Additional electrodes on the Quartet™ LV lead provide more programmable pacing options than bipolar and tripolar equivalents.

AIMS: The aim of this study was to evaluate any benefits to the number of viable pacing vectors and maximal spatial coverage with quadripolar left ventricular (LV) leads when compared with tripolar and bipolar equivalents in patients receiving cardiac resynchronization therapy (CRT). METHODS AND RESULTS: A meta-analysis of five previously published clinical trials involving the Quartet™ LV lead (St Jude Medical, St Paul, MN, USA) was performed to evaluate the number of viable pacing vectors defined as capture thresholds ≤2.5 V and no phrenic nerve stimulation and maximal spatial coverage of viable vectors in CRT patients at pre-discharge (n = 370) and first follow-up (n = 355). Bipolar and tripolar lead configurations were modelled by systematic elimination of two and one electrode(s), respectively, from the Quartet lead. The Quartet lead with its four pacing electrodes exhibited the greatest number of pacing vectors per patient when compared with the best bipolar and the best tripolar modelled equivalents. Similarly, the Quartet lead provided the highest spatial coverage in terms of the distance between two furthest viable pacing cathodes when compared with the best bipolar and the best tripolar configurations (P < 0.05). Among the three modelled bipolar configurations, the lead configuration with the two most distal electrodes resulted in the highest number of viable pacing vectors. Among the four modelled tripolar configurations, elimination of the second proximal electrode (M3) resulted in the highest number of viable pacing options per patient. There were no significant differences observed between pre-discharge and first follow-up analyses. CONCLUSION: The Quartet lead with its four electrodes and the capability to pace from four anatomical locations provided the highest number of viable pacing vectors at pre-discharge and first follow-up visits, providing more flexibility in device programming and enabling continuation of CRT in more patients when compared with bipolar and tripolar equivalents.

Trends in Use and Adverse Outcomes Associated with Transvenous Lead Removal in the United States.

BACKGROUND: Transvenous lead removal (TLR) has made significant progress with respect to innovation, efficacy, and safety. However, limited data exist regarding trends in use and adverse outcomes outside the centers of considerable experience for TLR. The aim of our study was to examine use patterns, frequency of adverse events, and influence of hospital volume on complications. METHODS AND RESULTS: Using the Nationwide Inpatient Sample, we identified 91 890 TLR procedures. We investigated common complications including pericardial complications (hemopericardium, cardiac tamponade, or pericardiocentesis), pneumothorax, stroke, vascular complications (consisting of hemorrhage/hematoma, incidents requiring surgical repair, and accidental arterial puncture), and in-hospital deaths described with TLR, defining them by the validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code. We specifically assessed in-hospital death (2.2%), hemorrhage requiring transfusion (2.6%), vascular complications (2.0%), pericardial complications (1.4%), open heart surgery (0.2%), and postoperative respiratory failure (2.4%). Independent predictors of complications were female sex and device infections. Hospital volume was not independently associated with higher complications. There was a significant rise in overall complication rates over the study period. CONCLUSIONS: The overall complication rate in patients undergoing TLR was higher than previously reported. Female sex and device infections are associated with higher complications. Hospital volume was not associated with higher complication rates. The number of adverse events in the literature likely underestimates the actual number of complications associated with TLR.

The impact of transvenous lead extraction on tricuspid valve function.

BACKGROUND: Few data exist regarding the effect of transvenous lead extraction (TLE) on tricuspid valve function. The objective of this study was to examine the effect of TLE on the development of postprocedure tricuspid regurgitation (TR). OBJECTIVE: To assess the impact of TLE on tricuspid valve function. METHODS: A single center retrospective analysis of consecutive patients referred for TLE between June 2006 and November 2011. Patients were included only if they underwent transthoracic echocardiography (TTE) before and after lead extraction (N = 124). Patients were assigned a preprocedure and postprocedure TR score on a continuous scale from 0 to 6 (0 = none, 1 = trace, 2 = mild, 3 = mild/moderate, 4 = moderate, 5 = moderate/severe, and 6 = severe). A clinically significant increase in TR was defined as both (1) an increase in TR score of at least two points, and (2) a postprocedure TR score ≥4 (moderate). RESULTS: A total of 124 patients referred for TLE underwent a TTE both before (9 ±16 months) and after lead extraction (4 ± 8 months). A total of 200 leads (1.6 ± 0.8 per patient) were extracted. The mean change in TR score after lead extraction was +0.18 (95% confidence interval [CI] -0.03 to 0.39, P = 0.11). A clinically significant increase in TR occurred in 7/124 (5.6% [CI 2.3-11.3%]) patients. Age ≥75 (+0.45, [CI 0.07-0.84, P = 0.02]), removal of ≥2 leads (+0.40 [CI 0-0.81, P = 0.05]), and powered sheath-assisted extraction (+0.34 [CI 0.05-0.62, P = 0.02]) were significantly associated with an increase in TR score. CONCLUSION: TLE is rarely associated with the development of clinically significant TR. In our cohort, patient age ≥75 years, pacemaker as opposed to ICD, and removal of ≥2 leads predicted worsening TR.

