Search

Introduction: Defibrillation testing (DT) is recommended during the subcutaneous defibrillator (S-ICD) placement. We sought to compare 10 J shock impedance in sinus rhythm (SR) with 65 J defibrillation impedance and evaluate device position on a postimplant chest X-ray (CXR) using an intermuscular (IM) technique., Methods: Consecutive S-ICD implantations between 12/2019 and 12/2020 at The Ohio State University were reviewed. All implantations were performed using a two-incision IM technique. Standard DT with 65 J shock and 10 J shock in SR were performed unless contraindicated. The PRAETORIAN score was calculated based on CXR., Results: A total of 37 patients (age: 47.2 ± 15.8 years old, male: n = 26 [70.3%], body mass index: 30.1 ± 6.7 kg/m 2 ) underwent IM S-ICD implantation, and of those, 27 (73%) underwent both 65 J shock and 10 J shock in SR. The coefficient of determination (R 2 ) between 10 J shock impedance and 65 J shock impedance was 0.84. The mean of an impedance difference was 1.6 ± 4.8 Ω (minimum - 11 and maximum 8). Postimplant CXR was available for 33 out of 37 patients (89.2%). The PRAETORIAN score was less than 90 in all patients and the mean score was 32.7 ± 8.8., Conclusion: We demonstrated that 10 J shock impedance in SR correlated well with 65 J defibrillation impedance during IM S-ICD implantation. An IM implantation technique provides excellent generator location on postimplant CXR. The IM technique combined with 10 J shock in SR may be sufficient to predict and ensure the defibrillation efficacy of the S-ICD., (© 2021 Wiley Periodicals LLC.)

Objectives: This study reports resource use and economic implications of rhythm monitoring with subcutaneous cardiac rhythm monitors (SCRMs)., Background: SCRMs generate a substantial amount of data that requires timely adjudication for appropriate clinical care. Resource use for SCRM monitoring is not known., Methods: The study included consecutive transmissions during 4 weeks from 1,811 SCRMs. Resource use was quantified by assessment of time commitment of device clinic personnel and electrophysiologists for data adjudication. Incidence and characteristics of false positive (FP) episodes were assessed. Impact of custom programming for arrhythmia detection on incidence of FP episodes and resource use was analyzed., Results: A total of 1,457 transmissions (alerts = 462; full downloads = 995) were received during study period. Average device clinic personnel time for adjudication of 1 transmission was 15 ± 6 min. This totaled to 364 h spent (2.3 full-time staff) over the 4-week period, which translated into a salary cost of $12,000 U.S. dollars (USD). Average time spent by an electrophysiologist for 1 transmission was 1.5 ± 1 min and totaled to 37 h for 4 weeks, which translated into an estimated cost of $9,600 USD. Of 1,457 total transmissions, 512 (35%) represented multiple transmissions from the same patients, which resulted in no additional reimbursement. Incidence of FP episodes in the entire cohort was 50% and was variable in alert (60%) and full download (49%) (p = 0.04) transmissions. When SCRMs with manufacturer suggested nominal programming and institutional custom programming were compared, there was a reduction in FP episodes (55% vs. 16%; p = 0.01), which translated to a 34% reduction in resource use for data adjudication., Conclusions: SCRM data adjudication requires significant resources. Custom programming for SCRMs may overcome the data deluge., Competing Interests: Funding support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the feasibility and safety of same-day discharge after S-ICD implantation by implementing a specific analgesia protocol and phone follow-up., Methods: Consecutive patients presenting for outpatient S-ICD implantation were enrolled between 1/1/2018 and 4/30/2019. An analgesia protocol included pre-operative acetaminophen and oxycodone, intraoperative local bupivacaine, and limited use of oxycodone-acetaminophen at discharge. The primary outcome was successful same-day discharge. Numerical Pain Rating Scale (NPRS) on postoperative day (POD) 1, 3, 14, and 30 and any unplanned health care visits during the 1-month follow-up period were assessed., Results: Out of 53 potentially eligible S-ICD patients, 49 patients (92.5%) were enrolled and successfully discharged on the same day. Mean age of these 49 patients was 47 ± 14 years. There were no acute procedural complications. Severe pain (NPRS ≥ 8) on POD 0, 1, and 3 was present in 14.3%, 14.3%, and 8.2% of patients, respectively. The total in-hospital stay was 534 ± 80 min. Four unplanned visits (8%) due to cardiac or device-related issues occurred during 1-month follow-up, including 2 patients with heart failure exacerbation, one patient with an incisional infection, and one patient with inappropriate shocks., Conclusions: With the appropriate institutional protocol including specific analgesics and phone follow-up, same-day discharge after outpatient S-ICD implantation is feasible and appears safe for most patients.. Device-related pain can be severe in the first 3 days post-implantation and can be successfully treated with limited supply of narcotic medications.

Background: The perioperative anesthesia care during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving., Objective: To assess the feasibility and safety of S-ICD implantation with monitored anesthesia care (MAC) versus general anesthesia (GA) in a tertiary care center., Methods: This is a single-center retrospective study of patients undergoing S-ICD implantation between October 2012 and May 2019. Patients were categorized into MAC and GA group based on the mode of anesthesia. Procedural success without escalation to GA was the primary endpoint of the study, whereas intraprocedural hemodynamics, need of pharmacological support for hypotension and bradycardia, length of the procedure, stay in the post-anesthesia care unit, and postoperative pain were assessed as secondary endpoints., Results: The study comprises 287 patients with MAC in 111 and GA in 176 patients. Compared to MAC, patients in GA group were younger and had a higher body mass index. All patients had successful S-ICD implantation. Only one patient (0.9%) in the MAC group was converted to GA. Despite a similar baseline heart rate (HR) and mean arterial blood pressure (MAP) in both groups, patients with GA had significantly lower HR and MAP during the procedure and more frequently required pharmacological hemodynamic support. Length of the procedure, stay in the postanesthesia care unit, and postoperative pain was similar in both groups., Conclusion: This retrospective experience suggests that implantation of S-ICD is feasible and safe with MAC. Use of GA is associated with more frequent administration of hemodynamic drugs during S-ICD implantation., (© 2019 Wiley Periodicals, Inc.)

