Cardiac Resynchronization Therapy Implantable Cardioverter-defibrillator Research Articles

Implantable Cardioverter Defibrillator Multisensor Monitoring during Home Confinement Caused by the COVID-19 Pandemic.

Simple SummaryDuring the COVID-19 pandemic, utilization of remote monitoring platforms was recommended. The HeartLogic algorithm identifies patients at risk of heart failure events, combining multiple sensors available on implantable cardioverter defibrillators. This analysis examined how multiple CIED sensors behave in periods of anticipated restrictions pertaining to physical activity. We demonstrated a significant drop in median activity level immediately after the implementation of stay-at-home orders, whereas there was no difference in the other contributing sensors. The weekly rate of heart failure alerts was significantly higher during the lockdown and post-lockdown than that reported in the pre-lockdown. Aims: The utilization of remote monitoring platforms was recommended amidst the COVID-19 pandemic. The HeartLogic index combines multiple implantable cardioverter defibrillator (ICD) sensors and has proved to be a predictor of impending heart failure (HF) decompensation. We examined how multiple ICD sensors behave in the periods of anticipated restrictions pertaining to physical activity. Methods: The HeartLogic feature was active in 349 ICD and cardiac resynchronization therapy ICD patients at 20 Italian centers. The period from 1 January to 19 July 2020, was divided into three phases: pre-lockdown (weeks 1–11), lockdown (weeks 12–20), post-lockdown (weeks 21–29). Results: Immediately after the implementation of stay-at-home orders (week 12), we observed a significant drop in median activity level whereas there was no difference in the other contributing parameters. The median composite HeartLogic index increased at the end of the Lockdown. The weekly rate of alerts was significantly higher during the lockdown (1.56 alerts/week/100 pts, 95%CI: 1.15–2.06; IRR = 1.71, p = 0.014) and post-lockdown (1.37 alerts/week/100 pts, 95%CI: 0.99–1.84; IRR = 1.50, p = 0.072) than that reported in pre-lockdown (0.91 alerts/week/100 pts, 95%CI: 0.64–1.27). However, the median duration of alert state and the maximum index value did not change among phases, as well as the proportion of alerts followed by clinical actions at the centers and the proportion of alerts fully managed remotely. Conclusions: During the lockdown, the system detected a significant drop in the median activity level and generated a higher rate of alerts suggestive of worsening of the HF status.

Multiparametric Implantable Cardioverter-Defibrillator Algorithm for Heart Failure Risk Stratification and Management: An Analysis in Clinical Practice.

The HeartLogic algorithm combines multiple implantable cardioverter-defibrillator sensors to identify patients at risk of heart failure (HF) events. We sought to evaluate the risk stratification ability of this algorithm in clinical practice. We also analyzed the alert management strategies adopted in the study group and their association with the occurrence of HF events. The HeartLogic feature was activated in 366 implantable cardioverter-defibrillator and cardiac resynchronization therapy implantable cardioverter-defibrillator patients at 22 centers. The median follow-up was 11 months [25th-75th percentile: 6-16]. The HeartLogic algorithm calculates a daily HF index and identifies periods IN alert state on the basis of a configurable threshold. The HeartLogic index crossed the threshold value 273 times (0.76 alerts/patient-year) in 150 patients. The time IN alert state was 11% of the total observation period. Patients experienced 36 HF hospitalizations, and 8 patients died of HF during the observation period. Thirty-five events were associated with the IN alert state (0.92 events/patient-year versus 0.03 events/patient-year in the OUT of alert state). The hazard ratio in the IN/OUT of alert state comparison was (hazard ratio, 24.53 [95% CI, 8.55-70.38], P<0.001), after adjustment for baseline clinical confounders. Alerts followed by clinical actions were associated with less HF events (hazard ratio, 0.37 [95% CI, 0.14-0.99], P=0.047). No differences in event rates were observed between in-office and remote alert management. This multiparametric algorithm identifies patients during periods of significantly increased risk of HF events. The rate of HF events seemed lower when clinical actions were undertaken in response to alerts. Extra in-office visits did not seem to be required to effectively manage HeartLogic alerts. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02275637.

A multiparametric ICD algorithm for heart failure risk stratification and management: an analysis in clinical practice

