KCNQ³⁷⁰ mutant larvae take 1-2 days longer to develop, a reduced number of animals eclose, and the mean lifespan of females is reduced by 20-30%. Mutant adults show a drastically increased incidence of pacing-induced cardiac dysfunction compared to age-matched controls, and the elevated failure rates observed in young mutant flies does not increase further with age.

Semi-intact KCNQ³⁷⁰ fly heart preparations from young (1-3 week old) flies exhibit severely nonrhythmic beating patterns, and the incidence of arrhythmia increases more rapidly with age compared to control preparations. A dramatic age-dependent increase of the heart period (defined as the length of time between the ends of two consecutive diastolic intervals) compared with age-matched controls is also observed, and both diastolic intervals and systolic intervals show age-dependent increases in length.