Computerized electrocardiogram data transformation enables effective algorithmic differentiation of wide QRS complex tachycardias.

BACKGROUND: Accurate automated wide QRS complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) can be accomplished using calculations derived from computerized electrocardiogram (ECG) data of paired WCT and baseline ECGs. OBJECTIVE: Develop and trial novel WCT differentiation approaches for patients with and without a corresponding baseline ECG. METHODS: We developed and trialed WCT differentiation models comprised of novel and previously described parameters derived from WCT and baseline ECG data. In Part 1, a derivation cohort was used to evaluate five different classification models: logistic regression (LR), artificial neural network (ANN), Random Forests [RF], support vector machine (SVM), and ensemble learning (EL). In Part 2, a separate validation cohort was used to prospectively evaluate the performance of two LR models using parameters generated from the WCT ECG alone (Solo Model) and paired WCT and baseline ECGs (Paired Model). RESULTS: Of the 421 patients of the derivation cohort (Part 1), a favorable area under the receiver operating characteristic curve (AUC) by all modeling subtypes: LR (0.96), ANN (0.96), RF (0.96), SVM (0.96), and EL (0.97). Of the 235 patients of the validation cohort (Part 2), the Solo Model and Paired Model achieved a favorable AUC for 103 patients with (Solo Model 0.87; Paired Model 0.95) and 132 patients without (Solo Model 0.84; Paired Model 0.95) a corroborating electrophysiology procedure or intracardiac device recording. CONCLUSION: Accurate WCT differentiation may be accomplished using computerized data of (i) the WCT ECG alone and (ii) paired WCT and baseline ECGs.

A wearable cardioverter defibrillator with a low false alarm rate.

INTRODUCTION: A wearable cardioverter defibrillator (WCD) is indicated in appropriate patients to reduce the risk for sudden cardiac death. Challenges for patients wearing a WCD have been frequent false shock alarms primarily due to electrocardiogram noise and wear discomfort. The objective of this study was to test a contemporary WCD designed for reduced false shock alarms and improved comfort. METHODS: One hundred and thirty patients with left ventricular ejection fraction ≤40% and an active implantable cardioverter defibrillator (ICD) were fitted with the ASSURE WCD (Kestra Medical Technologies) and followed for 30 days. WCD detection was enabled and shock alarm markers recorded, but shocks and shock alarms were disabled. All WCD episodes and ICD ventricular tachycardia/ventricular fibrillation (VT/VF) episodes were adjudicated. The primary endpoint was the false-positive shock alarm rate with a performance goal of 1 every 3.4 days (0.29 per patient-day). RESULTS: Of 163 WCD episodes, 4 were VT/VF and 159 non-VT/VF (121 rhythms with noise, 32 uncertain with noise, 6 atrial flutter without noise). Only three false-positive shock alarm markers were recorded; one false-positive shock alarm every 1333 patient-days (0.00075 per patient-day, 95% confidence interval: 0.00015-0.00361; p < .001). No ICD recorded VT/VF episodes meeting WCD detection criteria (≥170 bpm for ≥20 s) were missed by the WCD during 3501 patient-days of use. Median wear was 31.0 days (interquartile range [IQR] 2.0) and median daily use 23.0 h (IQR 1.7). Adverse events were mostly mild: skin irritation (19.4%) and musculoskeletal discomfort (8.5%). CONCLUSION: The ASSURE WCD demonstrated a low false-positive shock alarm rate, low patient-reported discomfort, and no serious adverse events.

The Saga of Defibrillation Testing: When Less Is More.

PURPOSE OF REVIEW: In the current era of implantable cardioverter-defibrillator procedures, the decision of whether or not to perform defibrillation threshold testing at the time of implantation is now less of a clinical conundrum. In this paper, we summarize this current practice, beginning with the physiology of defibrillation, followed by a review of the salient data, and discussion of specific situations where defibrillation threshold testing remains a clinical consideration. RECENT FINDINGS: Two prospective randomized trials demonstrated no mortality difference and no overall complication rate difference between patients who underwent defibrillation testing at implant compared with patients who underwent no defibrillation testing. Current recommendations support eliminating routine defibrillation testing in left-sided transvenous implantable cardioverter-defibrillator primary prevention implants. Defibrillation testing remains indicated in subcutaneous defibrillator implants in the absence of contraindications.

