The Coxsackievirus B3 (CVB3) belongs to the family of Picornaviridae and within this group to the genus of enteroviruses. The virus has a single-stranded, positive-sensed, and linear RNA genome that includes eleven genes encoding capsid proteins and non-structural proteins. The genome comprises a single, long open reading frame and during translation the generated polyprotein is cleaved by two virus-encoded proteinases. CVB3 has been associated with myocarditis, a cardiac disease represented by inflammation and injury of the myocardium. Acute infections in humans and murine models can be accompanied by ventricular arrhythmias and sudden cardiac death. Similar phenotypes can be observed when the function of cardiac ion channels is impaired. Here, we study the effect of a non-infectious CVB3 mutant on the functions of cardiac ion channels in Xenopus laevis oocytes using two electrode voltage clamp. As a result, several cardiac cation channels are modulated, while further investigated channels are not affected by the coexpression of CVB3. Further, the effect on the modulated channels is time-dependent. The incorporation of these in vitro data into a cardiac action potential model suggests a shortening of action potential duration during the first three days of infection. These data may help to explain the development of virus-induced arrhythmias during Coxsackievirus infection.