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The HeartLogic algorithm combines multiple implantable cardioverter defibrillator (ICD) sensors to identify patients at risk of heart failure (HF) events. Purpose We sought to evaluate the risk stratification ability of this algorithm in clinical practice. We also analyzed the alert management strategies adopted in the study group and their association with the occurrence of HF events. Methods The HeartLogic feature was activated in 366 ICD and cardiac resynchronization therapy ICD patients at 22 centers. The HeartLogic algorithm automatically calculates a daily HF index and identifies periods IN or OUT of an alert state on the basis of a configurable threshold (in this analysis set to 16). Results The HeartLogic index crossed the threshold value 273 times (0.76 alerts/patient-year) in 150 patients over a median follow-up of 11 months [25-75 percentile: 6-16]. Overall, the time IN the alert state was 11% of the total observation period. Patients experienced 36 HF hospitalizations and 8 patients died of HF (rate: 0.12 events/patient-year) during the observation period. Thirty-five events were associated with the IN alert state (0.92 events/patient-year versus 0.03 events/patient-year in the OUT of alert state). The hazard ratio in the IN/OUT of alert state comparison was (HR: 24.53, 95% CI: 8.55-70.38, p &amp;lt; 0.001), after adjustment for baseline clinical confounders. Alerts followed by clinical actions were associated with a lower rate of HF events (HR: 0.37, 95% CI: 0.14-0.99, p = 0.047). No differences in event rates were observed between in-office and remote alert management. By contrast, verification of HF symptoms during post-alert examination was associated with a higher risk of HF events (HR: 5.23, 95% CI: 1.98-13.83, p &amp;lt; 0.001). Conclusions This multiparametric ICD algorithm identifies patients during periods of significantly increased risk of HF events. The rate of HF events seemed lower when clinical actions were undertaken in response to alerts. Extra in-office visits did not seem to be required in order to effectively manage HeartLogic alerts, while post-alert verification of symptoms seemed useful in order to better stratify patients at risk of HF events.

Implantable cardioverter defibrillator multisensor monitoring during home confinement caused by the covid-19 pandemic

Funding AcknowledgementsType of funding sources: None.BackgroundUtilization of remote monitoring platforms was recommended amidst the COVID-19 pandemic. The HeartLogic algorithm combines data from multiple implantable cardioverter defibrillator (ICD) sensors (first and third heart sounds, intrathoracic impedance, respirations, night heart rate, and patient activity) to provide integrated data that may allow for detection of early signs of worsening HF.PurposeWe examined whether the HeartLogic platform may elucidate behavioral changes that impact HF decompensation, and the possible consequences of home confinement caused by the COVID-19 pandemic.MethodsThe Italian lockdown was imposed from March 8th to May 18th. On March 8th 2020, the HeartLogic feature was active in 349 ICD and cardiac resynchronization therapy ICD patients at 20 Italian centers. The period from January 1st to July 19th was divided in 3 phases: Pre-Lockdown (weeks 1-11), Lockdown (weeks 12-20), Post-Lockdown (weeks 21-29).ResultsImmediately after the implementation of stay at home orders (week 12) we observed a significant drop in median activity level (65min [36-103] in week 12 vs. 101min [61-140] in Pre-Lockdown; p < 0.001), while there was no difference in the other contributing sensors. The median composite HeartLogic index increased at the end of Lockdown (4.7 [1.3-10.2] in week 20 vs. 2.5 [0.7-7.0] in Pre-Lockdown; p = 0.019). The weekly rate of HeartLogic alerts was significantly higher during Lockdown (1.56 alerts/week/100pts, 95%CI:1.15-2.06; IRR = 1.71, p = 0.014) and Post-Lockdown (1.37 alerts/week/100pts, 95%CI:0.99-1.84; IRR = 1.50, p = 0.072) than that reported in Pre-Lockdown (0.91 alerts/week/100pts, 95%CI:0.64-1.27). However, the median duration of alert state and the maximum index value did not change among phases, as well as the proportion of alerts followed by clinical actions at the centers (Pre-Lockdown: 31%, Lockdown: 22%, Post-Lockdown: 28%), and the proportion of alerts fully managed remotely (i.e. no in-clinic visits) (Pre-Lockdown: 89%, Lockdown: 90%, Post-Lockdown: 88%).ConclusionsThe system was sensitive to the behavioral changes occurred during the lockdown, i.e. decrease in activity. However, the home confinement had no impact on the other sensors. The higher rate of HeartLogic alerts during lockdown and the increase in the median index after 8 weeks of home confinement suggest the worsening of the HF status, possibly explained by the behavioral changes. Nonetheless, the management of the HF detected events (actions performed and management strategy) was not impacted by the restrictions.

Remote heart failure management using a multiparameter implantable cardioverter-defibrillator alert: the multicentric RE-HEART registry