Regular tachycardia despite Wenckebach atrioventricular conduction.

We present a 21-year-old woman status post orthotopic heart transplantation initially presenting with a regular narrow complex tachycardia at 159beats/min. With intravenous diltiazem the rhythm transitioned to a regular tachycardia at 106beats/min, 2/3rd of the initial heart rate. We demonstrate this to be a novel description of 3:2second-degree Mobitz type I atrioventricular block (Wenckebach) with the absence of the hallmark regularly irregular (grouped beating) pattern.

Comparison of diagnostic value using a small, single channel, P-wave centric sternal ECG monitoring patch with a standard 3-lead Holter system over 24 hours.

BACKGROUND: To compare simultaneous recordings from an external patch system specifically designed to ensure better P-wave recordings and standard Holter monitor to determine diagnostic efficacy. Holter monitors are a mainstay of clinical practice, but are cumbersome to access and wear and P-wave signal quality is frequently inadequate. METHODS: This study compared the diagnostic efficacy of the P-wave centric electrocardiogram (ECG) patch (Carnation Ambulatory Monitor) to standard 3-channel (leads V1, II, and V5) Holter monitor (Northeast Monitoring, Maynard, MA). Patients were referred to a hospital Holter clinic for standard clinical indications. Each patient wore both devices simultaneously and served as their own control. Holter and Patch reports were read in a blinded fashion by experienced electrophysiologists unaware of the findings in the other corresponding ECG recording. All patients, technicians, and physicians completed a questionnaire on comfort and ease of use, and potential complications. RESULTS: In all 50 patients, the P-wave centric patch recording system identified rhythms in 23 patients (46%) that altered management, compared to 6 Holter patients (12%), P<.001. The patch ECG intervals PR, QRS and QT correlated well with the Holter ECG intervals having correlation coefficients of 0.93, 0.86, and 0.94, respectively. Finally, 48 patients (96%) preferred wearing the patch monitor. CONCLUSIONS: A single-channel ambulatory patch ECG monitor, designed specifically to ensure that the P-wave component of the ECG be visible, resulted in a significantly improved rhythm diagnosis and avoided inaccurate diagnoses made by the standard 3-channel Holter monitor.

Presentation and Prognosis of Excessive Asymptomatic Atrial Ectopy in Children and Adolescents With Structurally and Functionally Normal Hearts.

Excessive premature atrial complexes (PACs) in pediatric patients with a structurally normal heart are presumed to be benign and self-resolving, but no studies have confirmed this. Adults with excessive PACs, however, are at increased risk for future sustained atrial arrhythmias and cardiovascular morbidity and mortality. Therefore, we sought to evaluate the clinical course of frequent PACs in asymptomatic children. Patients < 21 years old with numerous asymptomatic PACs (>50/24 hours) were retrospectively selected over a 10-year period. Demographics, clinical characteristics, and results of cardiovascular testing were tabulated. Two groups were defined: those with a significant (>20%) reduction in burden of atrial ectopy versus those with an insignificant (<20%) reduction or increase. Of 6,902 patients, 343 patients (5%) met criteria. Initial median age was 8.3 (interquartile range [IQR] 4.1 to 14) years with comparable male:female ratio. Follow-up Holters were performed on 188 patients (54.8%) at a median interval of 2.2 (IQR 1.3 to 3.6) years. Overall, there was a significant decrease in atrial ectopy burden from 4.2% (IQR 1.9 to 6.5) down to 0.5% (IQR 0.01 to 2.3), with 166 patients (88.3%), demonstrating a decrease of over 20%. Five percent had a small increase, and 6% had an insignificant decrease. None developed cardiac symptoms or sustained supraventricular tachydysrhythmia. Male gender, athletic participation, and discontinuation of stimulant medications were the chief predictors for a reduction of PAC burden on follow-up. Atrial triplets at presentation were associated with a 5.4% increase. In conclusion, this study confirms that excessive asymptomatic childhood PACs with structurally normal hearts are rare and short-term to medium-term prognosis is benign.