The evolution of the cardiac implantable electronic device connector.

Cardiac implantable electronic devices (CIEDs) play a vital role in the management of cardiac rhythm disturbances. The devices are comprised of two primary components: a generator and lead joined by a connector. Original pacemaker lead connectors were created de novo at the time of implantation or replacement and were very unreliable. With the development of new lead designs, creation of a standard connector configuration, the IS-1 connector became mandatory. Similar connector development also occurred with the advent of the implantable cardioverter defibrillator (ICD), resulting in creation of the high voltage standard: the DF-1 connector. Differing from a pacemaker lead, the ICD lead connector requires one IS-1 connector and one or two DF-1 connectors, resulting in a large cumbersome lead connector and generator header block. Recently, a revolutionary quad pole single plug connector standard has been approved for market release. These are the single-pin DF4 and IS4 lead connectors that carry low- and high-voltage poles or all low-voltage poles, respectively. These connectors, together with new labeling guidelines, have simplified operative procedures and reduced errors, when mating lead connectors into the generator's connector block.

Mechanical esophageal displacement during catheter ablation for atrial fibrillation.

OBJECTIVE: To determine the feasibility and safety of esophageal displacement during atrial fibrillation (AF) ablation, to prevent thermal injury. BACKGROUND: Patients undergoing AF ablation are at risk of esophageal thermal injury, which ranges from superficial ulceration, to gastroparesis, to the rare but catastrophic atrioesophageal fistula. A common approach to avoid damage is luminal esophageal temperature (LET) monitoring; however, (1) temperature rises mandate interruptions in energy delivery that interrupt workflow and potentially decrease procedural efficacy, and (2) esophageal fistulas have been reported even with LET monitoring. METHODS: A cohort of 20 consecutive patients undergoing radiofrequency (RF) (16 patients) or laser balloon (4 patients) ablation of AF under general anesthesia. After barium instillation, the esophagus was deviated using an endotracheal stylet placed within a thoracic chest tube. LET monitoring was used during catheter ablation. Upper GI endoscopy was performed prior to discharge. RESULTS: At the pulmonary vein level, leftward deviation measured 2.8 ± 1.6 cm (range: 0.4-5.7) and rightward deviation 2.8 ± 1.8 cm (range: 0.5-4.9). The temperature rose to >38.5 °C in 3/20 (15%) patients. In these 3 patients, there was an average of 2 applications/patient that recorded temperatures >38.5 °C. No patient had a temperature rise > 40 °C. Endoscopy revealed no esophageal ulceration from thermal injury in 18/19 (95%) patients; the sole patient with a thermally mediated ulceration had an unusual esophageal diverticulum fully across the posterior left atrium. Twelve patients (63%) exhibited trauma related to instrumentation with no clinical sequelae. CONCLUSIONS: Mechanical esophageal deviation is feasible and allows for uninterrupted energy delivery along the posterior wall during catheter ablation of AF.

Acute electrical isolation is a necessary but insufficient endpoint for achieving durable PV isolation: the importance of closing the visual gap.

