A medical device lead includes a proximal connector configured to couple the lead to a pulse generator, and an insulative lead body extending distally from the proximal connector. The first lead conductor is coupled to the proximal connector and extends through the lead body. The medical device lead also includes a distal defibrillation electrode. A first spark gap is connected between the first lead conductor and the distal defibrillation electrode and has a breakdown voltage that prevents transmission of magnetic resonance imaging (MRI) induced signals from the first lead conductor to the distal defibrillation electrode in an MRI environment and allows transmission of therapy signals to the distal defibrillation electrode.