Defibrillation effectiveness and safety of the shock waveform used in a contemporary wearable cardioverter defibrillator: Results from animal and human studies.

INTRODUCTION: The wearable cardioverter defibrillator (WCD) is used to protect patients at risk for sudden cardiac arrest. We examined defibrillation efficacy and safety of a biphasic truncated exponential waveform designed for use in a contemporary WCD in three animal studies and a human study. METHODS: Animal (swine) studies: #1: Efficacy comparison of a 170J BTE waveform (SHOCK A) to a 150J BTE waveform (SHOCK B) that approximates another commercially available waveform. Primary endpoint first shock success rate. #2: Efficacy comparison of the two waveforms at attenuated charge voltages in swine at three prespecified impedances. Primary endpoint first shock success rate. #3: Safety comparison of SHOCK A and SHOCK B in swine. Primary endpoint cardiac biomarker level changes baseline to 6 and 24 hours post-shock. Human Study: Efficacy comparison of SHOCK A to prespecified goal and safety evaluation. Primary endpoint cumulative first and second shock success rate. Safety endpoint adverse events. RESULTS: Animal Studies #1: 120 VF episodes in six swine. First shock success rates for SHOCK A and SHOCK B were 100%; SHOCK A non-inferior to SHOCK B (entire 95% CI of rate difference above -10% margin, p < .001). #2: 2,160 VF episodes in thirty-six swine. Attenuated SHOCK A was non-inferior to attenuated SHOCK B at each impedance (entire 95% CI of rate difference above -10% margin, p < .001). #3: Ten swine, five shocked five times each with SHOCK A, five shocked five times each with SHOCK B. No significant difference in troponin I (p = 0.658) or creatine phosphokinase (p = 0.855) changes from baseline between SHOCK A and SHOCK B. Human Study: Thirteen patients, 100% VF conversion rate. Mild skin irritation from adhesive defibrillation pads in three patients. CONCLUSIONS: The BTE waveform effectively and safely terminated induced VF in swine and a small sample in humans. TRIAL REGISTRATION: Human study clinical trial registration: URL: https://clinicaltrials.gov; Unique identifier: NCT04132466.

Cardiovascular implantable electronic device replacement infections and prevention: results from the REPLACE Registry.

BACKGROUND: Infection following cardiovascular implantable electronic device (CIED) replacement is a serious complication, and rates of infection have increased. Analysis of procedural and clinical data from device replacement procedures collected by the REPLACE Registry may provide insights into infection prevention strategies and outcomes. METHODS: We prospectively evaluated procedural complications in patients undergoing CIED replacement over 6 months from 72 U.S. sites. Major and minor infections were predefined and adjudicated by an independent blinded clinical events committee. Data regarding infection prevention strategies and infectious outcomes were analyzed for their potential relationships. RESULTS: A total of 1,744 patients were included in REPLACE. All patients received preoperative intravenous antibiotics and 68.7% received postoperative systemic antibiotic therapy. CIED infection developed in 22 patients (1.3%), of which 14 cases were major (0.8%, 95% confidence interval [CI] 0.4%-1.3%) and eight were minor (0.5%, 95% CI 0.2%-0.9%). Patients with infections were more likely to have had postoperative hematomas (five of 22 [22.7%] vs 17 of 1,722 [0.98%], P = 0.002). Participating sites experiencing infection rates >5% were more likely to use povidone-iodine for topical antisepsis, had lower implantation volume, and had patients with higher Charlson Comorbidity Index (2.79 vs 2.32, 95% CI for difference 0.08-0.86, P = 0.019). CONCLUSIONS: In this multicenter prospective study with 6 months of follow-up, infections associated with CIED replacements were surprisingly infrequent, possibly due to the use of preoperative antibiotics. Patients with infections were more likely to have had a postoperative hematoma, and sites with higher infection rates had sicker patients and lower overall procedural volume.

Concomitant Cox-Maze IV and Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy.