Background: An internal risk stratification algorithm was developed to decrease the risk of major adverse cardiac events (MACEs) during lead extractions (LEs)., Objective: To report upon the impact of a risk stratification algorithm (RISE [RIsk Stratification prior to lead Extraction] protocol) on outcomes of LEs in a high-volume center., Methods: A retrospective review of a prospectively maintained LEs database was performed to identify features associated with MACEs. On the basis of the retrospective data, the RISE protocol differentiated LEs procedures into "High" and "Low" risk for occurrence of MACEs. High-risk LEs included dual-coil defibrillator lead (≥3 years), pacemaker and single-coil lead (≥5 years), and any StarFix coronary sinus lead. During the prospective evaluation of the RISE protocol, "High-risk" LEs were performed in an operating room (OR) or hybrid laboratory with the cardiac anesthesiologist, OR nursing team, perfusionist in the room, and a cardiac surgeon on the premises. "Low-risk" LEs were performed in the electrophysiology (EP) laboratory with anesthesia provided by EP nursing team. The preintervention (pre-RISE) and postintervention (post-RISE) group spanned 19 and 40 months and consisted of 449 (632 leads) and 751 patients (1055 leads), respectively. The primary outcome of MACEs in the two groups was compared., Results: Protocol compliance was 100%. The primary outcome of MACEs occurred in 15 patients (3.34%) before and 12 (1.6%) after implementation of the RISE protocol (P = .04)., Conclusion: RISE identified a low-risk group where minimal resources are needed and allowed for rapid intervention in the high-risk group that reduced the consequences of MACEs., (© 2019 Wiley Periodicals, Inc.)

Introduction: Subclinical atrial fibrillation (AF), in the form of cardiac implantable device-detected atrial high rate episodes (AHREs), has been associated with increased thromboembolism. An implantable cardioverter-defibrillator (ICD) lead with a floating atrial dipole may permit a single lead (DX) ICD system to detect AHREs. We sought to assess the utility of the DX ICD system for subclinical AF detection in patients, with a prospective multicenter, cohort-controlled trial., Methods and Results: One hundred fifty patients without prior history of AF (age 59 ± 13 years; 108 [72%] male) were enrolled into the DX cohort and implanted with a Biotronik DX ICD system at eight centers. Age-, sex-, and left ventricular ejection fraction-matched single- and dual-chamber ICD cohorts were derived from a Cornell database and from the IMPACT trial, respectively. The primary endpoint were AHRE detection at 12 months. During median 12 months follow-up, AHREs were detected in 19 (13%) patients in the DX, 8 (5.3%) in the single-chamber, and 19 (13%) in the dual-chamber cohorts. The rate of AHRE detection was significantly higher in the DX cohort compared to the single-chamber cohort (P = .026), but not significantly different compared to the dual-chamber cohort. There were no inappropriate ICD therapies in the DX cohort. At 12 months, only 3.0% of patients in the DX cohort had sensed atrial amplitudes less than 1.0 mV., Conclusion: Use of a DX ICD lead allows subclinical AF detection with a single lead DX system that is superior to that of a conventional single-chamber ICD system., (© 2019 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals, Inc.)

Background and Objective: Worldwide adoption of the subcutaneous implantable cardioverter-defibrillator (S-ICD) for preventing sudden cardiac death continues to increase, as longer-term evidence demonstrating the safety and efficacy of the S-ICD expands. As a relatively new technology, comprehensive anesthesia guidance for the management of patients undergoing S-ICD placement is lacking. This article presents advantages and disadvantages of different periprocedural sedation and anesthesia options for S-ICD implants including general anesthesia, monitored anesthesia care, regional anesthesia, and nonanesthesia personnel administered sedation and analgesia., Methods: Guidance, for approaches to anesthesia care during S-ICD implantation, is presented based upon literature review and consensus of a panel of high-volume S-ICD implanters, a regional anesthesiologist, and a cardiothoracic anesthesiologist with significant S-ICD experience. The panel developed suggested actions for perioperative sedation, anesthesia, surgical practices, and a decision algorithm for S-ICD implantation., Conclusions: While S-ICD implantation currently requires higher sedation than transvenous ICD systems, the panel consensus is that general anesthesia is not required or is obligatory for the majority of patients for the experienced S-ICD implanter. The focus of the implanting physician and the anesthesia services should be to maximize patient comfort and take into consideration patient-specific comorbidities, with a low threshold to consult the anesthesiology team., (© 2018 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals, Inc.)