Abstract Background The HeartLogic algorithm combines multiple implantable cardioverter-defibrillator (ICD)-based sensors into an index for prediction of impending heart failure (HF) decompensation. In patients with ICD and cardiac resynchronization therapy ICD remotely monitored at 13 Spanish centers, we analyzed the association between clinical events and HeartLogic alerts and we described the use of the algorithm for the remote management of HF. Methods The association between clinical events and HeartLogic alerts was studied in the blinded phase (from ICD implantation to alert activation – no clinical actions taken in response to alerts) and in the following active phase (after alert activation – clinicians automatically notified in case of alert). Results We enrolled a total of 215 patients (67±13 years old, 77% male, 53% with ischemic cardiomyopathy) with ICD (19%) or CRT-D (81%). The median duration of the blinded phase was 8 [3–12] months. In this phase, the HeartLogic index crossed the threshold value (set by default to 16) 34 times in 20 patients. HeartLogic alerts were associated with 6 HF hospitalizations and 5 unplanned in-office visits for HF. Five additional HeartLogic threshold crossings were not associated with overt HF events, but occurred at the time of changes in drug therapy or of other clinical events. The rate of unexplained alerts was 0.25 alert-patient/year. The median time spent in alert was longer in the case of HF hospitalizations than of in-office visits (75 [min-max: 30–155] days versus 39 [min-max: 5–105] days). The maximum HeartLogic index value was 38±15 in the case of hospitalizations and 24±7 in that of minor HF events. The median duration of the following active phase was 5 [2–10] months. After HeartLogic activation, 40 alerts were reported in 26 patients. Twenty-seven (68%) alerts were associated with multiple HF- or non-HF related conditions or changes in prescribed HF therapy. Multiple actions were triggered by these alerts: HF hospitalization (4), unscheduled in-office visits (8), diuretics increase (8), change in other cardiovascular drugs (5), device reprogramming (2), atrial fibrillation ablation (1), patient education on therapy adherence (2). The rate of unexplained alerts not followed by any clinical action was 0.13 alert-patient/year. These alerts were managed remotely (device data review and phone contact), except for one alert that generated an unscheduled in-office visit. Conclusions HeartLogic index was frequently associated with HF-related clinical events. The activation of the associated alert allowed to remotely detect relevant clinical conditions and to implement clinical actions. The rate of unexplained alerts was low, and the work required in order to exclude any impending decompensation did not constitute a significant burden for the centers. Funding Acknowledgement Type of funding source: None

A multiparametric ICD algorithm for heart failure risk stratification: an analysis in clinical practice

Abstract Purpose A novel multiparametric algorithm based on implantable cardioverter defibrillator (ICD) sensors has been recently developed. The HeartLogic index combines multiple parameters, i.e. heart sounds, intrathoracic impedance, respiration pattern, night heart rate, and patient activity, in a single index. In the validation study, the HeartLogic alert condition was shown to identify patients during periods of significantly increased risk of heart failure (HF) events. We sought to evaluate the risk stratification ability of the algorithm in a group of patients who received the system in clinical practice. Methods The HeartLogic feature was activated in 257 ICD and cardiac resynchronization therapy ICD patients (186 male, 70±11 years, left ventricular ejection fraction 30±8%) at 11 centers. The median follow-up duration was 14 months [25–75 percentile: 7–19]. The HeartLogic algorithm automatically calculates a daily HF index and identifies periods in or out of an alert state relative to a configurable threshold (in this analysis set to 16). Results Patients experienced 40 HF hospitalizations requiring at least 1 overnight stay (0.14/patient-year) during the observation period (285 patient-years). The HeartLogic index crossed the threshold value 191 times in 105 patients. The time in the alert state was 27 patient-years, i.e. 9.5% of the total observation period. HF hospitalization rate while in alert was 0.96/patient-year and 0.05/patient-year while out of alert. The occurrence of ≥1 index crossing during follow-up was associated with the risk of HF hospitalization (odds ratio: 4.70, CI 95%: 1.79–12.4, p=0.002), independently from other baseline clinical variables. Conclusions Our analysis of data collected in clinical practice confirms that the multiparametric ICD algorithm is an independent predictor of higher risk of HF. In particular, it allows dynamic identification of time-intervals when patients are at significantly increased risk of worsening HF. This potentially helps better triage resources to a more vulnerable patient population. Funding Acknowledgement Type of funding source: None

855Performance of a multisensor icd algorithm in heart failure patient management

Abstract Funding Acknowledgements No funding Background The HeartLogic index combines data from multiple implantable cardioverter-defibrillator (ICD)-based sensors and has proved to be a sensitive and timely predictor of impending heart failure (HF) decompensation. Purpose To describe a multicenter experience of remote HF management of patients who received a HeartLogic-enabled ICD or cardiac resynchronization therapy ICD (CRT-D). Methods The HeartLogic feature was activated in 104 patients (76 male, 71 ± 10 years, left ventricular ejection fraction 29 ± 7%). In accordance with a standardized follow-up protocol, remote data reviews and patient phone contacts were performed monthly and at the time of HeartLogic alerts (when the index crossed the nominal threshold value of 16), to assess the patient decompensation status. In-office visits were performed every 6 months or when deemed necessary. Results During a median follow-up of 13[11-18] months, 100 HeartLogic alerts were reported (0.82 alerts/pt-year) in 53 patients. 60 HeartLogic alerts were judged clinically meaningful (i.e. associated with worsening of HF or resulted in active clinical actions). Specifically, multiple associated conditions were reported: 45 (75%) symptoms or signs of clinical deterioration of HF, 13 (22%) discontinuations or reductions of prescribed HF therapy, 11 (18%) declines in CRT percentage (with or without new onset atrial fibrillation), 8 (13%) recurrences of previous HF events. For 48 out of 60 alerts the clinician was not previously aware of the condition. Of these, 43 alerts triggered multiple clinical actions. Alert-triggered actions were: 30 (70%) diuretic dosage increases, 15 (35%) other drug adjustments, 6 (14%) HF hospitalizations, 3 (7%) device reprogramming/revisions, 1 (2%) cardioversion, 1 (2%) patient education on therapy adherence. Out of 40 non-clinically meaningful alerts (0.33 alerts/pt-year), 8 (20%) were associated with non-HF therapy changes or interventions, 3 (8%) with pulmonary events, 29 (72%) remained unexplained. The overall number of HF hospitalizations was 16 (rate 0.13 hospitalizations/pt-year). Five HF hospitalizations were not preceded by HeartLogic alert (0.04 hospitalizations/pt-year). Conclusions The HeartLogic index provided clinically meaningful information and allowed to remotely identify relevant HF related clinical conditions, with a low rate of unexplained detections and undetected HF events. In this experience, remote monitoring using HeartLogic alerts allowed to drive HF care and take effective clinical actions.