AIMS: Temporary, ablation-mediated effects such as oedema may cause reversible pulmonary vein (PV) isolation. To investigate this, point-by-point circumferential ablation was performed to achieve acute electrical PV isolation with an incomplete circumferential ablation line. Then, the impact of this intentional 'visual gap' (ViG) on the conduction properties of the ablation lesion set was assessed with adenosine and pacing manoeuvres. METHODS AND RESULTS: Twenty-eight patients undergoing ablation for paroxysmal (n= 20) or persistent atrial fibrillation (n= 8) were included. Pulmonary vein (PV) ablation was performed around ipsilateral vein pairs. Once acute isolation was achieved, ablation was halted and the presence and size of the ViG were calculated. The ViG electrophysiological properties were tested with pace capture along the ViG at 10 mA/2 ms, and assessment for dormant PV conduction with adenosine. Despite electrical isolation, a ViG was present in 75% (n= 42/56) of vein pairs (21 of 28 left PVs and 21 of 28 right PVs). There was no difference in the ViG size between the left and right PVs (22.1 ± 14.2 and 17.3 ± 11.3 mm, P > 0.05). Dormant PV connections were revealed by adenosine in more than a quarter (n= 12/42) of acutely isolated PV pairs, of which the majority were dependent on conduction through the ViG. CONCLUSIONS: Electrical PV isolation can usually be achieved without complete circumferential ablation. However, more than a quarter of these 'isolated' PVs exhibit dormant conduction-predominantly via the un-ablated 'ViGs' in the ablation lesion set. These findings support the hypothesis that reversible tissue injury contributes to PV isolation that may be acute but not necessarily durable.

The Florida Shock Anxiety Scale (FSAS) for patients with implantable cardioverter defibrillators: testing factor structure, reliability, and validity of a previously established measure.

BACKGROUND: The implantable cardioverter defibrillator (ICD) reduces mortality in patients at risk for life-threatening arrhythmias via high energy shock. The Florida Shock Anxiety Scale (FSAS) was developed to measure ICD patient shock-related anxiety. Initial psychometric evaluation revealed good reliability and validity. The purpose of this study was to examine the psychometrics of the FSAS in a large US sample of ICD patients. METHODS: Participants were recruited via e-mail and the survey was completed online. Ultimately, 443 ICD patients (359 male and 421 White) completed the 10-item FSAS. RESULTS: Means for FSAS were comparable to previously published data (M = 15.18, SD = 6.5). Interitem reliability was good (Cronbach's α= 0.89). The FSAS was negatively correlated with single-item measures of emotional well-being (r =-0.378, P < 0.01), sense of security (r =-0.365, P < 0.01), perceived general health (r =-0.185, P < 0.01), and quality of life (r =-0.216, P < .01), demonstrating discriminant validity. Convergent validity was supported through significant correlations with number of shocks (r = 0.464, P < 0.01) and reported disruptiveness of shock (r = 0.484, P < 0.01). Confirmatory factor analysis revealed that a single (second-order) factor model (χ(2) [34] = 75.34, P < 0.05, comparative fit index = 0.98, root mean-square error of approximation = 0.05) had the best fit. CONCLUSIONS: Shock anxiety as a construct can be measured in a reliable and valid method by the FSAS. These nationally representative data suggest that a single score for shock anxiety is an easy to use and appropriate method of assessment.

Novel ventricular tachyarrhythmia detection enhancement detects undertreated life-threatening arrhythmias.

BACKGROUND: Ventricular tachyarrhythmias (VTA) with low and varying signal amplitudes and morphologies may not be successfully identified utilizing traditional implantable cardioverter-defibrillator algorithms. OBJECTIVE: Develop and validate a novel algorithm (VF Therapy Assurance, VFTA) to improve detection and timely delivery of high-voltage therapy (HVT) for these arrhythmias. METHODS: Arrhythmia detection was simulated on recorded VTA electrograms (EGMs) utilizing Abbott's Merlin.net database. EGMs where an HVT occurred only when VFTA was enabled, or where VFTA provided an HVT >30 seconds earlier than without VFTA, were readjudicated with physician review. As VFTA never prevents detection or therapy, EGMs where VFTA did not activate or alter HVT were not adjudicated. RESULTS: Among 564,353 recorded VTA EGMs from 20,000 devices, VFTA altered HVT in 105 EGMs from 67 devices. Physician adjudication determined that 81.9% (86/105) of these EGMs were true undertreated VTA episodes and would have received appropriate HVT with VFTA enabled. Furthermore, 65% of the episodes (56/86) were ventricular fibrillation, were polymorphic, did not self-terminate during the recording window, or were not amenable antitachycardia pacing. Of those, 87.5% (49/56) would not have elicited HVT without VFTA. Overall, VFTA provided new or earlier appropriate HVT in 0.27% (53/20,000) of devices with an increase in inappropriate HVT in 0.07% (14/20,000) devices. CONCLUSION: The VFTA algorithm successfully identifies VTA missed by traditional detection algorithms, owing to undersensed ventricular signals resulting in the rate falling below the programmed detection rate. The use of VFTA increases the likelihood of delivering life-saving HVT.