Background: The perioperative anticoagulation management during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving., Objective: The purpose of this study was to assess whether it is safe to perform S-ICD implantation with uninterrupted warfarin., Methods: This is a single-center retrospective review of patients undergoing S-ICD implantation between October 1, 2012 and June 30, 2017. One hundred thirty-seven patients underwent successful S-ICD implantation during the study period. The most common indication for implantation was primary prevention of sudden cardiac death. In 24 (17.5%) patients, warfarin was continued without any interruption (warfarin group). In 113 (82.5%) patients, no warfarin was used in the perioperative period (nonwarfarin group). The incidence of clinically significant lateral pocket hematoma was compared in the 2 groups., Results: The mean international normalized ratio was 1.83 ± 0.47 in the warfarin group and 1.09 ± 0.18 in the nonwarfarin group. A total of 8 patients developed a hematoma at the lateral pocket. No patient developed a hematoma at the parasternal pockets. Six patients (25%) in the warfarin group and 2 (1.5%) in the nonwarfarin group developed a significant lateral pocket hematoma (P = .001). The mean length of stay was longer in the warfarin group (1.23 ± 0.46 days) than in the nonwarfarin group (1.02 ± 0.18 days) (P = .0008). An international normalized ratio of >1.8 predicted the risk of hematoma. The concomitant use of dual antiplatelet therapy did not increase the risk of hematoma. None of the patients with a hematoma developed infection or required hematoma evacuation., Conclusion: Uninterrupted warfarin in the perioperative period during S-ICD implantation is associated with an increased risk of significant lateral pocket hematoma that results in prolonged hospital stay., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: During early experience with subcutaneous implantable cardioverter-defibrillators (S-ICD), several patients had inappropriate shocks from T-wave oversensing (TWOS) during exercise. This prompted some operators to perform routine treadmill exercise tests after implantation of S-ICD to screen for TWOS. Meanwhile, improvements have been made in the detection algorithms by the manufacturer., Objective: To assess whether routine treadmill exercise post S-ICD implantation is warranted., Methods: Patients undergoing S-ICD implantation from October 2012 to December 2016 who were able to complete a treadmill exercise were included in the study. The amplitude of R and T waves as assessed by the device programmer at rest and peak exercise was calculated and incidence of TWOS recorded., Results: Eighty-seven patients with complete treadmill exercise test data were included in the final analysis. The majority of the patients received S-ICD for primary prevention. Nine percent of the included patients had hypertrophic obstructive cardiomyopathy. During treadmill exercise, there was significant increase in the heart rate from rest (77 ± 14 beats per minute) to peak exercise (133 ± 14 beats per minute; P < .0001). There was no significant difference between R-wave amplitude at rest (2 ± 0.77 mV) and peak exercise (1.88 ± 0.94 mV; P = .36). Similarly, there was no significant difference between T-wave amplitude at rest (0.27 ± 0.19 mV) and peak exercise (0.33 ± 0.23 mV; P = .06). The incidence of TWOS during exercise was zero., Conclusions: With current screening and detection algorithms for S-ICD, routine treadmill exercise does not result in additional discrimination of patients susceptible to TWOS., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Antitachycardia pacing (ATP) is an effective treatment for ventricular tachycardia (VT) and can reduce the frequency of shocks in patients with an implantable cardioverter defibrillator (ICD). The association between survival and ATP, as compared to a shock, has not been confirmed in a large patient population. This study aims to determine if patients with an ICD receiving ATP have lower mortality, as compared to those receiving shock., Methods: Sixty-nine thousand three hundred and sixty-eight patients underwent ICD implantation between October 2008 and May 2013 and were enrolled in the remote monitoring network Merlin.net™ (St. Jude Medical, St. Paul, MN, USA). Patients were categorized into three groups based on the type of ICD therapy received during follow-up: no therapy (N = 47,927), ATP (N = 8,049), and shock (N = 13,392) groups. Survival was determined by linking implant records to the Social Security Death Index., Results: The no therapy (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.56-0.64, P < 0.001) and ATP (HR 0.70, 95% CI 0.64-0.77, P < 0.001) groups were associated with a lower mortality risk than the shock group. These results were unaffected by age, gender, device type, atrial fibrillation (AF) burden, or ventricular rate. ATP was effective in 85% of episodes and ATP effectiveness was dependent on the ventricular rate., Conclusions: Mortality rates were higher in ICD patients who received only ATP compared to no therapy, but ICD patients who received a shock had higher mortality compared to both groups. Furthermore, the data suggest that age, gender, device type, AF burden, and rate of arrhythmia do not change the trend of higher mortality in patients receiving ICD shock compared to ATP alone., (© 2017 Wiley Periodicals, Inc.)