Infection and migration incidence of cardiac implantable electrical devices in Japan: Web-based survey results.

Web‐based survey was conducted for experiences of cardiac implantable electrical device (CIED) infection and migration in Japan. A total of 155 cardiologists’ answer was collected in January, 2018. CIED includes pacemaker (PM), implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy pacemaker (CRT‐P), and cardiac resynchronization therapy ICD (CRT‐D) and total of 10,499 CIEDs’ experiences of within previous twelve months were reported. CIED includes pacemaker (PM), implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy pacemaker (CRT‐P), and cardiac resynchronization therapy ICD (CRT‐D.). The infection rate of PM, ICD, CRT‐P, and CRT‐D was 0.79%, 0.81%, 0.45%, and 2.0%, respectively, and the device migration rate was 0.68%, 0.64%, 0.45%, and 0.93%, respectively. The overall infection rate was 0.85% and migration rate was 0.68%.

P2872Remote management of heart failure patients with the multisensor ICD alert: preliminary results from the Italian pilot experience

Abstract Background The HeartLogic (Boston Scientific) index combines data from multiple implantable cardioverter-defibrillator (ICD)-based sensors and has proved to be a sensitive and timely predictor of impending heart failure (HF) decompensation. Objective To describe a preliminary experience of remote HF management of patients who received a HeartLogic-enabled ICD or cardiac resynchronization therapy ICD (CRT-D) in clinical practice. Methods The HeartLogic feature was activated in 101 patients (74 male, 71±10 years, ejection fraction 30±7%). From implantation to activation (blinded phase), the HeartLogic index trend was not available, thus no clinical actions were taken in response to it. After activation (active phase), remote data reviews and patient phone contacts were performed monthly and at the time of HeartLogic alerts (when the index crossed the nominal alert threshold value of 16), to assess the patient decompensation status. In-office visits were performed when deemed necessary. Results During the blinded phase, the HeartLogic index crossed the threshold value 24 times (over 24 person-years, 0.99 alerts/pt-year) in 16 patients. HeartLogic alerts preceded all hospitalizations and unplanned in-office visits for HF (sensitivity: 100%, median early warning: 38 days for hospitalizations, 12 days for HF visits). No clinical events were detected during or within 30 days of recovery of 10 HeartLogic alerts (unexplained alert rate: 0.41 per patient-year). Thus, the positive predictive value was 58% (14/24). During the active phase, 44 HeartLogic alerts were reported (over 46 person-years, 0.95 alerts/pt-year) in 30 patients. 26 (59%) HeartLogic alerts were judged clinically meaningful (i.e. associated with worsening of HF and/or influenced the clinician's decision to make changes to the subject's management). Conclusions In this first description of the use of HeartLogic in clinical practice, the algorithm demonstrated its ability to detect gradual worsening of HF. The results of the blinded phase of our experience favorably compare with those reported in the validation study. In the active phase, the HeartLogic index provided clinically meaningful information for the remote management of HF patients.

Preliminary experience with the multisensor HeartLogic algorithm for heart failure monitoring: a retrospective case series report.

