Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs.

BACKGROUND: Recurrent ventricular tachycardia among survivors of myocardial infarction with an implantable cardioverter-defibrillator (ICD) is frequent despite antiarrhythmic drug therapy. The most effective approach to management of this problem is uncertain. METHODS: We conducted a multicenter, randomized, controlled trial involving patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite the use of antiarrhythmic drugs. Patients were randomly assigned to receive either catheter ablation (ablation group) with continuation of baseline antiarrhythmic medications or escalated antiarrhythmic drug therapy (escalated-therapy group). In the escalated-therapy group, amiodarone was initiated if another agent had been used previously. The dose of amiodarone was increased if it had been less than 300 mg per day or mexiletine was added if the dose was already at least 300 mg per day. The primary outcome was a composite of death, three or more documented episodes of ventricular tachycardia within 24 hours (ventricular tachycardia storm), or appropriate ICD shock. RESULTS: Of the 259 patients who were enrolled, 132 were assigned to the ablation group and 127 to the escalated-therapy group. During a mean (±SD) of 27.9±17.1 months of follow-up, the primary outcome occurred in 59.1% of patients in the ablation group and 68.5% of those in the escalated-therapy group (hazard ratio in the ablation group, 0.72; 95% confidence interval, 0.53 to 0.98; P=0.04). There was no significant between-group difference in mortality. There were two cardiac perforations and three cases of major bleeding in the ablation group and two deaths from pulmonary toxic effects and one from hepatic dysfunction in the escalated-therapy group. CONCLUSIONS: In patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite antiarrhythmic drug therapy, there was a significantly lower rate of the composite primary outcome of death, ventricular tachycardia storm, or appropriate ICD shock among patients undergoing catheter ablation than among those receiving an escalation in antiarrhythmic drug therapy. (Funded by the Canadian Institutes of Health Research and others; VANISH ClinicalTrials.gov number, NCT00905853.).

Quality of life with ablation or medical therapy for ventricular arrhythmias: A substudy of VANISH.

BACKGROUND/OBJECTIVE: We compared health-related quality of life (HRQoL) in patients randomized to escalated therapy and those randomized to ablation for ventricular tachycardia in the VANISH trial. METHODS: HRQoL was assessed among VANISH patients at baseline and 3-, 6-, and 12-month follow-up visits. Four validated instruments were used: the SF-36, the implanted cardioverter defibrillator (ICD) Concerns questionnaire (ICDC), the Hospital Anxiety and Depression Scale (HADS), and the EuroQol five dimensions questionnaire (EQ-5D). Linear mixed-effects modeling was used for repeated measures with SF-36, HADS, ICDC, and EQ-5D as dependent variables. In a second model, treatment was subdivided by amiodarone use prior to enrollment. RESULTS: HRQoL did not differ significantly between those randomized to ablation or escalated therapy. On subgroup analysis, improvement in SF-36 measures was seen at 6 months in the ablation group for social functioning (63.5-69.3, P = 0.03) and energy/fatigue (43.0-47.9, P = 0.01). ICDC measures showed a reduction in ICD concern in the ablation group at 6 months (10.4-8.7, P = 0.01) and a reduction in ICD concern in the escalated therapy group at 6 months (10.9-9.4, P = 0.04). EQ-5D measures showed a significant improvement in overall health in ablation patients at 6 months (63.4-67.3, P = 0.04). CONCLUSION: Patients in the VANISH study randomized to ablation did not have a significant change in quality of life outcomes compared to those randomized to escalated therapy. Some subgroup findings were significant, as those randomized to ablation showed persistent improvement in SF-36 energy/fatigue and ICD concern, and transient improvement in SF-36 social functioning and EQ-5D overall health.

Lead Integrity Alert Is Useful for Assessment of Performance of Biotronik Linox Leads.

INTRODUCTION: Medtronic's Lead Integrity Alert (LIA) software algorithm is useful for detecting abnormal parameters across various ICD-lead families. However, its utility in the assessment of the Biotronik Linox™ family of high-voltage (HV) leads is unknown. METHODS: We conducted a retrospective cohort study to assess the performance of the LIA algorithm to detect abnormalities and lead failure in Linox ICD-leads. All LIA-enabled Medtronic devices connected to an active Linox lead were included. The alerts were adjudicated by 2 blinded electrophysiologists and correlated with clinical data. RESULTS: Between 2008 and 2012, data from 208 patients with 564 patient-years of follow-up were available for analysis. The median follow-up duration was 32 (IQR 21-41 months). Twenty-one LIA triggers were noted in 20 different patients. The median delay until a positive LIA was 32 months (IQR 21-41 months) postimplant with a 5-year lead survival free from LIA of 76%. Ninety-five percent (19/20) LIA alerts were true lead failures. The most common LIA triggers were short V-V intervals (85%) and nonsustained ventricular tachycardia (85%). Abrupt changes of the ICD-lead impedance occurred in 5/20 triggers. Inappropriate ICD-shocks were strongly associated with a positive LIA (30% vs. 7.4%; P = 0.006). Of the explanted Linox leads 53% had visible abnormalities. The sensitivity, specificity, and positive predictive value for lead failure in the presence of a LIA trigger were 87%, 99.5%, and 95.2%, respectively. CONCLUSIONS: A positive LIA trigger in Biotronik Linox ICD-leads is highly predictive of lead failure. LIA is useful in ongoing surveillance of lead performance.

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.

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.

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.

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.