Real-world Adoption of Smartphone-based Remote Monitoring Using the Confirm Rx™ Insertable Cardiac Monitor.

While previous generations of insertable cardiac monitors (ICMs) required a bedside monitor for remote monitoring (RM), the Confirm Rx™ ICM (Abbott, Chicago, IL, USA) utilizes Bluetooth®, Wi-Fi/cellular technology, and a smart device to connect to the RM system. We aimed to characterize compliance, connectivity, and event transmission timing with the Confirm Rx™ ICM RM system. The study cohort included American patients who received the Confirm Rx™ ICM with SharpSense™ technology within three months of release (May-July 2019). Compliance with RM was quantified as the proportion of patients registering the patient app on their smart device and transmitting at least once. Connectivity was measured as the median number of days between consecutive transmissions per patient. Event transmission time was measured from episode detection to availability on the Merlin.net™ RM system (Abbott). Time from transmission until review by a clinician was examined. Values for device connectivity, episode transmission timing, and clinician view times were reported as median [first quartile, third quartile]. Of 5,666 patients who received a Confirm Rx™ ICM, 97% registered their patient app and 92% transmitted data at least once. Among those utilizing RM (aged 66 ± 15 years; 49% female), connectivity occurred every 1.5 [1.2, 2.4] days, or 4.7 times per week. Patient-reported symptoms were transmitted to Merlin.net™ within 2.9 [2.1, 3.8] minutes of event onset and viewed by the clinician within 0.9 [0.4, 3.1] days, while device-detected episodes without symptoms were transmitted within 18.5 [11.2, 36.5] hours and then viewed within 0.8 [0.3, 2.5] days. This real-world study demonstrated excellent patient compliance with the smartphone-based RM paradigm enabled by Confirm Rx™, suggesting the suitability of this technology for future cardiac implantable devices.

Advantage of optimizing V-V timing in cardiac resynchronization therapy devices.

BACKGROUND: There is little consensus as to the benefits of interventricular (V-V) timing optimization in cardiac resynchronization therapy (CRT). A variety of parameters are currently used to optimize device timing. This study was designed to investigate the potential advantage of using 3D ejection fraction (EF) and aortic velocity-time integral (VTI) as measures of global left ventricular (LV) function to optimize ventricular activation in CRT devices. METHODS: Seventy-four patients seen in the Optimization Clinic with adequate echocardiographic images were included. Three aortic VTI and two 3D EF values were recorded at five V-V settings and the average value used. Aortic VTI and 3D EF were classified as the best, worst, and simultaneous setting values. Data were analyzed using a two-tailed paired t-test. RESULTS: Comparing the best to worst V-V timing settings, VTI improved by 4.7 ± 7.5 cm (P < 0.0001) and 3D EF by 9.9%± 5.7% (P < 0.0001). Comparing the simultaneous setting to the best V-V timing setting, VTI improved by 2.4 ± 2.1 cm (P < 0.0001) and 3D EF by 3.8%± 4.9% (P < 0.0001). Aortic VTI improved in 85% of patients and 3D EF improved in 72%. However, only 26% of the patients had the same optimal setting using aortic VTI and 3D EF yielding an r(2) value of 0.003. CONCLUSIONS: Individualized echocardiographic V-V optimization of CRT devices improves global LV function as measured by aortic VTI and 3D EF. Substantial differences in function were seen over an 80-ms range of V-V timing and optimization resulted in improved LV function in the majority of patients.

Fatal outcome in a pacemaker-dependent patient.

The recent advisory of Medtronic Sprint Fidelis leads has resulted in significant controversy over proper management of patients. The current manufacture's guidelines recommend programming specific device alerts with close follow-up and implantable cardioverter-defibrillator lead replacement in patients with evidence of breach in lead integrity. Recently, several studies have identified significant limitations in this method of surveillance. We report the case of a pacemaker-dependent patient with an ischemic cardiomyopathy, who presented with cardiac arrest and evidence of fracture of the pace/sense portion of a Sprint Fidelis lead during postmortem interrogation. Likely mechanisms leading to his ultimate demise are discussed.