Background: To date, general anesthesia has been suggested as the preferred approach for implantation of a subcutaneous implantable cardioverter-defibrillator (S-ICD). The purpose of this study was to assess the use of monitored anesthesia care (MAC) for S-ICD implantation. The goals were to assess adequate sedation and analgesia (efficacy endpoints) and major perioperative airway or hemodynamic compromise (safety endpoints). The authors hypothesized that MAC may provide adequate sedation and analgesia and no major perioperative airway or hemodynamic compromise during S-ICD implantation and multiple defibrillation threshold (DFT) testing., Methods: Prospectively collected data of patients who underwent S-ICD implantation with MAC from 2015 to 2016 were analyzed retrospectively. The efficacy endpoints were the provision of an optimal depth of sedation and analgesia to facilitate S-ICD implantation without intra-procedure patient discomfort or awareness, and the absence of "severe" pain at the lead tunneling and the generator insertion sites post-procedure. The safety endpoints included: (1) periprocedural hypotension, as defined by a mean arterial pressure (MAP)<60 mmHg refractory to conventional pharmacotherapy, (2) heart rate (HR)<45 bpm requiring pharmacologic support, and (3) sedation-induced airway compromise requiring endotracheal intubation., Measurements: MAP and HR were recorded during S-ICD implantation and DFT testing. The maximum and minimum infusion rates of propofol, supplemental sedatives, and analgesics, and doses of vasopressor and/or inotropic agents administered intra-procedurally were recorded. Post-procedure pain scores also were noted., Results: Ten patients underwent S-ICD implantation with MAC (mean age, 56 years; 50% men; mean left ventricular ejection fraction was 39%). Implantation of the S-ICD system using MAC was successful in all patients without any major adverse events. The mean baseline MAP was 92.8 mmHg, and the mean end-procedure MAP was 88 mmHg (p = 0.26). When compared to baseline and end-procedure, the mean lowest intra-procedure MAP was significantly lower (67.4 mmHg; p = 0.0001). The mean baseline HR was 65.7 bpm, and the mean end-procedure HR was 70.1 bpm (p = 0.28). When compared to baseline and end-procedure, the mean lowest intra-procedure HR was significantly lower (55.8 bpm; p<0.001). MAC was not associated with airway compromise in any patient, and post-procedure pain was rated as no greater than "mild"., Conclusions: Among a heterogeneous patient population undergoing S-ICD implantation and DFT testing, the use of MAC is efficacious, feasible, and safe., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The recently approved subcutaneous implantable cardioverter/defibrillator (S-ICD) uses a single extrathoracic subcutaneous lead to treat life-threatening ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. This is different from conventional transvenous ICDs, which are typically implanted under sedation. Currently, there are no reports regarding the anesthetic management of patients undergoing S-ICD implantation., Study Objectives: This study describes the anesthetic management and outcomes in patients undergoing S-ICD implantation and defibrillation threshold (DFT) testing., Methods: The study population consists of 73 patients who underwent S-ICD implantation. General anesthesia (n = 69, 95%) or conscious/deep sedation (n = 4, 5%) was used for device implantation., Measurements: Systolic blood pressure (SBP) and heart rate were recorded periprocedurally for S-ICD implantation and DFTs. Major adverse events were SBP <90 mm Hg refractory to vasopressor agents, significant bradycardia (heart rate <45 beats per minute) requiring pharmacologic intervention and, "severe" pain at the lead tunneling site and the S-ICD generator insertion site based on patient perception., Interventions: Of the 73 patients, 39 had SBP <90 mm Hg (53%), and intermittent boluses of vasopressors and inotropes were administered with recovery of SBP. In 2 patients, SBP did not respond, and the patients required vasopressor infusion in the intensive care unit., Main Results: Although the S-ICD procedure involved extensive tunneling and a mean of 2.5 ± 1.7 DFTs per patient, refractory hypotension was a major adverse event in only 2 patients. The mean baseline SBP was 132.5 ± 22.0 mm Hg, and the mean minimum SBP during the procedure was 97.3 ± 9.2 mm Hg (P < .01). There was also a mean 13-beats per minute decrease in heart rate (P < .01), but no pharmacologic intervention was required. Eight patients developed "severe" pain at the lead tunneling and generator insertion sites and were adequately managed with intravenous morphine., Conclusions: Among a heterogeneous population, anesthesiologists can safely manage patients undergoing S-ICD implantation and repeated DFTs without wide swings in SBP and with minimal intermittent pharmacologic support., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: We conducted this pilot randomized clinical trial to determine the feasibility of a large clinical trial aimed at testing whether early use of catheter ablation of ventricular tachycardia (VT) is superior to antiarrhythmic medications at reducing mortality., Methods and Results: Patients were enrolled at 4 sites if they had ischemic heart disease, an implantable cardioverter defibrillator (ICD), and received ≥1 ICD shock or ≥3 antitachycardia pacing therapies for VT. Patients were randomized to 2 arms: (1) antiarrhythmic medication (n = 14) and (2) catheter ablation (n = 13); patients were followed at 3 and 6 months. Endpoints included recurrent VT, time to first ICD therapy for VT, and death. Of 243 screened patients, 27 were enrolled. Main reasons for screen failures were: (1) patient was already on an antiarrhythmic medication (88 [41%]), (2) VT due to a reversible cause (23 [11%]), and (3) incessant VT (20 [9%]). Fourteen patients had recurrent VT, 8 (62%) in the ablation arm and 6 (43%) in the antiarrhythmic medication arm. Median time to recurrent VT was 75 days (25th, 75th: 51, 89) in the ablation arm and 57 days (30, 145) in the antiarrhythmic arm. Four patients died, 2 in each arm., Conclusion: This clinical trial shows that most patients in clinical practice have already failed antiarrhythmic drug therapy before catheter ablation is considered, and the VT recurrence rates and death in these patients are high. For a large clinical trial to be feasible, factors limiting early consideration of catheter ablation need to be identified and addressed., (© 2014 Wiley Periodicals, Inc.)

Background: The temporal relationship between atrial tachyarrhythmias (atrial tachycardia [AT] and atrial fibrillation [AF]) and cerebrovascular events/systemic emboli (CVE/SE) is unknown., Objective: The purpose of this study was to evaluate this relationship using stored AT/AF diagnostic data from implanted devices in patients with and those without AF., Methods: The TRENDS study enrolled 2,486 patients with an indication for an implantable device, at least one stroke risk factor, and available device data. The current study includes the subgroup of 40 (1.6%) patients enrolled in TRENDS who experienced CVE/SE., Results: AT/AF was detected prior to CVE/SE in 20 (50%) of 40 patients. Other than average and maximum daily AT/AF burden and duration of device monitoring prior to CVE/SE, no statistically significant differences were found between patients with and those without AT/AF prior to CVE/SE. For the 20 patients with AT/AF detected prior to CVE/SE, 9 (45%) did not have any AT/AF in the 30 days prior to CVE/SE. Therefore, 29 (73%) of 40 patients with CVE/SE had zero AT/AF burden within 30 days prior to CVE/SE. Fourteen (70%) of the 20 patients with AT/AF detected prior to CVE/SE were not in AT/AF at diagnosis of CVE/SE. The last episode of AT/AF in these 14 patients was 168 ± 199 days (range 3-642 days) before CVE/SE., Conclusion: The majority of CVE/SE in this population did not occur proximal to recent AT/AF episodes. These data imply that the mechanisms of CVE/SE in patients with implantable devices may importantly involve mechanisms other than cardioembolism due to atrial tachyarrhythmias., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: The purpose of this review is to summarize the numerous recent studies assessing the strategies to manage the increased risk of sudden cardiac death (SCD) early after a myocardial infarction (MI)., Recent Findings: Early after a MI, the risk of SCD is high. Several trials have been completed in attempt to identify and treat patients at increased risk for SCD early post-MI. These trials have evaluated QT interval, cardiac autonomic modulation, signal-averaged ECG, microvolt T-wave alternans, electrophysiology testing and early measurement of the left-ventricular ejection fraction (LVEF). Although some of these parameters were associated with increased total mortality, no parameter provided adequate predictive accuracy of increased risk for SCD that could guide use of an implantable cardiac defibrillator (ICD)., Summary: Other than LVEF measured more than 40 days post-MI (consistent with current ICD guidelines), there is no noninvasive or invasive test that reliably predicts the risk for SCD or that can guide empiric ICD implantation soon after a MI. In the early post-MI period, therefore, the goal is to maximize medical therapy and revascularization. The LVEF should then be measured no sooner than 40 days post-MI and, if the LVEF is 35% or less, the patient should be considered for ICD implantation.

