Cardiac Resynchronization Therapy Defibrillator Research Articles

PO-04-049 PATIENT CHARACTERISTICS AND FIVE-YEAR CLINICAL OUTCOMES OF PATIENTS WITH HEART FAILURE WITH MID-RANGE EJECTION FRACTION.

Clinical outcomes of patients presenting with heart failure and mid-range ejection fraction (HFmEF) between 35-50% is less defined. Cardiac risk factors are associated with increased risk of disease progression. To define patient clinical characteristics associated with worsening and improvement in cardiac function and clinical outcomes. Between July 2017 and December 2022, 250 patients (pts) were identified with newly diagnosed heart failure with HFmEF. Clinical characteristics, comorbidities, outcomes and prognosis among these pts who improved (Group-1: left ventricular ejection fraction (LVEF) >50%) remain stable (Group-2: LVEF 35-50%) and worsened (Group-3: LVEF <35%) were analysed. At a mean follow up of 55±6 months, LVEF improved in 146 (58.4%) pts, 69 pts (27.6%) remained stable and 35pts (14%) worsened. All pts were started on guideline directed optimal heart failure medication. At final follow up, in group 1, 9 (6.16%) had sustained Ventricular Arrhythmias VAs, none were hemodynamically significant VA, 8 (5.48%) needed ICD and 1 (0.68%) needed CRTD. Group 2, 16 (23.18%) had sustained VAs, 1 (1.45%) hemodynamically significant VA, 12 (17.39%) needed ICD and 4 (5.79%) needed CRTD. Group 3, 21 (60%) had sustained VAs, 5 (14.28%) hemodynamically significant VA, 16 (45.71%) needed implantable cardioverter defibrillator (ICD) and 5 (14.28%) needed cardiac resynchronisation therapy defibrillator (CRTD). Table 1 shows clinical characteristics of the three distinct subgroups and clinical outcomes. Mid-range cardiomyopathy is not a benign condition. Aggressive targeted treatment strategies should be embarked to improve outcomes. Careful monitoring and routine follow up needs to be undertaken. Diabetes, CAD, scar at baseline on MRI and VAs are adverse predictors of left ventricular function improvement and prognosis.

PO-03-054 OPTIMIZING REMOTE MONITORING ALERTS FOR CIED PATIENTS TO REDUCE RESOURCE UTILIZATION WITHOUT COMPROMISING CLINICAL CARE

The benefits of remote monitoring (RM) have been demonstrated in multiple clinical studies and have become the standard of care for patients with cardiovascular implantable electronic devices (CIEDs). Benefits include fewer hospitalizations, reduction in mortality and improved clinical workflow by reducing in-office visits. As RM utilization increases, the amount of transmitted data can become a resource burden for responsible caregivers. To evaluate RM alert burden from actively monitored CIED patients within US-based integrated healthcare system to identify opportunities to optimize RM and a reduction of provider workload. We conducted an epidemiologic descriptive study using data from 9,781 CIED Patients from 7 healthcare centers within Kaiser Permanent who were monitored using BIOTRONIK Home Monitoring® (HM) from 1/1/22 through 7/31/22. Frequencies and proportions were used to describe alerts during the study period, as well as occurrence by device type. Patterns were identified that suggest specific alert programming differences leading to unnecessary alerts from a given healthcare centers or device type. In total, 9,781 active CIED patients enrolled in HM were analyzed. A total of 8,519 (87%) patients had ≥1 alert in the given timeframe. The distribution of device types in the patient population with an alert was: 5,725 (67%) implantable pulse generator (IPG), 132 (2%) cardiac resynchronization therapy pacemaker (CRT-P), 1,718 (20%) implantable cardioverter-defibrillator (ICD), 715 (8%) cardiac resynchronization therapy defibrillator (CRT-D) and 229 (3%) implantable cardiac monitors (ICM). A breakdown of alerts per patient per month shows that the majority (65%) of all alerts are generated by a minority of patients (20%). In conjunction with this finding, the alert per patient rate in this timeframe was the highest for ICM (15/patient) and CRT-D (13/patient) which represents 10% of all patients. Alert optimization is essential to reduce the work burden associated with RM. As shown in this analysis a limited number of patients (20%) are responsible for a significant portion of the overall alert burden (65%). We plan to target those high-volume alert sites as well as the specific alerts and specific patients to create server-based alert “templates” to optimize patient care and decrease alert burden for clinicians. A subsequent analysis will determine impact on patient outcomes and reduction in the burden of work.

