Reduction of inappropriate implantable cardioverter-defibrillator therapies using enhanced supraventricular tachycardia discriminators: the ReduceIT study.

PURPOSE: Inappropriate implantable cardioverter-defibrillator (ICD) shocks are associated with greater healthcare resource utilization, poorer quality-of-life, and higher mortality. We aimed to investigate the performance of enhanced supraventricular tachycardia (SVT) discrimination algorithms (morphology discrimination, rate stability, and sudden or chamber onset) for reducing inappropriate ICD therapies in patients with ICD/cardiac resynchronization therapy devices. METHODS: This prospective, non-randomized, multicenter study (ReduceIT) study took place at 56 sites across Germany and Estonia. Adults at risk of sudden cardiac death undergoing St. Jude Medical™ ICD or CRT-D implantation were included. The primary endpoint was freedom from inappropriate ICD shock at 12 months and was analyzed in the intention to treat (ITT) and per-protocol population. RESULTS: Overall, 733 patients (65.9 ± 11.4 years) were included, of which 40.9% and 59.1% received a single- and dual-chamber detection device, respectively. During follow-up (median 11.9 [0-21.6] months), 96.3% of patients experienced no inappropriate therapy (ITT). The sensitivity, specificity, and accuracy for VT/VF were 91.9%, 95.5%, and 94.7%, respectively. In the per-protocol population (n = 620), the proportion of patients free from inappropriate shock at 12 months was 98.4% (n = 610; 95% CI 97.1-99.2%) and exceeded the expected value of 93% (p < 0.0001) which was derived from the rates in the SPICE, ATPonFastVT, and DECREASE studies. A total of 44 patients (6.0%) died during follow-up, 19 deaths were cardiac-related which is consistent with a meta-analysis of EMPIRIC, MADIT-RIT, ADVANCE III, and PROVIDE. Serious device and procedure-related adverse effects occurred in 9.8% of patients. CONCLUSIONS: In ICD/CRT-D devices with advanced SVT discriminators, device programming according to clinical setting and detection chamber significantly reduces the rate of inappropriate ICD shocks without compromising patient safety. The algorithms and settings described herein have particular clinical importance and their employment may be of benefit to ICD recipients.

INvestigation on Routine Follow-up in CONgestive HearT FAilure Patients with Remotely Monitored Implanted Cardioverter Defibrillators SysTems (InContact).

BACKGROUND: In heart failure (HF) patients with implantable cardioverter defibrillators (ICD) or cardiac resynchronisation therapy defibrillators (CRT-D), remote monitoring has been shown to result in at least non-inferior outcomes relative to in-clinic visits. We aimed to provide further evidence for this effect, and to assess whether adding telephone follow-ups to remote follow-ups influenced outcomes. METHODS: InContact was a prospective, randomised, multicentre study. Subjects receiving quarterly automated follow-up only (telemetry group) were compared to those receiving personal physician contact. Personal contact patients were further divided into those receiving automated follow-up plus a telephone call (remote+phone subgroup) or in-clinic visits only. RESULTS: Two hundred and ten patients underwent randomisation (telemetry n = 102; personal contact n = 108 [remote+phone: n = 53; visit: n = 55]). Baseline characteristics were comparable between groups and subgroups. Over 12 months, 34.8% of patients experienced deterioration of their Packer Clinical Composite Response, with no significant difference between the telemetry group and personal care (p > 0.999), remote+phone (p = 0.937) or visit (p = 0.940) patients; predefined non-inferiority criteria were met. Mortality rates (5.2% overall) were comparable between groups and subgroups (p = 0.832/p = 0.645), as were HF-hospitalisation rates (11.0% overall; p = 0.605/p = 0.851). The proportion of patients requiring ≥1 unscheduled follow-up was nominally higher in telemetry and remote+phone groups (42.2 and 45.3%) compared to the visit group (29.1%). Overall, ≥ 1 ICD therapy was delivered to 15.2% of patients. CONCLUSION: In HF patients with ICDs/CRT-Ds, quarterly remote follow-up only over 12 months was non-inferior to regular personal contact. Addition of quarterly telephone follow-ups to remote monitoring does not appear to offer any clinical advantage. TRIAL REGISTRATION: clinicaltrials.gov: NCT01200381 (retrospectively registered on September 13th 2010).