Introduction: Intracardiac delay optimization of biventricular and dual-chamber pacing devices currently relies on time-consuming echocardiographic measurements. A novel intracardiac electrogram (IEGM) method for atrioventricular (AV/PV) and interventricular (VV) delay optimization was developed, which can be performed during routine device follow-up., Methods and Results: In this prospective, nonrandomized, multi-center trial, patients previously implanted with St. Jude Medical cardiac resynchronization therapy defibrillator (CRT-D) devices or dual-chamber implantable cardioverter defibrillators (ICDs) underwent standard AV/PV and/or VV delay optimization guided by Doppler echocardiogram measurements of the maximum aortic velocity time integral (aortic VTI). Aortic VTI measurements applying the IEGM method recommended delays were then obtained in all patients. Fifty-eight patients (age: 68 +/- 11 years; 81% male; 74% ischemic) and 57 patients (age: 71 +/- 10 years; 74% male; 71% ischemic) were enrolled for AV/PV and VV delay evaluation, respectively. An independent core lab determined the maximum aortic VTIs. Data analysis of the AV, PV, and VV delays demonstrated the concordance correlation coefficient (CCC) between the standard method aortic VTI values and the IEGM method aortic VTI values was 97.5%, 96.1%, and 96.6%, respectively. All analyses demonstrated that the CCC > 90% (P < 0.05)., Conclusion: The automated programmer-based IEGM method provides a reliable and simpler alternative to standard techniques for the optimization of AV/PV and VV delay settings in patients with CRT-D devices and dual-chamber ICDs.

Introduction: The acceptance of atrial arrhythmia features in implantable cardioverter defibrillators (ICDs) will depend on their ability to appropriately discriminate atrial tachyarrhythmias/atrial fibrillation (AT/AF). This study tested the effectiveness of an atrial/ventricular ICD with advanced atrial detection and new algorithms designed to prevent atrial arrhythmias., Methods and Results: Ninety-five patients were implanted with a dual chamber ICD (Model 1900, Guidant Corporation, MN, USA) at 25 US centers. Ten patients received a coronary sinus (CS) lead allowing a defibrillation vector for AT/AF cardioversion. Follow-up was 12.2 months. The addition of new atrial features designed for detection, discrimination, and prevention of AT/AF had no adverse effect upon detection of induced ventricular fibrillation (VF) (mean detection time with new features ON was 2.22 seconds vs 2.19 seconds with features OFF). A total of 100% of the induced and spontaneous ventricular and atrial arrhythmias receiving shock therapy were reviewed as appropriate detection. Atrial shock conversion efficacy for spontaneous and induced AT/AF episodes was 83% and 96%, respectively (144 spontaneous, 162 induced episodes). A 3-month randomized crossover trial of atrial preventative pacing features did not result in adverse effects, but there was no clinical efficacy for prevention of AT/AF., Conclusion: Enhanced atrial detection and discrimination features combined with tiered atrial therapies did not adversely impact the ability of the ICD (Model 1900) to appropriately detect and treat ventricular tachyarrhythmias.

Background: Sustained atrial fibrillation (AF) is a common risk factor for stroke. While intermittent AF also appears to pose a substantial stroke risk, the quantitative relationship between the percentage of time spent in AF and stroke risk is poorly specified and "intermittent" AF is not the same as paroxysmal AF. Improved assessment of the impact of AF burden on stroke risk will allow more targeted and safer use of antithrombotic therapy., Methods and Results: The primary objective of this study is to determine if AT/AF (all device detected atrial tachyarrhythmias, including atrial flutter, atrial fibrillation, and atrial tachycardia) burden over a 30 day period is an independent predictor of the occurrence of ischemic stroke, transient ischemic attack (TIA) and/or systemic embolism in subjects not receiving anticoagulation therapy. TRENDS is a prospective, post-market, non-randomized, multicenter study designed to enroll 3100 subjects who have an independent Class I/II indication for cardiac rhythm device implantation and who have demographic features suggestive of an increased risk for thromboembolic complications related to AT/AF. All implanted devices will have the ability to collect long-term AT/AF burden trending data and will be equivalently programmed to ensure consistent data collection. All subjects will be followed with device interrogations every 3 months and clinic visits every 6 months for 1 year. Subjects with a documented history of AT/AF prior to enrollment and those who develop AT/AF during the 12-month follow-up will be followed until the last subject enrolled in the study has completed their 24-month follow-up., Conclusions: The results of the TRENDS study should help clarify the implications of data retrieved from an implantable device with regard to the risk for thromboembolic complications from atrial arrhythmias, even in the absence of symptoms.