Transfemoral snaring and stabilization of pacemaker and defibrillator leads to maintain vascular access during lead extraction.

BACKGROUND: Lead extraction is an effective method for removing pacemaker and defibrillator leads and to obtain venous access when central veins are occluded. OBJECTIVE: We report a series of patients who required lead extraction and preservation of vascular access requiring a vascular snare introduced from the femoral vein to provide traction on the lead. This technique allowed advancement of the extraction sheath beyond the level of vascular occlusion, preserving vascular access in all patients. METHODS: All patients had peripheral contrast venography performed immediately prior to the procedure to identify the site(s) of venous occlusion. An extraction sheath was employed and with direct manual traction, the lead tip pulled free from the myocardial surface prior to advancement of the sheath beyond the occlusion. A transfemoral snare was used to grasp the distal portion of the lead and traction was used to immobilize the lead. RESULTS: In all patients, transfemoral snaring of the leads was necessary to allow safe advancement of a sheath to open the occluded venous system. There were no complications in any of the patients. CONCLUSION: Our series demonstrates the simple and safe technique of transfemoral lead snaring to assist lead extraction and maintain vascular access in the setting of venous occlusion, when the distal lead tip pulls free of the myocardium before an extraction sheath is passed beyond the point of venous obstruction.

Multicenter prospective observational long-term follow-up study of endocardial cardiac resynchronization therapy using the Jurdham procedure.

BACKGROUND: Endocardial cardiac resynchronization therapy (eCRT) avoids the limitations and failures of coronary sinus (CS) resynchronization. However, data regarding long-term outcomes are lacking. OBJECTIVE: The purpose of this study was to report the long-term outcome of eCRT performed using the Jurdham procedure in a real-world setting. METHODS: eCRT was performed in patients who failed a CS implant or failed to respond to cardiac resynchronization therapy (CRT), or in selected patients requiring lifelong oral anticoagulation (OAC). Left ventricular ejection fraction (LVEF), New York Heart Association functional class (NYHA FC), and left ventricular stimulation parameters were assessed during long-term follow-up (FU). RESULTS: From August 2009 to March 2018, the Jurdham procedure was performed in 88 patients at 15 centers in 8 countries, with FU of 32.88 ± 61.52 months (range 0-88 months; 196 patient-years). NYHA FC improved from 2.9 preimplant to 1.3 during FU. LVEF increased <10 percentage points from baseline in 7% of patients, between 10 and 20 percentage points in 11% of patients, and >20 percentage points in 82% of patients. All-cause mortality at 60 months was 30.5%. Three transient ischemic attacks (1.53 per 100 patient-years) and 6 strokes (3.06 per 100 patient-years) occurred. Of the 6 patients with stroke, 4 (66%) had almost complete recovery. CONCLUSION: eCRT using the Jurdham procedure is an effective and safe technique in anticoagulated patients. This approach may be an attractive option for patients with failed CS implants or nonresponders to CS CRT. In addition, it might be a reasonable approach as a first option for treatment of patients requiring lifelong OAC.

Impact of implantable cardioverter-defibrillator recalls on patients' anxiety, depression, and quality of life.