Reduction of inappropriate ICD therapies in patients with primary prevention of sudden cardiac death: DECREASE study.

BACKGROUND: A significant number of patients with an implantable cardioverter/defibrillator (ICD) for primary prevention receive inappropriate shocks. Previous studies have reported a reduction of inappropriate therapies with simple modifications of ICD detection settings, however, inclusion criteria and settings varied markedly between studies. Our aim was to investigate the effect of raising the ICD detection zone in the entire primary prevention ICD population. METHODS AND RESULTS: 543 patients receiving an ICD for primary prevention were randomized to either conventional or progressive ICD programming. The detection rate was programmed at 171 bpm for ventricular tachycardia (VT) and 214 bpm for ventricular fibrillation (VF) in the Conventional group and 187 bpm for VT and 240 bpm for VF in the Progressive group. 43 % of patients received single-chamber and 57 % dual-chamber detection devices (DDD-ICD 19 %; CRT-D 38 %). The primary endpoint consisted of inappropriate therapies and untreated VT/VF. The primary endpoint was reached in 35 patients (13 %) in the Conventional group and 17 patients (6 %) in the Progressive group (p = 0.004). Progressive ICD programming led to significantly fewer amount of patients with ICD therapies (26 vs. 14 %; p < 0.001) and shocks (11 vs. 5 %; p = 0.023) compared to conventional ICD programming. Sub-analyses showed the greatest reduction of inappropriate therapies and shocks in dual-chamber detection devices with progressive compared to single-chamber detection devices with conventional ICD programming (p < 0.001). CONCLUSIONS: Progressive ICD programming reduces the number of inappropriate therapies and shocks in a broad primary prevention ICD population particularly in combination with dual-chamber detection algorithms. CLINICAL TRIAL REGISTRATION: http://clinicaltrials.gov ; ClinicalTrials.gov identifier NCT01217528.

Clinical efficacy of left ventricular pacing vector programmability in cardiac resynchronization therapy defibrillator patients for management of phrenic nerve stimulation and/or elevated left ventricular pacing thresholds: insights from the Efface Phrenic Stim study.

AIMS: Elevated left ventricular (LV) pacing thresholds or phrenic nerve stimulation (PNS) might be possible reasons for absence of continuous and effective biventricular stimulation. This study investigated the benefit and clinical efficacy of the ability to choose one out of three different LV pacing vectors for the management of suboptimal LV pacing thresholds and PNS. METHODS AND RESULTS: This prospective, observational multicentre study enrolled 132 patients (Pts) implanted with a cardiac resynchronization therapy defibrillator, that offers three LV pacing vectors: (i) Bipolar; (ii) LVtip ↔ RVcoil; (iii) LVring ↔ RVcoil (RV = right ventricular). Left ventricular pacing thresholds and PNS thresholds were obtained in sitting and left lateral body position for all programmable LV pacing vectors at hospital discharge and follow up (FU). In 97%, a bipolar transvenous LV lead was successfully implanted. In 87% of Pts at least one acceptable pacing vector could be identified that provides good pacing threshold (≤ 2.5 V at 5 ms) and acceptable margin to PNS (≥ 2:1). This is an increase of 18% compared with conventional bipolar systems (74%) with two LV vectors and of 25% compared with unipolar systems (70%). The LVtip ↔ RVcoil vector provided the best LV pacing thresholds, but the highest rate of PNS. CONCLUSIONS: The programmability of LV pacing vectors is a powerful feature to avoid PNS and obtain acceptable LV pacing thresholds. In order to retain reprogramming options for LV vectors during FU, LV pacing leads with at least two electrodes should be chosen whenever possible.

Rationale and design of the SPICE study-septal positioning of ventricular ICD electrodes.