Patients with ICDs are commonly advised to quit industrial jobs because of concerns that strong electromagnetic fields operating in the industrial environment might interfere with ICD functions. This study was done to assess interactions between industrial equipment and ICDs, and to devise a simple low risk screening protocol. We studied 18 patients carrying nine different ICD models who were met at their workplace by a clinical technician and were asked to walk through their workplace and perform typical duties while sensing status was monitored by listening to the ICD's beeper. All devices were interrogated at the completion of testing. At follow-up, patients were contacted by phone and were asked about employment status and history of ICD discharges or syncope. One hundred eighty-four contacts with 114 types of industrial equipment in 13 different industrial facilities (including 31 contacts with arc welding machines) were monitored. Interference with ICD's function occurred in only one contact (0.5%), when ICD therapy was temporarily suspended while a worker was attaching a huge electromagnet to a crane. At follow-up 46.0 +/- 6.0 months after testing, 7 patients (41%) are still holding the same job, 7 have retired because of reasons unrelated to their ICD, and 3 patients were transferred to a nonindustrial job. None of the patients had either an ICD shock or syncope during work. The use of a simple screening procedure can safely identify sources of electromagnetic interference that may affect ICD operation, and can predict long-term safety of working in an industrial workplace for ICD patients.

Introduction: The aim of this study is to describe implantation techniques and lead performance for biventricular pacing, dual-chamber implantable cardioverter defibrillators (ICDs)., Methods and Results: A dual-chamber ICD with biventricular pacing was implanted in 87 patients with congestive heart failure (ejection fraction: 0.21 +/- 0.09), prolonged QRS duration (161 +/- 22 msec), and an indication for ICD therapy. Left ventricular pacing was achieved with a thoracotomy approach (n = 21) or a nonthoracotomy approach (n = 66). With a thoracotomy, biventricular devices were implanted successfully in all patients. During follow-up (17 +/- 11 months), 9 patients died (43%), 2 underwent transplantation, and 2 required left ventricular lead revision. At last follow-up, biventricular sensing and capture threshold were 11 +/- 5 mV and 1.5 +/- 0.8 V, respectively. For nonthoracotomy procedures, two types of coronary sinus (CS) leads were implanted: an over-the-wire lead (n = 45) and a shaped lead (n = 21). The rate of successful implantation (overall: 89%) (over-the-wire 93% vs shaped 81%; P = 0.1) and durations for CS lead placement (66 +/- 50 vs 58 +/- 34 min, P = 0.6) and the procedure (133 +/- 58 vs 129 +/- 33 min, P = 0.8) were not different between the two CS leads. During follow-up (11 +/- 9 months), 9 patients died (14%), and the shaped CS lead dislodged in 3 patients (3 shaped vs 0 over-the-wire, P = 0.01). At last follow-up, biventricular sensing and capture threshold were 10 +/- 4 mV and 1.8 +/- 0.7 V, respectively, and there was no difference between over-the-wire and shaped leads. By multivariate analysis, mortality was associated with absence of spironolactone therapy but not procedural features., Conclusion: Nonthoracotomy CS lead implantation is feasible, with a success rate of about 90% and few adverse events. For the remaining 10%, a thoracotomy approach can be completed safely in these ill patients without increased risk for death.

The long-term efficacy and safety of implantable atrial defibrillator (IAD) therapy in patients with AF and cardiovascular disease is unclear. The aim of this study was to evaluate the efficacy and safety of IAD therapy in patients with and without coexisting cardiovascular disease. In 115 patients implanted with an IAD, 85 patients had cardiovascular disease: 41 (48%) patients had 1 cardiovascular abnormality, 29 (35%) patients had 2, 13 (15%) patients had 3, and 2 (2%) patients had 4 different cardiovascular abnormalities. The device was programmed into a rhythm monitoring mode for the first 3-month postimplant period. All defibrillation therapy was performed under physician supervision to monitor safety and efficacy. After this initial monitoring period, patients were allowed to activate their device away from the hospital or clinic. A total of 357 spontaneous AF episodes occurred in 83 (72%) patients during observed operation and the mean shock efficacy was 93.5+/-20.3% (lower 95% confidence interval [CI] 89.8%). As of the lastfollow-up, 58 (55%) patients had transition to receive nonphysician observed therapy. Forty-two (72%) patients had experienced 332 episodes of AF for which theyhad received device therapy away from the hospital/clinic (mean shock efficacy 90.5+/-39.7%). The presence of hypertension, valvular heart disease, and ischemic heart disease did not affect the shock efficacy of the IAD during physician observed and nonobserved therapy (P > 0.05). However, the presence of congestive heart failure was associated with a lower clinical efficacy during observed and nonobserved therapy (P < 0.05). Overall, 5,262 shocks have been delivered with the IAD without any episode of proarrhythmia. The observed proarrhythmic risk was 0%, with an estimated maximum proarrhythmic risk of 0.06% per shock (95% upper CI). A stand-alone IAD appears to be safe in the presence of cardiovascular disease. The lower clinical efficacy for AF associated with congestive heart failure might be related to a higher rate of early reinitiation of AF after defibrillation.

Background: A recent study has shown that the implantable atrial defibrillator can restore sinus rhythm in patients with recurrent atrial fibrillation when therapy was delivered under physician observation. The objective of this study was to evaluate the safety and efficacy of ambulatory use of the implantable atrial defibrillator., Methods and Results: An atrial defibrillator was implanted in 105 patients (75 men; mean age, 59+/-12 years) with recurrent, symptomatic, drug-refractory atrial fibrillation. After successful 3-month testing, patients could transition to ambulatory delivery of shock therapy. Patients completed questionnaires regarding shock therapy discomfort and therapy satisfaction using a 10-point visual-analog scale (1 represented "not at all," 10 represented "extremely") after each treated episode of atrial fibrillation. During a mean follow-up of 11.7 months, 48 of 105 patients satisfied criteria for transition and received therapy for 275 episodes of atrial fibrillation. Overall shock therapy efficacy was 90% with 1.6+/-1.2 shocks delivered per episode (median, 1). Patients rated shock discomfort as 5.2+/-2.4 for successful therapy and 4.2+/-2.2 for unsuccessful therapy (P:>0.05). The satisfaction score was higher for successful versus unsuccessful therapy (3.4+/-3. 3 versus 8.7+/-1.3, P:<0.05). There was no ventricular proarrhythmia observed throughout the course of this study., Conclusions: Ambulatory use of an implantable atrial defibrillator can safely and successfully convert most episodes of atrial fibrillation, often requiring only a single shock. Successful therapy is associated with high satisfaction and only moderate discomfort.