AimsIn the Multisensor Chronic Evaluation in Ambulatory Heart Failure Patients study, a novel algorithm for heart failure (HF) monitoring was implemented. The HeartLogic (Boston Scientific) index combines data from multiple implantable cardioverter defibrillator (ICD)‐based sensors and has proved to be a sensitive and timely predictor of impending HF decompensation. The remote monitoring of HF patients by means of HeartLogic has never been described in clinical practice. We report post‐implantation data collected from sensors, the combined index, and their association with clinical events during follow‐up in a group of patients who received a HeartLogic‐enabled device in clinical practice.Methods and resultsPatients with ICD and cardiac resynchronization therapy ICD were remotely monitored. In December 2017, the HeartLogic feature was activated on the remote monitoring platform, and multiple ICD‐based sensor data collected since device implantation were made available: HeartLogic index, heart rate, heart sounds, thoracic impedance, respiration, and activity. Their association with clinical events was retrospectively analysed. Data from 58 patients were analysed. During a mean follow‐up of 5 ± 3 months, the HeartLogic index crossed the threshold value (set by default to 16) 24 times (over 24 person‐years, 0.99 alerts/patient‐year) in 16 patients. HeartLogic alerts preceded five HF hospitalizations and five unplanned in‐office visits for HF. Symptoms or signs of HF were also reported at the time of five scheduled visits. The median early warning time and the time spent in alert were longer in the case of hospitalizations than in the case of minor events of clinical deterioration of HF. HeartLogic contributing sensors detected changes in heart sound amplitude (increased third sound and decreased first sound) in all cases of alerts. Patients with HeartLogic alerts during the observation period had higher New York Heart Association class (P = 0.025) and lower ejection fraction (P = 0.016) at the time of activation.ConclusionsOur retrospective analysis indicates that the HeartLogic algorithm might be useful to detect gradual worsening of HF and to stratify risk of HF decompensation.

Cardiac resynchronization therapy pacemakers versus defibrillators in older non-ischemic cardiomyopathy patients

IntroductionWith the recent publication of the negative DANISH trial, the mortality benefit of the implantable cardioverter-defibrillator (ICD) has been put in question in patients with non-ischemic cardiomyopathy (NICM). Because a majority of patients in DANISH receive cardiac resynchronization therapy (CRT) devices, we investigated in the present study the survival of recipients of CRT pacemakers (CRT-P) versus CRT ICDs (CRT-D) in a cohort of older (≥75 years) NICM patients at our institution. MethodsA total of 135 NICM patients with CRT device were identified (42 with CRT-P and 93 with CRT-D) and were followed to the endpoint of all-cause mortality. Overall survival was compared between the CRT-P and CRT-D groups with adjustment for differences in baseline characteristics. ResultsOver a median follow-up of 46 months from the time of CRT device implantation, there were 54 total deaths (40%): 14 in the CRT-P (33%) and 40 in the CRT-D (43%) groups. Overall, CRT-P recipients had similar unadjusted mortality compared to CRT-D recipients (hazard ratio [HR] 1.04, 95% confidence interval [CI] 0.56–1.93), and this remained unchanged after adjusting for unbalanced covariates (HR 0.95, 95% CI 0.47–1.89) including left ventricular ejection fraction, used of angiotensin converting enzyme inhibitors/angiotensin receptor blockers, and the Charlson comorbidity index. ConclusionOur data support that in older NICM patients with CRT devices, the addition of ICD therapy does not improve survival.

Prospective Randomized Evaluation of Implantable Cardioverter‐Defibrillator Programming in Patients With a Left Ventricular Assist Device

BackgroundVentricular arrhythmias are common in patients with left ventricular assist devices (LVADs) but are often hemodynamically tolerated. Optimal implantable cardioverter defibrillator (ICD) tachy‐programming strategies in patients with LVAD have not been determined. We sought to determine if an ultra‐conservative ICD programming strategy in patients with LVAD affects ICD shocks.Methods and ResultsAdult patients with an existing ICD undergoing continuous flow LVAD implantation were randomized to standard ICD programming by their treating physician or an ultra‐conservative ICD programming strategy utilizing maximal allowable intervals to detection in the ventricular fibrillation and ventricular tachycardia zones with use of ATP. Patients with cardiac resynchronization therapy (CRT) devices were also randomized to CRT ON or OFF. Patients were followed a minimum of 6 months. The primary outcome was time to first ICD shock. Among the 83 patients studied, we found no statistically significant difference in time to first ICD shock or total ICD shocks between groups. In the ultra‐conservative group 16% of patients experienced at least one shock compared with 21% in the control group (P=0.66). There was no difference in mortality, arrhythmic hospitalization, or hospitalization for heart failure. In the 41 patients with CRT ICDs fewer shocks were observed with CRT‐ON but this was not statistically significant: 10% of patients with CRT‐ON (n=21) versus 38% with CRT‐OFF (n=20) received shocks (P=0.08).ConclusionsAn ultra‐conservative programming strategy did not reduce ICD shocks. Programming restrictions on ventricular tachycardia and ventricular fibrillation zone therapy should be reconsidered for the LVAD population. The role of CRT in patients with LVAD warrants further investigation.Clinical Trial RegistrationURL: https://www.clinicaltrials.gov. Unique identifier: NCT01977703.

Initial Clinical Experience With a New Automated Antitachycardia Pacing Algorithm: Feasibility and Safety in an Ambulatory Patient Cohort.