PO-05-009 SAFETY OF MAGNETIC RESONANCE IMAGING IN PATIENTS WITH SURGICALLY IMPLANTED PERMANENT EPICARDIAL LEADS

Magnetic resonance imaging (MRI) safety in patients with an epicardial cardiac implantable electronic device (CIED) is uncertain. To assess the safety and adverse effects of MRI in patients who had surgically implanted epicardial CIED. Patients with surgically implanted CIEDs who underwent MRI between January 2008 and January 2021 were prospectively studied in two clinical centers. All patients underwent close cardiac monitoring through MRI procedures. Outcomes were compared between the epicardial CIED group and matched transvenous CIED group. Twenty-nine consecutive patients with epicardial CIED (male 41.4%, mean age of 43 years) underwent 52 MRIs in the 57 anatomic regions. Sixteen patients had pacemakers, 9 had cardiac defibrillators or cardiac resynchronization therapy defibrillators, and 4 had no device generators. There were no significant adverse events in epicardial or transvenous CIED groups. The battery life, pacing, sensing thresholds, lead impedance and cardiac biomarkers were not significantly changed, except one patient had a transient decrease in atrial lead sensing function. MRI of CIEDs with epicardially implanted leads does not represent a greater risk than the transvenous CIEDs.

PO-03-076 MACHINE LEARNING METHODS IDENTIFYING RISK FOR 30-DAY HEART FAILURE READMISSION USING DIAGNOSTICS PARAMETERS FROM IMPLANTED CARDIOVASCULAR DEVICES

Heart failure (HF) related diagnostics parameters measured daily from implantable cardioverter defibrillators (ICD) and cardiac resynchronization therapy defibrillators (CRTD) have shown to change before, during and after HF hospitalization events. We assessed the ability to identify patients at risk of a recurrent HF admission with different machine learning techniques leveraging statistical and temporal behavior of the cardiac compass parameters prior and during HF hospitalization events. We linked Optum® deidentified Electronic Health Record dataset during the period from 2007-2021 to the Medtronic CareLinkTM data warehouse with device based continuous diagnostic monitoring data. Patients with ICD/CRTD implants with intra-thoracic impedance diagnostic feature were included for this study. Retrospective analysis was completed identifying HF admissions with diagnostic parameters from 30-days prior admission day ending on discharge day. Analyzed events included such HF admissions within the 2 to 30 days for length of stay. Admission day parameters were evaluated with the following criteria: 7-days to 30-days activity, night heart rate and day heart rate ratios, plus 3-day impedance change. In addition, diagnostic data during hospitalization was summarized into range, median, mean, and standard deviation. Length of stay was also used as an input for the models. Two groups were created based on hospitalization events with or without 30-day readmission. Dataset was split into training and validation subsets. Multiple machine learning models were trained to classify events indicating those followed by a close HF readmission. Models’ results were compared in terms of sensitivity, specificity, and false positive rates on validation set. 1745 HF hospitalization events were assessed in this study, including 486 preceding a re-admission event within 30-days post discharge. The average length of stay on this cohort was 6.2 days. Seven machine learning models were trained using 28 features derived from diagnostic data and length of stay as input. Models’ sensitivity and specificity ranged from 0.11 to 0.84 and 0.89 to 0.93 respectively. Table 1 depicts area under the curve (AUC) for each trained model. Mean model accuracy on validation data was 0.84. A machine learning derived HF diagnostic criteria evaluating diagnostic parameters on HF admission day plus while in hospital may be useful to identify patients at higher risk of 30-days HF readmission at time of discharge.Tabled 1Table 1. AUC for each Classification ModelMODEL NAMEAUCLogistic Regression0.92Decision Tree0.82RUSBoosted Trees0.94Support Vector Machine0.83Bi-layered Neural Network0.86Three-layered Neural Network0.86Optimizable Neural Network0.94 Open table in a new tab

MP-453089-9 OUTCOMES WITH GUIDELINE-DIRECTED MEDICAL THERAPY AND CARDIAC IMPLANTABLE ELECTRONIC DEVICE THERAPIES FOR PATIENTS WITH HEART FAILURE WITH REDUCED EJECTION FRACTION