BACKGROUND: In patients with hypertrophic obstructive cardiomyopathy, atrial fibrillation is associated with heart failure and increased late mortality. However, the role of surgical ablation in these patients is not well defined. The aim of this study was to evaluate the efficacy of the concomitant Cox-Maze IV procedure in patients undergoing septal myectomy for hypertrophic obstructive cardiomyopathy. METHODS: Between 2005 and 2019, 347 patients who underwent septal myectomy at a single institution (Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, MO) were retrospectively reviewed. For patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent a concomitant Cox-Maze IV procedure, freedom from atrial tachyarrhythmias (ATAs) on or off antiarrhythmic drugs (AADs) was evaluated annually. Predictors of ATA recurrence were identified using Fine-Gray regression, with death as a competing risk. RESULTS: A total of 42 patients underwent concomitant septal myectomy and Cox-Maze IV procedures. The majority of patients, 69% (29 of 42), had paroxysmal atrial fibrillation with a 2.5-year median duration. Operative mortality was 7% (3 of 42). New York Heart Association functional class was reduced after surgery (P < .01). Rates of freedom from recurrent ATAs at 1- and 5-year intervals were 93% (27 of 29) and 100% (14 of 14), respectively. Rates of freedom from ATAs and AADs were 83% (24 of 29) and 100% (14 of 14) at the same time points, respectively. Increased left atrial diameter predicted first ATA recurrence (P < .01). Cerebrovascular accident risk was lower in patients with atrial fibrillation who underwent concomitant Cox-Maze IV and septal myectomy relative to myectomy only (P = .02). CONCLUSIONS: Late freedom from ATAs on or off AADs was excellent after Cox-Maze IV and septal myectomy. Although there was a higher than expected rate of perioperative complications, the study results suggest that concomitant surgical ablation should be considered in selected patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation.

Infection in patients with subcutaneous implantable cardioverter-defibrillator: Results of the S-ICD Post Approval Study.

BACKGROUND: Early subcutaneous implantable cardioverter-defibrillator (S-ICD) studies included atypical cohorts of patients who were younger with fewer comorbidities. Recent S-ICD studies included patient populations with more comorbidities. OBJECTIVES: The goals of this study were to determine the incidence and predictors of S-ICD-related infection over a 3-year follow-up period and to use these results to develop an infection risk score. METHODS: The S-ICD Post Approval Study is a US prospective registry of 1637 patients. Baseline demographic characteristics and outcomes with 3-year postimplantation follow-up were compared between patients with and without device-related infection. A risk score was derived from multivariable proportional hazards analysis of 22 variables. RESULTS: Infection was observed in 55 patients (3.3%), with 69% of infections occurring within 90 days and a vast majority (92.7%) within 1 year of implantation. Late infections more likely involved device erosion; no infections occurred after year 2. The annual mortality rate postinfection was 0.6%/y. No lead extraction complications or bacteremia related to infection were observed. An infection risk score was created with diabetes, age, prior transvenous ICD implant, and ejection fraction as predictors. Patients with a risk score of ≥3 had an 8.8 hazard ratio (95% confidence interval 2.8-16.3) of infection compared with a 0 risk score. CONCLUSION: Infection rates in the S-ICD Post Approval Study were similar to other S-ICD populations and not associated with systemic blood-borne infections. Late infection (>1 year) is uncommon and associated with system erosion. A high-risk infection cohort can be identified that may facilitate preventive measures.

Complication rates associated with pacemaker or implantable cardioverter-defibrillator generator replacements and upgrade procedures: results from the REPLACE registry.

BACKGROUND: Prospective studies defining the risk associated with pacemaker or implantable cardioverter-defibrillator replacement surgeries do not exist. These procedures are generally considered low risk despite results from recent retrospective series reporting higher rates. METHODS AND RESULTS: We prospectively assessed predefined procedure-related complication rates associated with elective pacemaker or implantable cardioverter-defibrillator generator replacements over 6 months of follow-up. Two groups were studied: those without (cohort 1) and those with (cohort 2) a planned transvenous lead addition for replacement or upgrade to a device capable of additional therapies. Complications were adjudicated by an independent events committee. Seventy-two US academic and private practice centers participated. Major complications occurred in 4.0% (95% confidence interval, 2.9 to 5.4) of 1031 cohort 1 patients and 15.3% (95% confidence interval, 12.7 to 18.1) of 713 cohort 2 patients. In both cohorts, major complications were higher with implantable cardioverter-defibrillator compared with pacemaker generator replacements. Complications were highest in patients who had an upgrade to or a revised cardiac resynchronization therapy device (18.7%; 95% confidence interval, 15.1 to 22.6). No periprocedural deaths occurred in either cohort, although 8 later procedure-related deaths occurred in cohort 2. The 6-month infection rates were 1.4% (95% confidence interval, 0.7 to 2.3) and 1.1% (95% confidence interval, 0.5 to 2.2) for cohorts 1 and 2, respectively. CONCLUSIONS: Pacemaker and implantable cardioverter-defibrillator generator replacements are associated with a notable complication risk, particularly those with lead additions. These data support careful decision making before device replacement, when managing device advisories, and when considering upgrades to more complex systems.