Antitachycardia pacing (ATP) in implantable cardioverter-defibrillators (ICD) decreases patient shock burden but has recognized limitations. A new automated ATP (AATP) based on electrophysiological first principles was designed. The study objective was to assess the feasibility and safety of AATP in ambulatory ICD patients. Enrolled patients had dual chamber or cardiac resynchronization therapy ICDs, history of ≥1 ICD-treated ventricular tachycardias (VT)/ventricular fibrillation episode, or a recorded, sustained monomorphic VT. Detection was set to ventricular fibrillation number of intervals to detect=24/32, VT number of intervals to detect≥16, and a fast VT zone of 240 to 320 ms. AATP prescribed the components and delivery of successive ATP sequences in real time, using the same settings for all patients. ICD datalogs were uploaded every ≈3 months, at unscheduled visits, exit, and death. Episodes and adverse events were adjudicated by separate committees. Results were adjusted (generalized estimating equations) for multiple episodes. AATP was downloaded into the ICDs of 144 patients (121 men), aged 67.4±11.9 years, left ventricular ejection fraction 33.1±13.6% (n=137), and treated 1626 episodes in 49 patients during 14.5±5.1 months of follow-up. Datalogs permitted adjudication of 702 episodes, including 669 sustained monomorphic VT, 20 polymorphic VT, 10 supraventricular tachycardia, and 3 malsensing episodes. AATP terminated 39 of 69 (59% adjusted) sustained monomorphic VT in the fast VT zone, 509 of 590 (85% adjusted) in the VT zone, and 6 of 10 in the ventricular fibrillation zone. No supraventricular tachycardias converted to VT or ventricular fibrillation. No anomalous AATP behavior was observed. The new AATP algorithm safely generated ATP sequences and controlled therapy progression in all zones without need for individualized programing.

Efficacy of implantable cardioconverter defibrillator or cardiac resynchronization therapy compared with combined therapy in survival of patients with heart failure: a meta-analysis.

The aim of this meta-analysis was to compare the efficacy of implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) monotherapies with CRT–ICD combined therapy.Databases were searched to identify studies that compared CRT or ICD alone with CRT–ICD combined therapy in patients with heart failure. The primary outcome was rate of death for any cause, and secondary outcomes included rate of death or hospitalization due to heart failure or any cause.Nine studies with 7679 patients were included. Combined data of ICD and CRT monotherapies found that there was a higher risk of all-cause death (odds ratio [OR] 1.348, P < 0.001) and death or hospitalization from heart failure (OR 1.368, P < 0.001) with monotherapy compared with CRT–ICD combined therapy. No significant difference was observed between mono and combined therapy groups for risk of death or hospitalization from any cause (OR 1.292, P = 0.083).Compared with ICD or CRT monotherapy, CRT–ICD therapy had favorable outcomes regarding all-cause death and the risk of hospitalization or death due to heart failure.

Abstract 9923: The Ethics of Unilateral ICD and CRT-D Deactivation: Patient Perspectives

Background: Decisions about deactivation of implantable cardioverter defibrillators (ICDs) are complicated. Unilateral Do-Not-Resuscitate (DNR) orders (against patient/family wishes) have been ethically justified in cases of medical futility. Unilateral deactivation of ICDs may be seen as a logical extension of a unilateral DNR order. Methods: 60 respondents who had an ICD or cardiac resynchronization therapy ICD (CRT-D) were interviewed at a quaternary medical center outpatient electrophysiology practice. Survey questions addressed the inclusion of ICD deactivation in advanced directives, whether ICD deactivation constitutes physician-assisted suicide, and whether unilateral ICD deactivation can be ethically justified. The average age was 59 (range 23-89), and 70% were male. Of the respondents, 35% had ICDs, and 65% had CRT-Ds. Respondents had had their devices for an average of 6.74 years (range 0.11-25). 82% of respondents were Caucasian, 15% were African American and 3% were Hispanic. Results: Only 15% of patients had thought about device deactivation if they were to develop a serious illness from which they were not expected to recover, and single respondents were more likely to have considered this point (38%, p=0.03). A small majority (53%) had advance directives, and only one mentioned what to do with the device. Only 3% had discussed device management with clinicians. Most (55%) believed turning off a patient’s pacemaker was no different than not performing CPR or administering external defibrillation. A majority (77%) did not consider device deactivation in accordance with patient wishes to be physician-assisted suicide. A majority (78%) responded that it was not ethical/moral for doctors to deactivate ICDs against patients’ wishes. Conclusion: In an era of cost-consciousness and scrutiny of resources, management of ICDs and CRT-Ds as patients near the end of their lives create ethical dilemmas. Few patients consider device deactivation at end of life, though a large majority believes that unilateral deactivation is not ethical or moral, even in the setting of medical futility. Advance care planning for these patients should address device deactivation.

