The Canadian experience with Durata and Riata ST Optim defibrillator leads: a report from the Canadian Heart Rhythm Society Device Committee.

BACKGROUND: The St. Jude Medical Riata family of implantable cardioverter-defibrillator (ICD) leads has demonstrated a high rate of externalized conductors and electrical failure. OBJECTIVE: Given similar design elements of Durata to Riata, the purpose of this study was to assess the rates of failure of the Riata ST Optim and Durata lead families in Canada. METHODS: All Canadian ICD-implanting centers were invited to submit follow-up information on all Optim-coated ICD leads implanted. Electrical failure was defined as a rapid change in impedance or pacing capture threshold leading to lead revision, or oversensing due to noise. Externalized conductors were defined as appearance of conductor wires outside the lead body. Systematic fluoroscopic screening for externalized conductors was not performed. RESULTS: As of December 1, 2012, 15 of 25 centers provided data on 3981 leads (44% of those sold in Canada during the same timeframe): 3477 Durata and 504 Riata ST Optim leads. The most common model numbers were 7122 (1516 leads [38%]), 7121 (707 leads [18%]), and 7120 (622 leads [16%]). Mean follow-up duration from implant to December 1, 2012, was 4.47 ± 0.48 years for Riata ST Optim leads and 2.00 ± 1.10 years for Durata leads. The annual rate of lead failure was 0.27% per year for Riata ST Optim leads and 0.24% per year for Durata leads. No instances of externalized conductors were identified in the failed leads. No deaths were attributed to lead failure; however, 2 patients experienced inappropriate shocks due to lead failure. CONCLUSION: The overall electrical failure rates of the Riata ST Optim and Durata leads appear to be low, and no instances of externalized conductors were observed.

Real-time transmission to real-time patient care: a tale of 4 devices.

We report a case in which a patient with dilated cardiomyopathy presented with syncope, terminated by a shock from his implantable cardioverter defibrillator. However, subsequent interrogation of the device revealed no tachycardia detection or treatment parameters. The mystifying details of the case were unravelled by remote consultation with the staff electrophysiologist and the use of smart phone-transmitted live images. This case highlights the use of mobile phone-facilitated video conferencing in urgent management of intracardiac device therapy. Judicious use of this technology has the potential to deliver effective and cost-effective solutions for many device-related emergencies in patients at remote settings.

Using left-ventricular-only pacing to eliminate T-wave oversensing in a biventricular implantable cardiac defibrillator.

A man aged 75 years and with nonischemic cardiomyopathy had implantation of a biventricular implantable cardiac defibrillator (ICD). Consistent biventricular pacing was limited by intermittent T-wave oversensing (TWOS). A strategy of left-ventricular-only pacing was used to eliminate TWOS. This strategy obviates the need to reduce ventricular sensitivity and thus may be an effective alternative to biventricular pacing complicated by TWOS.

Long-term efficacy of cardiac pacemakers and implantable cardioverter/defibrillators.

Cardiac pacemakers and implantable cardioverter/defibrillators are becoming more common due to expanded indications and increasing patient survival. In addition, these device systems are being implanted in younger patients, which increases their necessity for long-term durability. Device adverse events can be seen early, during or following implantation (perforation, lead dislodgement, infection), or late (lead fraction, insulation failure or device system infection). These adverse events can, at least in part, be attributed to intrinsic device system structure. Since the initial pacemakers and implantable cardioverter/defibrillators, many modifications in both device system hardware and software have been made to enhance both their durability and function. The current era of devices appear to have made adjustments for previous inadequacies and promise to be reliable and to function well. Despite this, however, it is necessary for clinicians to be aware of possible malfunctions, their warning signs, and the appropriate course of action should these malfunctions be encountered. In this review we describe the common device system malfunctions and device system insertion complications.