Foundational guideline-directed medical therapy (GDMT) for heart failure (HF) with reduced ejection fraction (HFrEF) now consists of 4 classes. There is limited real-world evidence for outcomes associated with GDMT or GDMT with cardiac implantable electronic device therapies (here, implantable cardiac defibrillators [ICDs]/cardiac resynchronization therapy defibrillators [CRT-Ds]). The present study assessed outcomes associated with GDMT or GDMT with ICD/CRT-D for patients with HFrEF and left ventricular ejection fraction (LVEF) ≤35%. We analyzed patients (age ≥18 years) with HFrEF (LVEF ≤35%) in a deidentified real-world dataset including 5,218,134 patients from 20 US institutions with appropriate permissions (egnite Database; egnite, Aliso Viejo, CA, US). Treatment rates, LVEF improvement, and all-cause mortality were examined using unadjusted Kaplan–Meier analysis with first documented echocardiogram with LVEF ≤35% as index event. Mortality analysis used prescribed GDMT class count and device placement as time-varying covariates and censored patients at last clinical encounter. Treatment rate and LVEF improvement analysis censored patients at last clinical encounter/death. Of 362,693 patients with documented HF, 22,061 were included with LVEF ≤35%, prescription history through ≥1 year pre-index, and no device therapy pre-index. Median (IQR) time from index to censor/death was 13.5 (4.2–27.1) months. At index, 95.7%, 73.5%, 29.4%, and 3.5% of patients had ≥1, 2, 3, or all 4 GDMT classes prescribed, respectively. At 18 months, an estimated (95% CI) 98.7% (98.5–98.9%), 84.8% (84.5–85.1%), 43.2% (42.7–43.7%), and 8.1% (7.7–8.4%) had ≥1, 2, 3, or all 4 GDMT classes prescribed, respectively; an estimated 15.3% (14.7–15.9%) had device placement. Of those without a device, by 18 months, an estimated 39.1% (38.2–40.0%) had a documented LVEF >35%. Cohorts with a device and 2, 3, or 4 GDMT classes prescribed had estimated 18-month survival of 83.1% (79.2–87.2%), 85.4% (82.0–89.0%), or 88.9% (83.5–94.8%), respectively (Figure). There were insufficient data for analysis of those with a device and 0/1 GDMT classes. Cohorts without a device and 0, 1, 2, 3, or 4 GDMT classes prescribed had estimated 18-month survival of 70.8% (66.3–75.6%), 73.4% (71.7–75.2%), 77.8% (76.8–78.8%), 81.8% (80.7–82.9%), and 87.6% (85.4–89.9%), respectively (Figure). Higher counts of GDMT classes prescribed and device therapy with GDMT were associated with greater survival in this population.

PO-02-016 PHYSIOLOGIC SIGNALS FROM CRT DEVICES ARE INDICATIVE OF CRT RESPONSE IN SMART-MSP STUDY

Cardiac resynchronization therapy (CRT) is a well-established treatment for some heart failure patients with reduced ejection fraction, but a subset of these patients does not respond to CRT. Multi-site pacing (MSP) is proposed to improve clinical response to CRT, but it is unclear which CRT subset would benefit from MSP. Physiologic sensor data from CRT devices may provide insights into this question. To determine whether device based physiologic parameters are indicative of CRT response/non-response and thus identify potential candidates for MSP. SMART-MSP study evaluated 6-month CRT response, defined by improved Clinical Composite Score, in patients with CRT defibrillators (CRT-D). Device parameters considered for this analysis included third (S3) and first (S1) heart sounds, thoracic impedance (ITTI), respiration rate, rapid shallow breathing index (RSBI), activity, and the multi-sensor HeartLogic index. From a randomly selected 60% development set of patients (183 CRT responders and 40 non-responders) with at least 150 days of data, the following statistical measures were calculated for each parameter based on the first 60- and 150-day epoch after CRT-D implant: mean (μ), standard deviation (σ) and change from first 30-day mean to last 30-day mean (Δ). To evaluate the effect of each measure on CRT response, odds ratios were calculated and tested for significance via univariable and multivariable logistic regression. The 60-day analysis (Fig 1A) shows that increases in σ60 for S3, S3/S1, RSBI, respiration rate, and HeartLogic index as well as μ60 for RSBI were significantly associated with reduced odds of CRT response in the univariable model. The only signal to survive multivariate elimination was respiration rate σ60. The 150-day analysis (Fig 1B) shows the same indications and that increases in μ150 for RSBI and HeartLogic index were associated with reduced odds while increases in μ150 and Δ150 for activity were associated with increased odds of CRT response. Both respiration rate σ150 and activity Δ150 survived multivariate elimination. Multiple device-based physiologic parameters significantly differed between CRT responders versus non-responders in the SMART-MSP study. 60-day results indicate that there is potential for device-based parameters to identify patients who may benefit from switching to MSP sooner. However, while useful parameters are apparent early on (60-day window), more parameters become significant over a longer follow-up (150 days).

PO-03-043 IMPLANTABLE CARDIOVERTER DEFIBRILLATOR THERAPY WITH LEFT BUNDLE AREA PACING DELIVERS HIGHLY SUCCESSFUL ANTITACHYCARDIA PACING THERAPY FOR VENTRICULAR TACHYCARDIA AND SUCCESSFUL DEFIBIRILLATION