The cumulative effects and clinical safety of repeat magnetic resonance imaging on an MRI-conditional pacemaker system at 1.5 tesla.

BACKGROUND: Studies have demonstrated magnetic resonance imaging (MRI) safety in the presence of MRI-conditional permanent pacemakers (PPM). However, since patients' care may require serial MRIs, it is necessary to evaluate device safety and performance after multiple scans. OBJECTIVES: We evaluated safety and performance of MRI-conditional PPMs after serial MRIs over various anatomic regions performed during a multicenter, prospective, single-arm study (ProMRI). METHODS: ProMRI was a multiphase observational study designed to evaluate PPM performance after MRI scans. Our study evaluated PPM function in a cohort of patients who underwent multiple 1.5-T MRI scans. Selected patients underwent separate head, chest, and lumbar spine MRIs. Pacing capture threshold (PCT), lead impedance (LI), sensing amplitude, and battery capacity were collected before and after scanning. Freedom from serious adverse device effects (SADE) through 1 month post MRI served as a primary endpoint. Changes in PPM function parameters, including threshold success rate and sensing attenuation, were analyzed for statistical significance and clinical relevance. RESULTS: In 81 patients no adverse events or SADE occurred. Statistically significant changes in ventricular PCT (0.034 ± 0.15 V) immediately after, ventricular LI immediately after (-18.7 ± 44.2 Ω) and 1 month post phase B (-19.8 ± 44.9 Ω), and atrial sensing attenuation immediately after (-0.27 ± 0.92 mV) and 1 month post phase B (-0.22 ± 0.92 mV) were noted. However, these changes were not clinically relevant in degree. CONCLUSION: These results demonstrate the safety and performance of the ProMRI PPM in patients undergoing 3 serial MRIs over various anatomic regions.

AnaLysIs of Both sex and device specific factoRs on outcomes in pAtients with non-ischemic cardiomyopathy (BIO-LIBRA): Design and clinical protocol.

BACKGROUND: Outcomes of patients with nonischemic cardiomyopathy and low ejection fraction implanted with an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy with a defibrillator (CRT-D), especially in contemporary, real-life cohorts, are not fully understood. OBJECTIVE: We aimed to better characterize outcomes of death and ventricular tachyarrhythmias in patients with nonischemic cardiomyopathy, implanted with an ICD or CRT-D, and specifically assess differences by sex. METHODS: The AnaLysIs of Both Sex and Device Specific FactoRs on Outcomes in PAtients with Non-Ischemic Cardiomyopathy (BIO-LIBRA) study was designed to prospectively assess outcomes of device-treated ventricular tachyarrhythmias and all-cause mortality events in nonischemic cardiomyopathy patients, indicated for an ICD or CRT-D implantation for the primary prevention of sudden cardiac death (SCD), with a specific focus on sex differences. We will enroll a total of 1000 subjects across 50 U.S. sites and follow patients for up to 3 years. RESULTS: The primary objective of BIO-LIBRA is to evaluate the combined risk of all-cause mortality and treated ventricular tachycardia (VT) or ventricular fibrillation (VF) events by subject sex and by implanted device type. We will also assess all-cause mortality, VT or VF alone, cardiac death, and SCD in the total cohort, as well as by subject sex and by the implanted device type. In addition, the previously validated Seattle Proportional Risk Model (SPRM) will be used to compare the SPRM predicted incidence of SCD to the observed incidence. CONCLUSIONS: The BIO-LIBRA study will provide novel and contemporary information regarding outcomes in patients with a NICM who receive a defibrillator.