Analysis of Different Device-Based Intrathoracic Impedance Vectors for Detection of Heart Failure Events (from the Detect Fluid Early from Intrathoracic Impedance Monitoring Study)

Detect Fluid Early from Intrathoracic Impedance Monitoring (DEFEAT-PE) is a prospective, multicenter study of multiple intrathoracic impedance vectors to detect pulmonary congestion (PC) events. Changes in intrathoracic impedance between the right ventricular (RV) coil and device can (RVcoil→Can) of implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy ICDs (CRT-Ds) are used clinically for the detection of PC events, but other impedance vectors and algorithms have not been studied prospectively. An initial 75-patient study was used to derive optimal impedance vectors to detect PC events, with 2 vector combinations selected for prospective analysis in DEFEAT-PE (ICD vectors: RVring→Can + RVcoil→Can, detection threshold 13 days; CRT-D vectors: left ventricular ring→Can + RVcoil→Can, detection threshold 14 days). Impedance changes were considered true positive if detected <30 days before an adjudicated PC event. One hundred sixty-two patients were enrolled (80 with ICDs and 82 with CRT-Ds), all with ≥1 previous PC event. One hundred forty-four patients provided study data, with 214 patient-years of follow-up and 139 PC events. Sensitivity for PC events of the prespecified algorithms was as follows: ICD: sensitivity 32.3%, false-positive rate 1.28 per patient-year; CRT-D: sensitivity 32.4%, false-positive rate 1.66 per patient-year. An alternative algorithm, ultimately approved by the US Food and Drug Administration (RVring→Can + RVcoil→Can, detection threshold 14 days), resulted in (for all patients) sensitivity of 21.6% and a false-positive rate of 0.9 per patient-year. The CRT-D thoracic impedance vector algorithm selected in the derivation study was not superior to the ICD algorithm RVring→Can + RVcoil→Can when studied prospectively. In conclusion, to achieve an acceptably low false-positive rate, the intrathoracic impedance algorithms studied in DEFEAT-PE resulted in low sensitivity for the prediction of heart failure events.

Normalization of Left Ventricular Ejection Fraction after Cardiac Resynchronization Therapy Also Normalizes Survival

Earlier studies in patients with reduced left ventricular ejection fraction (LVEF) ≤35% and prolonged QRS showed better survival outcomes with cardiac resynchronization therapy (CRT). Some patients respond dramatically to CRT by improving their LVEF to the normal range and are considered "super-responders." Our aim was to determine whether super-responders survival increases to levels comparable to the general population. We compared the survival of super-responders to the general population matched for age and sex. Of 909 patients with CRT device implantation between September 1998 and July 2008, 814 patients had pre- and post-CRT echocardiogram. A total of 95 patients with LVEF ≥ 50% following CRT were classified as super-responders. For 92 super-responders, who had U.S. Social Security numbers, an age- and sex-matched example was selected from the Social Security Life Tables. An expected survival plot of the matched population was then compared to the actual survival of super-responders. Super-responders had comparable survival to the age-sex matched general population (P = 0.53), and Kaplan-Meier survival analysis in 92 patients showed that super-responders with CRT pacemakers had similar survival to those with CRT implantable cardioverter defibrillators (P = 0.77). Super-responders were more likely to be females (54% vs 25%, P < 0.001) and less likely to have significant coronary artery disease (62% vs 42%, P < 0.001). Normalization of LVEF by CRT improves survival to levels comparable to the general population. This observation favors the concept that some CRT candidates have a cardiomyopathy likely generated by the conduction abnormality that is reversible through biventricular pacing.

Real‐World Data on the Lifespan of Implantable Cardioverter‐Defibrillators Depending on Manufacturers and the Amount of Ventricular Pacing

Implantable cardioverter-defibrillator (ICD) longevity is crucial for both patients and public health systems because it determines the number of surgical ICD replacements, which can generally be considered an additional risk factor for complications, and the cost-effectiveness of ICD therapy. Our objective was to obtain insight into the "real-world" longevities of implantable cardioverter-defibrillators, which quite often differ from those stated in the manufacturers' declarations. On the basis of a prospective database, we analyzed all ICD implantations performed in our hospital from June 1988 to June 2009. We studied 980 patients (follow-up 58 ± 51 months) with 1,502 ICDs and all respective data until August 2010. We compared the percentage of still operating ICDs at different points in time in relation to manufacturers, types of device (single chamber 623, dual chamber 588, cardiac resynchronization therapy ICDs [CRT-D] 291), and amount of right ventricular pacing (VP). We found distinct differences between the mean lifespans of ICDs of different manufacturers (Biotronik 4.3 years, Sorin 4.5 years, Guidant/Boston Scientific 4.7 years, St. Jude Medical 5 years, Medtronic 5.8 years). CRT-D devices (hazard ratio [HR] 1.778, P = 0.0005) were associated with an elevated annual relative risk for device replacement while a decrease in the proportion of VP (HR 0.934 for each 10% decrease in VP, P < 0.0001) and Medtronic ICDs were associated with a reduced risk of device replacement (HR 0.544, P < 0.0001). CRT-Ds and an elevated percentage of VP are associated with a significantly elevated risk for device replacement, while Medtronic ICDs showed the longest lifespans.