AIM: Detrimental effects of right ventricular apical pacing have prompted the search for alternative pacing sites. Data from pacemaker studies suggest that the mid-septum may be a hemodynamically favorable pacing site within the right ventricle. However, data on the safety of implantable cardioverter defibrillator (ICD) lead placement in this location are limited. The aim of the SPICE study is to ascertain that implantation of a ventricular ICD lead at the mid-septum is not inferior to the traditional apical site in terms of feasibility and safety. METHODS: In total, 286 patients with the indication for ICD implantation will be included in the study and stratified in a 1:1 ratio to have the lead placed in the right ventricular apex or the mid-septum. Primary outcome measure of this randomized, prospective study is the event-free survival of lead-related complications at 3 months. The combined end point includes the feasibility to reach the randomized pacing site in combination with the achievement of adequate pacing, sensing, and defibrillation thresholds. Data analysis and sample size calculation are based on a non-inferiority design. CONCLUSION: This trial will primarily assess the feasibility, safety, and efficacy of right ventricular ICD lead positioning in the mid-septum compared to the traditional apical position. Documentation of non-inferiority of the novel lead position in terms of applicability and safety will be the prerequisite for potential further trials that may evaluate long-term clinical effects associated with mid-septal lead positions.

Impact of moderate exercise workload on predicted optimal AV and VV delays determined by an intracardiac electrogram-based method for optimizing cardiac resynchronization therapy.

AIMS: Aim of this study is to evaluate reproducibility, consistency and the impact of moderate exercise workload on optimized PV and VV delays as determined by the IEGM-based QuickOpt™ method (St. Jude Medical), that was shown to produce hemodynamic performance similar to that obtained by echo-guided aortic VTI maximization. METHODS: Sixty patients with CRT-ICD (65 ± 9 years, 12% female, LVEF 28 ± 9%, 48% CAD and 52% DCM) were enrolled. IEGM-based PV/VV optimization was conducted six times: twice at rest, twice immediately after a 6-min walk test and twice following a 3-min recovery period. Timing cycle delays were programmed in accordance with the optimization results. Follow-up was performed after 1 year. RESULTS: Although significant difference in heart rate was reached [68 ± 9 bpm (REST) vs. 79 ± 12 (6MWT), p < 0.001], differences were not observed between IEGM-based optimized PV/VV delays: PV(opt) = 128 ± 14 ms (REST) versus 130 ± 17 ms (6MWT) versus 129 ± 16 ms (RECOV); VV(opt) = 15 ± 24 ms (REST) versus 15 ± 22 ms (6MWT) versus 16 ± 24 ms (RECOV). During 1-year follow-up PV(opt) and VV(opt) remained stable (ΔPV(opt) = 10 ± 10 ms, ΔVV(opt) = 9 ± 11 ms). CONCLUSION: Optimized IEGM-based timing cycle delays are independent of moderate exercise status within a particular patient but varied between patients. This supports the use of PV/VV optimization in each CRT patient.

A new method to investigate the response to the morphology discrimination algorithm in patients with ICD.

BACKGROUND: Inappropriate therapy for supraventricular tachyarrhythmia is still a major problem in implantable cardioverter defibrillators (ICD). The morphology discrimination algorithm compares the morphology of a tachycardia electrogram with a stored template on a beat-to-beat basis. However, algorithm responders could not yet be identified prior to the occurrence of first tachycardia episodes. We analyzed whether rapid atrial pacing and/or exercise testing can be used for identification of responders and compared the results with ICD detected tachycardia. METHODS: 22 patients (16 male, 61+/-14 years) with dual-chamber ICDs have been enrolled. Patients underwent a standardized bicycle exercise testing and an atrial pacing protocol. For both tests, morphology match scores of 8 consecutive beats were analyzed for each 10-bpm-step increment above sinus rhythm. Patients were categorized as responders, if morphology match was > or = 90% of tested heart rates. During follow-up, ICD stored episodes with morphology discrimination activated were evaluated. RESULTS: There were no significant differences between morphology match (85+/-29% vs. 84+/-27%) and linear regression slope B (-0.19+/-0.87 vs. -0.20+/-0.48) during exercise testing and atrial pacing. 16 patients (73%) were classified as responders. During follow-up (739+/-338 days) 121 sustained supraventricular (n=88) and ventricular tachycardia (n=33) were detected in 10 patients (45%). Specificity for tachycardia discrimination was 78% overall, 100% in responders and 22% in non-responders. CONCLUSION: Exercise testing and atrial pacing were equally suitable for identification of patients who seem to respond to the morphology discrimination algorithm with a high specificity for ventricular tachycardia discrimination. Thus, morphology match tests are suggested to optimize tachycardia discrimination and to reduce inadequate therapies.