up and recorded. Exercise endurance capacity was examined by swim test. ECG test was performed in wild type (WT) and the hets at different adult stages. Results Survival rate dramatically descended and curly body showed from 20 months in the hets. ECG test showed heart rate dramatically decreased along aging process and QTc duration prolonged in the hets. Exercise endurance capacity significantly reduced 56.44% in the hets at 32 months comparing to WT at the same stage.Conclusion The heterozygous breib 218 has shorter life span and showed the presenility on appearance， electrophysiology and the exercise endurance capacity which may associate to the mutation in one allele of zebrafish orthologue of kcnh2.

Key words: Zebrafish, Breakdance-mutation;Spinal curvature, Exercise endurance capacity, ECG