Electrogram-Based Optimal Atrioventricular and Interventricular Delays of Cardiac Resynchronization Change Individually During Exercise

Background Limited data suggest that optimal atrioventricular (AV) and interventricular (VV) delays are different at rest than during exercise in patients with heart failure. We assessed the feasibility and reproducibility of an electrogram-based method of optimization called QuickOpt at rest and during exercise. Methods Patients with a St Jude Medical cardiac resynchronization therapy implantable cardioverter-defibrillator were subjected to a graded treadmill test, and QuickOpt was repeatedly measured prior to, during, and after the exercise. Results Twenty-four patients (16 males, aged 67.4 ± 7.7 years) participated. At rest, delays (in ms) were 110.4 ± 20.1 for sensed AV delay and –70 (LV pacing first) to +20 (RV pacing first) for VV delay. The changes in QuickOpt-derived delays at rest were not significant despite change in body position. During exercise, QuickOpt-derived AV delays did not change in 11 patients, were shorter during peak exercise in 8 patients, and were longer in 3 patients (average value during peak exercise was 126.5 ± 15.8 ms, P = 0.04 compared to baseline). The QuickOpt-derived VV delay gradually shifted toward earlier right ventricular pacing during exercise in 19 patients, while no changes were seen in 3 patients, and a shift occurred toward earlier left ventricular pacing in 2 patients (average value during peak exercise was –30.7 ± 22.2; P = 0.001 compared to baseline). There was no correlation between changes in the QuickOpt-derived AV and VV delays and heart rate. Conclusions The application of electrogram-based algorithm is feasible both at rest and during exercise. The results are reproducible. QuickOpt-derived AV and VV delays individually change during exercise.

Selecting Patients for ICD Implantation

LARGE-SCALE REGISTRIES PROVIDE AN IMPORTANT WINdow into how medicine is actually practiced. In this issue of JAMA, Al-Khatib et al examined the National Cardiovascular Data Registry’s (NCDR’s) Implantable Cardioverter-Defibrillator (ICD) Registry to determine how often ICD implantations were performed in patients who did not meet criteria suggested in current guidelines for ICD use; specifically, ICD implantation within 40 days of an acute myocardial infarction (MI) or within 3 months of coronary artery bypass graft (CABG) surgery, recent diagnosis of congestive heart failure (CHF), and presence of New York Heart Association (NYHA) class IV symptoms. AlKhatib et al found that almost one-quarter of ICD implantations were performed in patients with these characteristics, mortality and complication rates were higher among these patients than for patients who received an ICD based on evidence-based guidelines, and nonelectrophysiologists performed non–guideline-based ICD implantations with a higher frequency than electrophysiologists. These findings should be used to inform public health policies toward the appropriate use of this life-saving but expensive technology. The first question that needs to be addressed involves the reliability of the data. The ICD Registry is a well-audited tool that is robust and provides important information. Its strengths lie in the large number of patients included in the registry and in the quality of the data monitoring process. Nonetheless, some variables in the registry may not be accurate. For example, more physicians self-reported being board-certified electrophysiologists in the ICD Registry than have actually been board certified. In addition, the largest group of patients who received non–evidence-based ICDs in the report by Al-Khatib et al were those with a recent diagnosis of CHF. In most cases, ICD Registry data are retrospectively abstracted from the medical record by nurses or other health care professionals. The precise onset of CHF may not be well documented in the medical record because unlike the date of MI, evaluating the date of diagnosis of CHF may require a history that is targeted to this variable. The data abstractor may find evidence of CHF based on a recent hospitalization, but a thorough history could identify a much earlier onset. Even though these issues may affect some of the quantitative findings, the qualitative findings from this report are not likely to be affected significantly, particularly given the large size of the registry. Is it appropriate to implant ICDs for patients who do not meet specific criteria recommended in the guidelines? The authors note that there are circumstances in which deviations from guidelines are appropriate based on the physician’s judgment. Accordingly, while there will be some background rate of ICD implantation outside of guideline recommendations, it is unclear what this background rate should be. As shown in Figure 1 of the article by Al-Khatib et al, only a very small number of sites had a non–guidelinebased ICD implantation rate of less than 6%, suggesting this might be a reasonable lower bound. The upper bound is more difficult to determine, but should be less than the 21% rate of non–guideline-based ICD implantation noted among cardiac electrophysiologists. Moreover, for 3 of the 4 indications Al-Khatib et al classified as non–evidence-based ICD implantation, the issue is timing of the ICD implantation. For instance, a valid medical concern would be that a patient who recently experienced an MI, underwent CABG surgery, or was diagnosed with CHF is at high-risk for sudden death during the waiting period that is indicated in the guidelines. However, no data are available in the NCDR’s ICD Registry regarding this assessment or whether alternative approaches such as the use of the wearable cardioverter-defibrillator were considered. In addition, while there are convincing data that early implantation of an ICD after an MI does not improve outcomes, the data may be less convincing for other conditions. One post hoc analysis, although not definitive, has shown that some patients with nonischemic cardiomyopathy may benefit from early ICD implantation. However, the use of non–cardiac resynchronization therapy ICDs in patients with NYHA class IV symptoms is unwarranted. The other critical findings of this study were the higher rates of non–guideline-based ICD implantation performed by nonelectrophysiologists (cardiologists, thoracic sur-