Current generations of implantable cardioverter defibrillators are capable of providing sophisticated dual chamber atrioventricular and rate-responsive pacing therapies, and even cardiac resynchronization therapy. Appropriate programming of the devices is necessary for them to perform all such sophisticated tasks. In this report, we describe a case where detection of ventricular tachycardia was delayed due to intradevice interactions between the pacemaker and defibrillator components of the device.