Left bundle area pacing (LBAP) has emerged as a promising therapy for cardiac resynchronization. However, the effects of LBAP when used as the primary sensing and antitachycardia pacing lead for implantable cardioverter defibrillator (ICD) therapy is unknown. There are potential disadvantages of using a separate pace/sense lead as the defibrillator lead integrity alerts are not maintained and dislodgement may not be known. Additionally, DF1 leads add complexity and points of failure to an ICD system. Examine the outcomes of using a LBAP lead as the pace/sense lead in ICD therapy. A retrospective review of all patients with implanted LBAP leads for ICD therapy was performed. In all cases a DF1 defibrillator lead was used with the pace/sense portion capped and a LBAP lead used. All devices were Abbott (Ellipse, Fortify, Quadra assura). In some cases simultaneous LBAP and CS pacing was performed. Medtronic 3830 leads were used for LBAP. Outcomes included VT events, ATP, and defibrillator therapy. Programming was left ot operator discretion but when no prior history of VT was known a monitor rate of 170 and treatment rate of 200 was programmed. 65 patients were identified with 45 ICDs and 20 cardiac resynchronization therapy defibrillators (CRTDs) since January of 2020. The median follow up time was 13 months. There were 138 VT/VF episodes during the study period occuring in 10 patients. 7 episodes were adjudicated to be SVT and 2 led to inappropriate shocks (1.5%). VT cycle length was 317±31 ms (rate: 191±17 bpm) withATP was delivered in 126 episodes and successfully terminated 120 (95%) of episodes. Per patient success was 90% with an average 1.3 ATP attempts. 5 appopriate shocks were delivered with 100% success. ICD therapy with a LBAP pacing lead as the primary pace/sense lead delivers highly effective ATP and ICD therapy. The rate of successful ATP is significantly higher than previous studies of ATP which have generally ranged from 50-70%. There are several plausible reasons for this including a more rapid and synchronous depolarization of the ventricle rendering more of the ventricle refractory. The small number of shocks were successful. There were no lead dislodgements or issues with sensing. These findings merit further study into the role of LBAP for ICD and ATP therapy.

PO-04-059 THORACIC DUCT LEAK AFTER DEFIBRILLATOR IMPLANTATION

Device implantation is a relatively low-risk procedure, however generator pocket complications can still occur. In this case, the device site was complicated by a thoracic duct chylous extravasation leading to lymphatic drainage into a device pocket. Case Report A 55-year-old male with ischemic congestive heart failure and reduced ejection fraction of 30-35% and left bundle branch block >150 milliseconds presented several months after cardiac resynchronization therapy-defibrillation (CRT-D) implantation with device site swelling. The physical exam was notable for an extremely swollen left arm consistent with lymphedema. This swelling slowly enlarged for the past 6 months after implantation. Concern was for device site complication with a slowly evolving hematoma that caused compressive lymph stasis. Decision was made for device extraction and reimplantation. Pictured below (Figure 1) shows that the device pocket actually was filled with lymphatic fluid. Upon further investigation, the thoracic duct was either damaged or obstructed and likely the culprit. The pocket was then evacuated with subsequent device extraction and reimplantation. No immediate complications were noted. Upon follow-up, the device site was normal, and left arm lymphedema was resolved. This case demonstrates a rare complication of device implantation that does not appear to be reported in our literature search. Typically hematoma, infection, erosion, migration, and Twiddler’s Syndrome are the most common complications in device pockets. The thoracic duct typically runs from the superior aspect of the cisterna chyli which is situated at the L2 vertebrae and runs to the lower cervical spine. Termination in 95% of patients are either the internal jugular vein, subclavian vein, or the angle between them. However, termination is typically posterior without a superficial course. Lymphatic obstruction tends to be late presenting and can be easily confused with venous obstruction leading to delays in care. Management of lymphatic drainage usually is removing the obstructive source, however, a low fat diet has shown benefit. Thoracic duct complications in device implantation are rare but can lead to delayed treatment and repeat procedures. Further investigation into such cases may be warranted.

MP-453089-1 DIGOXIN AND RISK OF VENTRICULAR TACHYARRHYTHMIA AND DEATH IN ICD RECIPIENTS

Digoxin continues to be used in patients with heart failure with reduced ejection fraction (HFrEF), especially among those with atrial fibrillation (AF) with difficult to control ventricular response. However, some studies have shown digoxin use to be associated with adverse outcomes including increased mortality. There are limited data on whether digoxin use is associated with increased risk of ventricular tachycardia/ventricular fibrillation (VT/VF) in implantable cardioverter defibrillator (ICD) recipients. We sought to assess whether digoxin use would be associated with increased risk of VT/VF in patients with HFrEF who were implanted with a primary prevention ICD in landmark clinical trials. Our study cohort consisted of patients with an ICD or cardiac resynchronization therapy-defibrillator (CRT-D) who were enrolled in the four landmark MADIT trials. Propensity score for digoxin at baseline was developed using a wide variety of baseline clinical measures with a logistic regression model stepwise variable selection approach. All potential variables which met a significance level <0.10 were included in the propensity score model. Additionally, a multivariate proportional hazards regression model was developed for the endpoint of VT/VF. This multivariate model was used along with propensity score quintile stratification for the endpoints of VT/VF, death and VT/VF/death. At baseline, 1155 of 4499 patients were on digoxin (26%). Propensity score variables are shown in Table 1. From statistical models using both multivariate adjustment and propensity score quintile stratification, patients prescribed digoxin exhibited a statistically significant 28% increased risk of VT/VF [HR 1.28 (1.10-1.50); p=0.002; Figure 1A], 38% increased risk of the composite of VT/VF or death [HR 1.38 (1.21-1.58); p<0.0001; Figure 1B]; and a 64% increased risk of death [HR 1.64; (1.32-2.04); p<0.0001]. Our findings suggest that digoxin use is associated with a significant increased risk of ventricular tachyarrhythmic events and death among ICD recipients. This adds to the growing evidence that digoxin use is associated with adverse outcomes in certain groups of patients and suggest a need for reconsideration on use of digoxin in HFrEF patients with an ICD.