Left ventricular diastolic filling prior to cardiac resynchronization therapy: implications for atrioventricular delay programming.

BACKGROUND: The programmed atrioventricular delay (AVD) is an important determinant of the response in left ventricular (LV) systolic performance during cardiac resynchronization therapy (CRT). It is not well established if the optimal AVD for CRT may be influenced by the LV diastolic filling pattern. METHODS: Thirty patients were studied pre- and post-CRT at programmed AVD of 60-160 ms. Doppler measurements included the aortic and mitral velocity time integral (VTI), mitral early (E) and late diastolic filling (A) wave velocities, E- and A-wave VTI, and diastolic filling time (DFT). The optimal AVD for each of the Doppler variables was defined by the maximal improvement compared to pre-CRT. Patients were grouped by the pre-CRT mitral inflow pattern as impaired relaxation (IR, mitral E/A 1, n = 15). RESULTS: The percentage of improvement in aortic VTI was greater in the PNF/RF group (P = 0.03). Mitral E-wave velocity decreased in the PNF/RF group (P < 0 .001), E-wave VTI increased in both groups (P < 0 .05) and A-wave VTI increased in the PNF/RF group. DFT increased in both groups. The optimal AVD that maximized aortic VTI was longer than the AVD that improved DFT. CONCLUSIONS: The effects of various programmed AVD during CRT on the response in LV stroke volume and diastolic filling are influenced by the pre-CRT LV filling characteristics. AVD optimization based on maximizing DFT is shorter compared to the aortic VTI method.

The azygos defibrillator lead for elevated defibrillation thresholds: implant technique, lead stability, and patient series.

BACKGROUND: Conventional insertion of implantable cardioverter-defibrillator (ICD) includes an evaluation of the defibrillation threshold (DFT). Implanting an ancillary defibrillation lead in the azygos vein has been introduced as a therapeutic option in patients with "high" DFT. This study reports the efficacy and stability of azygos defibrillation coils implanted for elevated DFTs. METHODS: This is a retrospective review of seven consecutive patients with right and left pectoral, single- and dual-chamber, and biventricular ICDs and elevated DFTs, in whom an azygos defibrillation coil was introduced. RESULTS: Addition of an azygos defibrillator lead achieved a satisfactory safety margin during single energy defibrillation efficacy testing in four out of seven patients, with success at maximum device output in two patients. No satisfactory safety margin was achieved in the remaining patient, despite the further addition of a subcutaneous defibrillation coil. No change in lead position was observed over a mean radiographic follow-up of 8 months. No complications were noted during a mean follow-up of 14 months, including no deaths, and no ICD shocks. CONCLUSION: Implanting a defibrillation coil into the azygos vein is feasible and safe. In a majority of patients with failed defibrillation efficacy testing, adding an azygos coil achieves success on repeat testing. Therefore, this technique is one option for lowering the defibrillation threshold in patients who fail DFT testing of their ICD.

Relation of left ventricular lead placement in cardiac resynchronization therapy to left ventricular reverse remodeling and to diastolic dyssynchrony.

The effects of left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT) on LV remodeling and dyssynchrony are not well defined. Sixty-one patients (age 60 +/- 11 years, 76% men) were evaluated by echocardiography before and 4 +/- 2 months after CRT and grouped by the LV lead placement (lateral, posterolateral, or anterolateral). Echocardiographic measurements included LV volumes and LV ejection fraction. Tissue Doppler imaging was used to assess for inter- and intraventricular systolic and diastolic dyssynchrony. Analysis of variance was used to determine the effect of the LV lead placement on echocardiographic variables after CRT. The LV lead was placed in a lateral cardiac vein in 33 patients (54%), posterolateral in 15 (25%), and anterior in 13 (21%). Lateral LV lead placement was associated with significantly smaller LV volumes compared with the posterolateral lead placement (p <0.01). Diastolic dyssynchrony improved significantly with lateral lead placement compared with the anterior lead location (p <0.05). Improvement in LV ejection fraction and inter- and intraventricular systolic dyssynchrony was similar among the 3 groups. In conclusion, in patients undergoing CRT, a lateral lead location resulted in greater reverse LV remodeling and improved diastolic dyssynchrony compared with other lead placement locations.