BACKGROUND: In the past 2 years, multiple implantable cardioverter-defibrillator (ICD) manufacturers have issued recalls on ICD models due to the potential for serious malfunction and even patient death. Previous studies examining the relationship between these recalls and patients' psychological well-being have been limited by small sample size and conflicting results. The purpose of this study is to examine the association between ICD recalls and patients' anxiety, depression, and quality of life. METHODS: Patients were drawn from an outpatient electrophysiology clinic at a tertiary care hospital in New York City. Patients who had devices subject to a recall (cases) were identified from lists provided by device manufacturer and controls (patients with ICDs not subjected to a recall) were drawn from a convenience sample of outpatients. The survey instrument consisted of two validated questionnaires--Hospital Anxiety and Depression Score (HADS) and MacNew heart disease health-related quality of life (QOL) instrument. In addition, a series of Likert-type scales were designed to elucidate patients' concerns related to the following domains: anger, trust, hope, concerns regarding ICD shock, fear of death (FOD), and physicians' ability to reduce their concern about the ICD recall. Data were analyzed using simple descriptive statistics and bivariate analyses (chi(2) and t-test) as appropriate. RESULT: Sixty-one cases and 43 control patients were enrolled. Thirty-two patients (52%) with devices subject to a recall opted for a generator replacement. There were no significant differences in the mean scores on the HADS scale, or the MacNew QOL scale between these two groups of patients (cases and controls). Subgroup analysis within the group of patients whose ICDs were recalled (cases) revealed a reduced QOL among patients with a class I recall (reasonable probability that the product will cause serious adverse health consequences or death) as compared to those with a class II recall (product may cause temporary or medically reversible adverse health consequences) (P = 0.01). Both cases and control patients reported having reduced trust in the health-care system. On the whole, however, patients were satisfied with the way their physicians dealt with the recall. There was no significant change in the overall concern of ICD shocks or FOD between the two groups. CONCLUSION: In this study of ICD recall, we found no difference in the levels of anxiety, depression, or QOL expressed by patients with an ICD subject to a recall as compared to those without. These findings may be a reflection of good physician-patient communication, which might have reduced any anxiety associated with recalls.

Increased Hospitalizations and Overall Healthcare Utilization in Patients Receiving Implantable Cardioverter-Defibrillator Shocks Compared With Antitachycardia Pacing.

OBJECTIVES: The purpose of this study was to evaluate the effect of these therapies on healthcare utilization in a large patient cohort. BACKGROUND: Antitachycardia pacing (ATP) terminates ventricular tachycardia and avoids delivery of high-voltage shocks. Few data exist on the impact of shocks on healthcare resource utilization compared with ATP. METHODS: PROVIDE (Programming Implantable Cardioverter Defibrillators in Patients With Primary Prevention Indication) was a prospective study of patients who received an implantable cardioverter-defibrillator (ICD) for primary prevention at 97 U.S. centers (2008 to 2010). We categorized the PROVIDE patients by the type of therapy delivered: no therapy, ATP only, or at least 1 shock. All ICD therapies, hospitalizations, and deaths were adjudicated. Cumulative cardiac hospitalizations, risk of all-cause death or cardiac hospitalization, and annual costs were compared between groups. RESULTS: Of the 1,670 patients in PROVIDE, followed up for 18.1 ± 7.6 months, 1,316 received no therapy, 152 had ATP only, and 202 received at least 1 shock. Patients receiving no therapy and those receiving only ATP had a lower cumulative hospitalization rate and were at lower risk for death or hospitalization (hazard ratio: 0.33 [p < 0.001] and 0.33 [p < 0.002], respectively). The cost of hospitalization was $2,874 per patient-year (95% confidence interval: $877 to $5,140; p = 0.002) higher for those receiving at least 1 shock than for those who received ATP only. There was no difference in outcomes or cost between patients receiving only ATP and those without therapy. CONCLUSIONS: Among patients implanted with an ICD for primary prevention, those who received only ATP therapy had reduced hospitalizations, mortality, and cost compared with those who received at least 1 high-voltage shock and had equivalent outcomes to patients who did not require any therapy. (Programming Implantable Cardioverter Defibrillators in Patients With Primary Prevention Indication [PROVIDE]; NCT00743522).

Atrial fibrillation in hypertrophic cardiomyopathy: mechanisms, embolic risk and prognosis.

Hypertrophic cardiomyopathy (HCM) is associated with an increased incidence of supraventricular and ventricular arrhythmias. Atrial fibrillation (AF) is the most common arrhythmia in HCM with a prevalence of 20% and an annual incidence of two percent per year. Increased left atrial size and volume along with impaired left atrial function confer an increased likelihood of AF. The onset of AF is often accompanied by a decrease in functional status in conjunction with an increased risk of stroke and overall mortality.

Reduced Mortality Associated With Quadripolar Compared to Bipolar Left Ventricular Leads in Cardiac Resynchronization Therapy.