Safety of magnetic resonance imaging in patients with surgically implanted permanent epicardial leads

Magnetic resonance imaging (MRI) safety in patients with an epicardial cardiac implantable electronic device (CIED) is uncertain. The purpose of this study was to assess the safety and adverse effects of MRI in patients who had surgically implanted epicardial CIED. Patients with surgically implanted CIEDs who underwent MRI with an appropriate cardiology-radiology collaborative protocol between January 2008 and January 2021 were prospectively studied in 2 clinical centers. All patients underwent close cardiac monitoring through MRI procedures. Outcomes were compared between the epicardial CIED group and the matched non-MRI-conditional transvenous CIED group. Twenty-nine consecutive patients with epicardial CIED (41.4% male; mean age 43 years) underwent 52 MRIs in 57 anatomic regions. Sixteen patients had a pacemaker, 9 had a cardiac defibrillator or cardiac resynchronization therapy-defibrillator, and 4 had no device generator. No significant adverse events occurred in the epicardial or transvenous CIED groups. Battery life, pacing, sensing thresholds, lead impedance, and cardiac biomarkers were not significantly changed, except 1 patient had a transient decrease in atrial lead sensing function. MRI of CIEDs with epicardially implanted leads does not represent a greater risk than transvenous CIEDs when performed with a multidisciplinary collaborative protocol centered on patient safety.

Leadless Pacing: Therapy, Challenges and Novelties.

Leadless pacing is a rapidly growing field. Initially designed to provide right ventricular pacing for those who were contraindicated for conventional devices, the technology is growing to explore the potential benefit of avoiding long-term transvenous leads in any patient who requires pacing. In this review, we first examine the safety and performance of leadless pacing devices. We then review the evidence for their use in special populations, such as patients with high risk of device infection, patients on haemodialysis, and patients with vasovagal syncope who represent a younger population who may wish to avoid transvenous pacing. We also summarise the evidence for leadless cardiac resynchronisation therapy and conduction system pacing and discuss the challenges of managing issues, such as system revisions, end of battery life and extractions. Finally, we discuss future directions in the field, such as completely leadless cardiac resynchronisation therapy-defibrillator devices and whether leadless pacing has the potential to become a first-line therapy in the near future.

Implantable defibrillator-detected heart failure status predicts ventricular tachyarrhythmias.

The prediction of ventricular tachyarrhythmias among patients with implantable cardioverter defibrillators is difficult with available clinical tools. We sought to assess whether in patients with heart failure (HF) and reduced ejection fraction with defibrillators, physiological sensor-based HF status, as summarized by the HeartLogic index, could predict appropriate device therapies. Five hundred and sixty-eight consecutive HF patients with defibrillators (n = 158, 28%) or cardiac resynchronization therapy-defibrillators (n = 410, 72%) were included in this prospective observational multicenter analysis. The association of both HeartLogic index and its physiological components with defibrillator shocks and overall appropriate therapies was assessed in regression and time-dependent Cox models. Over a follow-up of 25 (15-35) months, 122 (21%) patients received an appropriate device therapy (shock, n = 74, 13%), while the HeartLogic index crossed the threshold value (alert, HeartLogic ≥ 16) 1200 times (0.71 alerts/patient-year) in 370 (65%) subjects. The occurrence of ≥1 HeartLogic alert was significantly associated with both appropriate shocks (Hazard ratios [HR]: 2.44, 95% confidence interval [CI]: 1.49-3.97, p = .003), and any appropriate defibrillator therapies. In multivariable time-dependent Cox models, weekly IN-alert state was the strongest predictor of appropriate defibrillator shocks (HR: 2.94, 95% CI: 1.73-5.01, p < .001) and overall therapies. Compared with stable patients, patients with appropriate shocks had significantly higher values of HeartLogic index, third heart sound amplitude, and resting heart rate 30-60 days before device therapy. The HeartLogic index is an independent dynamic predictor of appropriate defibrillator therapies. The combined index and its individual physiological components change before the arrhythmic event occurs.