Prevention of Cardiac Implantable Electronic Device Infections: Update and Evaluation of the Potential Role for Capsulectomy or the Antibiotic Pouch.

Cardiac implantable electronic device (CIED) infections can have devastating implications for patient morbidity and mortality. Over the past decade, the infection rate has risen out of proportion to implant rates, and has prompted the development of innovative solutions designed to reduce infections. The first section of this review provides a summary of the contemporary knowledge regarding the incidence, prevalence, microbiology, and risk factors for cardiac implantable electronic device infections. The second section addresses prevention with an emphasis on the potential role of novel procedural approaches, such as capsulectomy and the antibacterial envelope, in reducing CIED infection.

Complications Associated With Implantable Cardioverter Defibrillators in Adults With Congenital Heart Disease or Left Ventricular Noncompaction Cardiomyopathy (From the NCDR® Implantable Cardioverter-Defibrillator Registry).

Patients with childhood heart disease are living longer and entering adulthood, and may undergo implantable cardioverter-defibrillator (ICD) implantation to reduce the risk of sudden death. We evaluated the characteristics of adult patients with congenital heart disease or left ventricular noncompaction cardiomyopathy (LVNC) in the National Cardiovascular Disease Registry ICD Registry and determined ICD-related in-hospital complications. Patients with LVNC or transposition of the great arteries, tetralogy of Fallot, Ebstein's anomaly, atrial septal defect, ventricular septal defect, or common ventricle were identified in the registry. In-hospital complications were compared among different diagnoses using the chi-square test for categorical variables and the F-test in analyses of variance for continuous variables. A total of 3,077 patients were identified. The mean age was 48.0 ± 16.0 years, and 39.9% were female. Single-chamber ICDs were implanted in 25.2%, dual chamber in 41.9%, and cardiac resynchronization in 30.8%. Intraprocedural or postprocedural complications occurred in 70 patients (2.3%); there were 6 in-hospital deaths (0.2%). The most frequent complications were acute lead dislodgments, pneumothorax, and hematomas. Patients with Ebstein's anomaly had the greatest complication rate (8.3%, p = 0.03). The complication rate was 1.55% in single-chamber devices, 1.86% in dual chamber, and 3.5% in cardiac resynchronization (p < 0.001). For initial implants, the complication rate was 2.55%, 1.62% in generator replacements, and 8.77% in lead revisions (p = 0.001). In conclusion, in this large contemporary adult cohort of congenital heart disease and LVNC patients who underwent ICD implant procedures, periprocedural complication rates were low. Lead-related risks predominated.

Radiofrequency ablation of atrioventricular nodal reentrant tachycardia using a novel magnetic guidance system compared with a conventional approach.

BACKGROUND: A novel magnetic guidance system has been developed that allows the operator to remotely navigate an electrophysiology mapping/ablation catheter to precise locations in the heart for treatment of tachyarrhythmias. To date, this new technology has not been directly compared with the conventional approach. OBJECTIVE: To compare the use of the magnetic guidance system to the conventional approach for ablation of atrioventricular nodal reentry tachycardia. METHODS: Between November 2002 and October 2004, 28 patients with atrioventricular nodal reentry tachycardia treated with the magnetic guidance system were retrospectively compared with 28 matched control patients. RESULTS: Patients treated using the magnetic guidance system had similar procedure durations and fluoroscopy times compared with the matched controls. The only statistically significant difference between the groups was a longer time between insertion of the ablation catheter and placement of the first radiofrequency lesion in the magnetic guidance system cohort (23.3 +/- 12.0 vs. 10.5 +/- 13.9, p=0.001), possibly due to the research protocol. However, there was a trend toward a shorter total time that radiofrequency energy was applied in the magnetic guidance system cohort (5.2 +/- 4.5 vs. 8.0 +/- 7.2, p=0.087). There were no major complications or recurrences after at least 3 months of follow-up among the patients treated with the magnetic guidance system. CONCLUSION: The magnetic guidance system appears to have similar, and possibly improved, clinical efficacy compared with conventional catheter navigation for the treatment of atrioventricular nodal reentrant tachycardia.