Introduction: A variety of factors, including the number of defibrillation electrodes and shocking capacitance, may influence the defibrillation efficacy of an implantable defibrillator system. Therefore, the purpose of this study was to compare the defibrillation energy requirement using a 125 uF two-electrode defibrillation system and a 90 uF three-electrode defibrillation system., Methods and Results: The defibrillation energy requirements measured with both systems were compared in 26 consecutive patients. The two-electrode system used a single transvenous lead with two defibrillation coils in conjunction with a biphasic waveform from a 125 uF capacitor. The three-electrode system used the same transvenous lead, utilized a pectoral implantable defibrillator generator shell as a third electrode, and delivered the identical biphasic waveform from a 90 uF capacitor. The two-electrode system was associated with a higher defibrillation energy requirement (10.8 +/- 5.5 J) than was the three-electrode system (8.9 +/- 6.7 J, p < 0.05), however, the leading edge voltage was not significantly different between systems (361 +/- 103 V vs. 397 +/- 123 V, P = 0.07). The two-electrode system also had a higher shocking resistance (49.0 +/- 9.0 ohms vs. 41.4 +/- 7.3 ohms, p < 0.001) and a lower peak current (7.7 +/- 2.6 A vs. 10.1 +/- 3.7 A, p < 0.001) than the three-electrode system., Conclusions: A three-electrode defibrillation system that utilizes a dual coil transvenous lead and a subcutaneous pectoral electrode with lower capacitance is associated with a lower defibrillation energy requirement than is a dual coil defibrillation system with higher capacitance. This finding suggests that the utilization of a pectoral generator as a defibrillation electrode in conjunction with smaller capacitors is a more effective defibrillation system and may allow for additional miniaturization of implantable defibrillators.

Introduction: In patients undergoing defibrillator implantation, an appropriate defibrillation safety margin has been considered to be either 10 J or an energy equal to the defibrillation energy requirement. However, a previous clinical report suggested that a larger safety margin may be required in patients with a low defibrillation energy requirement. Therefore, the purpose of this prospective study was to compare the defibrillation efficacy of the two safety margin techniques in patients with a low defibrillation energy requirement., Methods and Results: Sixty patients who underwent implantation of a defibrillator and who had a low defibrillation energy requirement (< or = 6 J) underwent six separate inductions of ventricular fibrillation, at least 5 minutes apart. For each of the first three inductions of ventricular fibrillation, the first two shocks were equal to either the defibrillation energy requirement plus 10 J (14.6+/-1.0 J), or to twice the defibrillation energy requirement (9.9+/-2.3 J). The alternate technique was used for the subsequent three inductions of ventricular fibrillation. For each induction of ventricular fibrillation, the first shock success rate was 99.5%+/-4.3% for shocks using the defibrillation energy requirement plus 10 J, compared to 95.0%+/-17.2% for shocks at twice the defibrillation energy requirement (P = 0.02). The charge time (P < 0.0001) and the total duration of ventricular fibrillation (P < 0.0001) were each approximately 1 second longer with the defibrillation energy requirement plus 10 J technique., Conclusion: This study is the first to compare prospectively the defibrillation efficacy of two defibrillation safety margins. In patients with a defibrillation energy requirement < or = 6 J, a higher rate of successful defibrillation is achieved with a safety margin of 10 J than with a safety margin equal to the defibrillation energy requirement.

Background: Implantable cardioverter-defibrillator (ICD) therapy is integral to current therapy for ventricular tachycardia. Patients with an ICD frequently require concomitant antiarrhythmic drug therapy. Despite this, some patients still receive frequent ICD therapies for ventricular tachycardia. Therefore, the purpose of this prospective study was to determine the utility of ablation of ventricular tachycardia in patients with an ICD who experience frequent ICD therapies., Methods and Results: Twenty-one consecutive patients with frequent ICD therapies despite antiarrhythmic drug therapy were the subjects of this study. The mean age was 69+/-6 years, and 17 were men. The mean ejection fraction was 0.22+/-0.08, and all patients had coronary artery disease. During the 36+/-51 days (range, 4 days to 7 months) preceding the ablation procedures, the patients received 34+/-55 ICD therapies for the clinical ventricular tachycardia, or a mean of 25+/-88 ICD therapies per month. The patients underwent radiofrequency ablation of the presumed clinical ventricular tachycardia by inducing the tachycardia and mapping according to endocardial activation, continuous electrical activity, pace mapping, concealed entrainment, or mid-diastolic potentials. Ablation of the clinical arrhythmia was successful in 76% of patients during 1.4+/-0.6 (range, 1 to 3) ablation procedures and required 12.5+/-9.2 applications of energy. During 11.8+/-10.0 months of follow-up, the frequency of ICD therapies per month decreased from 60+/-80 before successful ablation to 0.1+/-0.3 ICD therapies per month after ablation (P=.01). A quality-of-life assessment demonstrated a significant improvement after successful (P=.02) but not unsuccessful ablation (P=.9)., Conclusions: Radiofrequency ablation of ventricular tachycardia as adjuvant therapy in patients with coronary artery disease and an ICD has a reasonable success rate, significantly reduces ICD therapies, and appears to be associated with an improved quality of life.