Performance of alert transmissions from cardiac implantable electronic devices to the CareLink network: A retrospective analysis

Remote monitoring of cardiac implantable electric devices improves patient outcomes and experiences. Alert-based systems notify physicians of clinical or device issues in near real-time, but their effectiveness is contingent upon device connectivity. To assess patient connectivity by analyzing alert transmission times from patient transceivers to the CareLink network. Alert transmissions were retrospectively gathered from a query of the United States de-identified Medtronic CareLink database. Alert transmission time was defined as the duration from alert occurrence to arrival at the CareLink network and was analyzed by device type, alert event, and alert type. Using data from previous studies, we computed the benefit of daily connectivity checks. The mean alert transmission time was 14.8 hours (median = 6 hours), with 90.9% of alert transmissions received within 24 hours. Implantable pulse generators (17.0 ± 40.2 hours) and cardiac resynchronization therapy-pacemakers (17.2 ± 42.5 hours) had longer alert transmission times than implantable cardioverter-defibrillators (13.7 ± 29.5 hours) and cardiac resynchronization therapy-defibrillators (13.5 ± 30.2 hours), but the median time was 6 hours for all 4 device types. There were differences in alert times between specific alert events. Based on our data and previous studies, daily connectivity checks could improve daily alert transmission success by 8.5% but would require up to nearly 800 additional hours of staff time on any given day. Alert transmission performance from Medtronic devices was satisfactory, with some delays likely underscored by patient connectivity issues. Daily connectivity checks could provide some improvement in transmission success at the expense of increased clinic burden.

Acute and long-term outcomes of quadripolar IS-4 versus bipolar IS-1 left ventricular leads in cardiac resynchronization therapy: A retrospective registry study.

The implantation procedure of left ventricular (LV) leads and the management of cardiac resynchronization therapy (CRT) patients can be challenging. The IS-4 standard for CRT offers additional pacing vectors compared to bipolar leads (IS-1). IS-4 leads improve procedural outcome and may also result in lower adverse events during follow-up (FU) and improve clinical outcome in CRT patients. Further long-term FU data comparing the two lead designs are necessary. In this retrospective, single-center study we included adult patients implanted with a CRT-Defibrillator (CRT-D) or CRT-Pacemaker (CRT-P) with a quadripolar (IS-4 group) or bipolar (IS-1 group) LV lead and with available ≥3 years clinical FU. The combined primary endpoint was a combination of predefined, lead-related adverse events. Secondary endpoints were all single components of the primary endpoint. Overall, 133 patients (IS-4 n = 66; IS-1 n = 67) with a mean FU of 4.03 ± 1.93 years were included. Lead-related adverse events were less frequent in patients with an IS-4 lead than with an IS-1 lead (n = 8, 12.1% vs. n = 23, 34.3%; p = .002). The secondary outcomes showed a lower rate of LV lead deactivation/explantation and LV lead dislodgement/dysfunction (4.5% vs. 22.4%; p = .003; 4.5% vs. 17.9%; p = .015, respectively) in the IS-4 patient group. Less patients suffered from unresolved phrenic nerve stimulation with an IS-4 lead (3.0% vs. 13.4%; p = .029). LV lead-related re-interventions were fewer in case of an IS-4 lead (6.1% vs. 17.9%; p = .036). In this retrospective analysis, the IS-4 LV lead is associated with lower lead-related complication rates than the IS-1 lead at long-term FU.

Long-term risk of cardiovascular implantable electronic device reinterventions following external cardioversion of atrial fibrillation and flutter: A nationwide cohort study

External cardioversion (ECV) is an essential part of rhythm control of atrial fibrillation and flutter in patients with and without cardiovascular implantable electronic devices (CIEDs). Long-term follow-up data on ECV-related CIED dysfunctions are limited. The purpose of this study was to investigate the risk of CIED reintervention following ECV in a nationwide cohort. We identified CIED implants and surgical reinterventions from 2005 to 2021 in the Danish Pacemaker and ICD Register. We included CIED patients undergoing ECV from 2010 to 2019 from the Danish National Patient Registry. For each ECV-exposed generator, 5 matched generators without ECV were identified, and for each ECV-exposed lead, 3 matched leads were identified. The primary endpoints were generator replacement and lead reintervention. We compared 2582 ECV-exposed patients with 12,910 matched patients with a pacemaker (47%), implantable cardioverter-defibrillator (ICD) (29%), cardiac resynchronization therapy-pacemaker (6%), or cardiac resynchronization therapy-defibrillator (18%). During 2 years of follow-up, 210 ECV-exposed generators (8.1%) vs 670 matched generators (5.2%) underwent replacements, and 247 ECV-exposed leads (5.6%) vs 306 matched leads (2.3%) underwent reintervention. Unadjusted hazard ratios were 1.61 (95% confidence interval [CI] 1.37-1.91; P <.001) for generator replacement and 2.39 (95% CI 2.01-2.85; P <.001) for lead reintervention. One-year relative risks were 1.73 (95% CI 1.41-2.12; P <.001) for generator replacement and 2.85 (95% CI 2.32-3.51; P <.001) for lead reintervention, and 2-year relative risks were 1.39 (95% CI 1.19-1.63; P <.001) and 2.18 (95% CI 1.84-2.57; P <.001), respectively. ECV in patients with a CIED is associated with a higher risk of generator replacement and lead reintervention. The risks of reinterventions were more pronounced within the first year after cardioversion.