OBJECTIVES: The study sought to compare survival, lead deactivation, and lead replacement with quadripolar versus bipolar leads using a retrospective cohort of patients with newly implanted cardiac resynchronization therapy (CRT) systems. BACKGROUND: In CRT, quadripolar left ventricular (LV) leads offer alternative pacing sites and vectors not available with bipolar LV leads, which may improve the effectiveness of the therapy. METHODS: Using nationwide data from device implant registration records of a single manufacturer, we identified patients with a de novo cardiac resynchronization therapy with defibrillation (CRT-D) implanted between November 30, 2011, and May 31, 2013. Patients were followed for up to 24 months. The primary predictor was LV lead type (quadripolar Quartet [St. Jude Medical, St. Paul, Minnesota] LV lead or bipolar LV lead). The primary outcome was death and the secondary outcomes were LV lead replacement and deactivation. RESULTS: Among 23,570 patients (69.5 ± 11.1 years of age; 28% female; median follow-up time 1.14 years), 18,406 had quadripolar and 5,164 had bipolar LV leads. The quadripolar and bipolar groups had 5.04 and 6.45 deaths per 100 patient-years, respectively (p < 0.001). After multivariate adjustment, the quadripolar lead was associated with a lower risk of deactivation (hazard ratio [HR]: 0.62; 95% confidence interval [CI]: 0.46 to 0.84; p = 0.002), replacement (HR: 0.67; 95% CI: 0.55 to 0.83; p < 0.001), and death (HR: 0.77; 95% CI: 0.69 to 0.86; p < 0.001). CONCLUSIONS: In this observational study of CRT-D devices, use of a quadripolar, compared to a bipolar LV lead, was associated with a reduction in LV lead deactivation, replacement, and mortality.

Performance of an ICD algorithm to detect lead noise and reduce inappropriate shocks.

BACKGROUND: Implantable cardioverter-defibrillators (ICD) provide treatment for life-threatening ventricular tachyarrhythmias. Failure of the pace/sense conductor of an ICD lead can cause noise on the sensing electrogram (EGM) that may be misinterpreted as ventricular activity, triggering inappropriate therapy. An algorithm based upon the confirmation of ventricular activity from a far-field EGM has been developed to reduce inappropriate therapies resulting from this type of lead failure, while ensuring that appropriate therapy is delivered. The objectives of this study were to evaluate the algorithm's ability to discriminate lead noise from ventricular tachycardia/ventricular fibrillation (VT/VF) and to determine whether it inhibits inappropriate shocks without delaying appropriate shocks. METHODS: The algorithm was prospectively tested using near- and far-field EGM recordings from patients in three conditions: normal sinus rhythm with sustained and non-sustained lead noise via manipulation of the ICD pocket or lead system, and VT/VF induced during defibrillation threshold testing. The recordings were played through a bench-top device running the algorithm with the diagnosis, time to diagnosis, and inhibition of therapy documented. RESULTS: The algorithm detected noise and withheld inappropriate therapy in 231 of 238 recordings of sustained lead noise that would otherwise have been diagnosed as VT/VF (97.1%). Non-sustained lead noise was correctly diagnosed in 47 of the 52 recordings (90.4%). The device appropriately identified all 853 recordings of VT/VF (100%), without an increase in the time to detection (0.01 ± 0.14 s). CONCLUSIONS: The SecureSense(TM) algorithm correctly diagnosed sustained and non-sustained lead noise recordings without compromising detection of VT/VF. Use of the algorithm may reduce inappropriate shocks and alert clinicians to lead noise indicative of lead failure.

What did we learn from Riata™?

The Riata™ 8 French (Fr) and Riata ST™ 7 Fr families of silicone leads have experienced a specific form of insulation abrasion characterized by externalization of conductor cables outside the lead body. Design differences between the 8 Fr and 7 Fr leads make conductor externalization less likely in the smaller diameter lead. The Riata Lead Evaluation Study (RLES) reported on the prevalence of externalized conductors (EC) in patients implanted with Riata™ and Riata ST™ silicone leads and provided details on the incidence of electrical abnormalities in Riata™ and Riata ST™ leads with and without EC. The prevalence of EC was significantly lower for the Riata ST™ leads (7 Fr) as compared with Riata™ leads (8 Fr) (24/259 (9.3 %) vs. 125/517 (24.2 %), P < 0.001), and the majority of leads with EC were not associated with electrical malfunction. The aim of this manuscript is to describe the design of the Riata™ and Riata ST™ families of leads, provide details regarding the mechanisms and rates of lead failure, and discuss recommendations for patient management.