Background: The probability of successful defibrillation has been determined in normal animals but not in patients undergoing defibrillator implantation. Therefore, the purpose of this prospective study was to determine the probability of successful defibrillation in humans on the basis of a step-down defibrillation energy requirement., Methods and Results: Fifty-three consecutive patients underwent five separate inductions of ventricular fibrillation after the defibrillation energy requirement was determined with the use of small decrements and a step-down protocol (20, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, and 0.8 J). The first shock energy for defibrillation was either 1.0, 1.3, 1.5, 1.7, or 2.0 times the defibrillation energy requirement, and the likelihoods of successful defibrillation were 70+/-27%, 84+/-12%, 86+/-25%, 80+/-29%, and 88+/-32%, respectively (P=.03). The frequencies of uniformly successful defibrillation (5 of 5 defibrillation attempts) were 30%, 27%, 60%, 64%, and 73%, respectively (P=.01). Seven patients in whom the defibrillation energy requirement was <4 J had an overall rate of successful defibrillation of 54+/-20% compared with 86+/-20% in the remaining 47 patients (P=.002). The likelihood of successful defibrillation at twice the defibrillation energy requirement was 98% in the 46 patients with a defibrillation energy requirement of >4 J and 67% in the 7 patients with a defibrillation energy requirement of <4 J (P=.17). An absolute safety margin of 7 J was associated with a 96% probability of successful defibrillation., Conclusions: The probability of successful defibrillation is 70% at the defibrillation energy requirement. The probability plateaus at 88%, at twice the defibrillation energy requirement. A 96% probability of successful defibrillation is achieved at an absolute safety margin of 7 J, and a 98% success rate is achieved at energies that are twice the defibrillation energy requirement if the defibrillation energy requirement is >4 J. If the defibrillation energy requirement is <4 J, larger multiples of the defibrillation energy requirement are needed to achieve a high probability of successful defibrillation.

The chronic defibrillation energy requirement (DER) is believed to remain clinically stable in patients with defibrillators. Six patients (two with an epicardial and four with a nonthoracotomy system) were identified with a rise in their chronic DER, which eliminated a 10-J safety margin, thus necessitating a defibrillator lead system revision. The mean increase in DER was 14.7 +/- 4 J and was discovered at a mean of 16.0 +/- 18 months (range 2-41) following implantation. Management included placement of a defibrillator with a biphasic waveform, placement of an additional defibrillation electrode, or both. At 2 months following revision of the defibrillation system, a 10-J DER safety margin was present in each patient. In some patients, there is a progressive increase in the chronic DER with elimination of a 10-J safety margin necessitating revision of the defibrillation system. Routine reevaluation of the chronic DER, therefore, is necessary to identify these patients.

The main finding of this prospective, controlled study is that amiodarone and desethylamiodarone plasma concentrations < 1 mg/L are associated with a 23% increase in the acute defibrillation energy requirement and with a 31% increase in the requirement for a subcutaneous patch or array. The defibrillation energy requirement does not correlate with the plasma concentrations of amiodarone, desethylamiodarone, amiodarone plus desethylamiodarone, or with the duration or daily dosage of amiodarone therapy.

Previous studies have reported a significant morbidity and mortality associated with coronary artery bypass graft (CABG) surgery in conjunction with the placement of an implantable cardioverter defibrillator (ICD) with an epicardial lead system. In the absence of a control group, how significantly the component of concomitant placement of the ICD system contributes to these untoward outcomes remains unknown. The purpose of this study was to assess the short- and long-term complications in patients undergoing CABG surgery in conjunction with the placement of an ICD with epicardial leads and to compare these complications with those of patients who had only CABG surgery (control group). The study group (group A) consisted of 56 patients who underwent CABG surgery and placement of an ICD pulse generator with epicardial leads. A control group (group B) consisted of 56 patients who underwent CABG surgery only during the same time period. The two groups were matched for age, sex distribution, left ventricular function, surgical approach, number of bypass grafts per patient, bypass pump time, and length of follow-up period. The early mortality for group A was 7.1% versus 1.8% for group B (p > 0.05). The incidence of early morbidity (congestive heart failure, infection, supraventricular and ventricular arrhythmias) for groups A and B was similar (26.8% vs 25.0%, p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary revascularization has been suggested as sole therapy for secondary prevention of sudden cardiac arrest associated with ischemia. The use of implantable defibrillators (ICD) in combination with coronary revascularization for this patient population is unclear. Among 412 consecutive patients receiving an ICD, 23 (6%) were identified as sudden cardiac arrest survivors who were noninducible with programmed stimulation and had unstable angina or ischemia on a functional study; they underwent successful coronary revascularization. During a follow-up of 34 +/- 18 months, 10 (43%) of the 23 patients received ICD shocks (8 +/- 8 per patient, range 1 to 22 shocks), and nine of the 10 patients had syncope/presyncope associated with at least one ICD discharge. Patients with ICD discharges were compared with those without ICD discharges, and no clinical characteristics were statistically different between the two groups. In conclusion, revascularization alone may be inadequate therapy for survivors of sudden cardiac arrest associated with ischemia who are noninducible with programmed stimulation, and clinical variables cannot predict which patients are likely to have recurrent malignant ventricular arrhythmias.

Recognition of tachyarrhythmia by an implantable cardioverter-defibrillator (ICD) requires an intact rate-sensing lead. We retrospectively examined 266 consecutive patients requiring an ICD to characterize the incidence, clinical presentation, diagnosis, and management of a defective rate-sensing lead. To identify clinical parameters that may contribute to lead complications, we also assessed the effects of age, gender, type of rate-sensing lead, manufacturer of the lead, and surgeon. Over a follow-up period of 30 +/- 22 months (mean +/- standard deviation), a defective lead was found in 9 (3.4%) patients, in 9 (1.7%) of 514 leads over a period of 2 to 39 (mean 17 +/- 15) months after implantation. Except for 1 patient, in whom a lead fracture was incidently found during ICD generator replacement, these patients had multiple inappropriate shocks of recent onset. Clinical parameters were not helpful in identifying patients at risk for lead complication. An abnormal beeping signal obtained while the patients performed various maneuvers was helpful in confirming a defect. All of the defective leads were epicardial. These cases were managed by placement of a transvenous endocardial lead.