Variation in hospital use of cardiac resynchronization therapy-defibrillator among eligible patients and association with clinical outcomes

Despite strong guideline recommendations for cardiac resynchronization therapy-defibrillator (CRT-D) in select patients, this therapy is underutilized with substantial variation among hospitals, and the association of this variation with outcomes is unknown. The purpose of this study was to assess whether facility variation in CRT-D utilization is associated with differences in hospital-level outcomes. We linked Medicare claims data with the National Cardiovascular Data Registry's ICD Registry from 2010 to 2015. We calculated the intraclass correlation coefficient to quantify the degree of variation in patient-level CRT use that can be explained by interfacility variation on a hospital level. To quantify the degree of hospital variation in patient-level outcomes (all-cause mortality, readmissions, and cardiac readmissions) that can be attributed to variations in CRT-D use, we utilized multilevel modeling. The study included 30,134 patients across 1377 hospitals. The median rate of CRT-D implantation in those meeting guideline indications was 89%, but there was a wide variation across hospitals. After adjustment, most of the variation (74%) in hospital rates of CRT-D utilization was attributable to the hospital in which the patient was treated. Differences in hospital CRT-D utilization was associated with 8.76%, 5.26%, and 4.71% of differences in hospital mortality, readmissions, and cardiac readmission rates, respectively (P < .001 for all outcomes). There is a wide variation in the use of CRT-D across hospitals that was not explained by case mix. Hospital-level variation in CRT-D utilization was associated with clinically significant differences in outcomes. A measure of CRT-D utilization in eligible patients may serve as a useful metric for quality improvement efforts.

Incidence and clinical predictors of early and late complications of implantable cardioverter-defibrillators in adults with congenital heart disease.

The Implantable cardioverter-defibrillator (ICD) has been proven to improve survival in adults with congenital heart disease (ACHD), however it is associated with a high rate of complications. We aimed to quantify the incidence of early (≤3 months) and late (>3 months) complications (EC, LC) in ACHD patients implanted with an ICD and identify their clinical predictors. We retrospectively reviewed 207 patients who had ICD follow-up at Toronto General Hospital between 1996 and 2019. Most common diagnoses were Tetralogy of Fallot (32.4%), dextro-transposition of the great arteries (17.9%), congenital corrected transposition of the great arteries (13%). No intraprocedural complications were observed. Median follow up was 3.4 years (0.1-23). 24 patients (12%) developed EC (4 hematomas, 20 lead dislodgments). A total of 56 LC occurred (46% lead failure, 21% infection, 11% prophylactic lead extraction, 9% neurologic pain, 9% erosion, 4% other) with an incidence rate of LC of 18% per 5 person-years. Anatomic complexity (odds ratio 2.9,p=0.02) and CRTD implant(OR 2.5,p=0.04) were associated with EC. Survival free from LC was 92%, 86%, 65% respectively after 1,5 and 10 years. Presence of legacy leads (hazard ratio 2.9,p=0.006) and subpulmonary ejection fraction (5% increase, HR 1.35,p=0.031) were associated with LC. ACHD patients at risk of SCD continue to benefit from newer device technology. However, these patients-particularly those with greater anatomic and device complexity-remain at increased risk of developing complications over their lifetime. Given the life expectancy of this population, careful consideration needs to be given when a device for primary prevention is being contemplated.

Effect of Digitalis on ICD or CRT-D Recipients: A Systematic Review and Meta-Analysis

Digitalis has been widely utilized for heart failure therapy and several studies have demonstrated an association of digitalis and adverse outcome events in patients receiving implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds). Hence, we conducted this meta-analysis to assess the effect of digitalis on ICD or CRT-D recipients. We systematically retrieved relevant studies using the Cochrane Library, PubMed, and Embase database. A random effect model was used to pool the effect estimates (hazard ratios (HRs) and 95% confidence intervals (CIs)) when the studies were of high heterogeneity, otherwise a fixed effect model was used. Twenty-one articles containing 44,761 ICD or CRT-D recipients were included. Digitalis was associated with an increased rate of appropriate shocks (HR = 1.65, 95% CI: 1.46-1.86, p < 0.001) and a shortened time to first appropriate shock (HR = 1.76, 95% CI: 1.17-2.65, p = 0.007) in ICD or CRT-D recipients. Furthermore, the all-cause mortality increased in ICD recipients with digitalis therapy (HR = 1.70, 95% CI: 1.34-2.16, p < 0.01), but the all-cause mortality was unchanged in CRT-D recipients (HR = 1.55, 95% CI: 0.92-2.60, p = 0.10) or patients who received ICD or CRT-D therapy (HR = 1.09, 95% CI: 0.80-1.48, p = 0.20). The sensitivity analyses confirmed the robustness of the results. ICD recipients with digitalis therapy may tend to have higher mortality rates, but digitalis may not be associated with the mortality rate of CRT-D recipients. Further studies are required to confirm the effects of digitalis on ICD or CRT-D recipients.

Device-detected atrial fibrillation in a large remote-monitored cohort: implications for anticoagulation and need for new pathways of service delivery

BackgroundRemote monitoring (RM) can facilitate early detection of subclinical and symptomatic atrial fibrillation (AF), providing an opportunity to evaluate the need for stroke prevention therapies. We aimed to characterize the burden of RM AF alerts and its impact on anticoagulation of patients with device-detected AF.MethodsConsecutive patients with a cardiac implantable electronic device, at least one AF episode, undergoing RM were included and assigned an estimated minimum CHA2DS2-VASc score based on age and device type. RM was provided via automated software system, providing rapid alert processing by device specialists and systematic, recurrent prompts for anticoagulation.ResultsFrom 7651 individual, 389,188 AF episodes were identified, 3120 (40.8%) permanent pacemakers, 2260 (29.5%) implantable loop recorders (ILRs), 987 (12.9%) implantable cardioverter defibrillators, 968 (12.7%) cardiac resynchronization therapy (CRT) defibrillators, and 316 (4.1%) CRT pacemakers. ILRs transmitted 48.8% of all AF episodes. At twelve-months, 3404 (44.5%) AF < 6 min, 1367 (17.9%) 6 min–6 h, 1206 (15.8%) 6–24 h, and 1674 (21.9%) ≥ 24 h. A minimum CHA2DS2-VASc score of 2 was assigned to 1704 (63.1%) of the patients with an AF episode of ≥ 6 h, 531 (31.2%) who were not anticoagulated at 12-months, and 1031 (61.6%) patients with an AF episode duration of ≥ 24 h, 290 (28.1%) were not anticoagulated.ConclusionsDespite being intensively managed via RM software system incorporating cues for anticoagulation, a substantial proportion of patients with increased stroke risk remained unanticoagulated after a device-detected AF episode of significant duration. These data highlight the need for improved clinical response pathways and an integrated care approach to RM.Trial registrationAustralian New Zealand Clinical Trial Registry: ACTRN12620001232921.Graphical

Device-evaluated autonomic nervous function for predicting ventricular arrhythmias and all-cause mortality in patients who underwent cardiac resynchronization therapy-defibrillator.

Introduction: Autonomic nervous system (ANS) function quantified by heart rate variability (HRV) was associated with long-term prognosis, but it was rarely used in the evaluation of patients with heart failure, especially those with cardiac resynchronization therapy-defibrillator (CRT-D) implantation. This study aimed to describe the changes in ANS function among patients who underwent CRT-D with remote home monitoring function, and explore predictive value of HRV for ventricular tachyarrhythmias (VTAs) and all-cause mortality. Method: Patients who underwent CRT-D implantation were included. Device-measured all-day HR, night-time HR, and HRV (measured by the standard deviation of the atrial-atrial sensed intervals) were used to quantify ANS function. Multivariate Cox proportional hazards models were fitted to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of VTAs or all-cause mortality in relation to ANS function at baseline and 6months post-implantation. The cutoff value was determined using restrictive cubic splines. Multivariable logistic regression was further established to determine factors influencing postoperative HRV. Results: A total of 170 patients treated with CRT-D were eligible for analysis. During a median follow-up period of 50.8months, 61 patients died and 69 patients experienced at least one spontaneous episode of VTAs. At 6months after CRT implantation, 114 patients showed improvement in HRV, increasing from 66.4 ± 19.4ms to 76.7 ± 21.2ms. The postoperative HRV was associated with both all-cause mortality (HRs: 0.983; 95% CI: 0.968 to 0.998, p = 0.012) and VTAs (HRs: 0.973; 95% CI: 0.954 to 0.993, p = 0.008), and the relative risk would significantly increase when the postoperative HRV lower than 75ms. After adjusting for basic ANS function and possible influencing factors, patients without diabetes (p = 0.018) and with higher daily physical activity (p = 0.041) could maintain higher postoperative HRV after CRT implantation. Conclusion: More than two-thirds of heart failure patients showed improvement in ANS function following CRT treatment. However, patients with diabetes and low daily physical activity levels have difficulty maintaining a higher postoperative HRV, which is associated with a worse clinical outcome.