Cardiac Magnetic Resonance and Cardiac Implantable Electronic Devices: Are They Truly Still "Enemies"?

The application of cardiac magnetic resonance (CMR) imaging in clinical practice has grown due to technological advancements and expanded clinical indications, highlighting its superior capabilities when compared to echocardiography for the assessment of myocardial tissue. Similarly, the utilization of implantable cardiac electronic devices (CIEDs) has significantly increased in cardiac arrhythmia management, and the requirements of CMR examinations in patients with CIEDs has become more common. However, this type of exam often presents challenges due to safety concerns and image artifacts. Until a few years ago, the presence of CIED was considered an absolute contraindication to CMR. To address these challenges, various technical improvements in CIED technology, like the reduction of the ferromagnetic components, and in CMR examinations, such as the introduction of new sequences, have been developed. Moreover, a rigorous protocol involving multidisciplinary collaboration is recommended for safe CMR examinations in patients with CIEDs, emphasizing risk assessment, careful monitoring during CMR, and post-scan device evaluation. Alternative methods to CMR, such as computed tomography coronary angiography with tissue characterization techniques like dual-energy and photon-counting, offer alternative potential solutions, although their diagnostic accuracy and availability do limit their use. Despite technological advancements, close collaboration and specialized staff training remain crucial for obtaining safe diagnostic CMR images in patients with CIEDs, thus justifying the presence of specialized centers that are equipped to handle these type of exams.

Impact of a pharmacist-managed remote heart failure program in patients with a multisensor-capable implanted device

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Added layers of remote management in heart failure (HF) have become available for patients with an implantable cardioverter defibrillator (ICD). The aim of this study was to investigate the impact of pharmacist-managed HF monitoring in patients with a multisensor-capable ICD.

METHODS

This was a retrospective, data-only, single-arm study that compared primary outcome events individually in the preactivation and postactivation periods at a single center. 23The primary outcomes were the total number of all-cause and HF-related hospitalizations and all-cause emergency department (ED) visits and the median length of stay for all-cause and HF-related hospitalizations. The secondary outcome quantified medication utilization.

RESULTS

In total, 132 patients completed the 1-year follow-up period. Overall, there was a 49% reduction in the number of patients with an all-cause hospitalization, a 77% reduction in the number of patients with an HF-related hospitalization, and a 36% reduction in the number of patients with an ED visit. More patients were hospitalized, visited the ED (P < 0.005), and had a longer median length of stay for all-cause hospitalizations in the preactivation period (P < 0.05). Overall medication utilization increased in the postactivation period.

CONCLUSION

A pharmacist-led remote monitoring program, utilizing a multisensor diagnostic, was effective at significantly reducing hospitalizations, ED visits, and length of stay.

Heart Failure and Cardiac Device Therapy: A Review of Current National Institute of Health and Care Excellence and European Society of Cardiology Guidelines

Guidelines help clinicians to deliver high-quality care with therapies based on up-to-date evidence. There has been significant progress in the management of heart failure with regards to both medication and cardiac device therapy. These advances have been incorporated into national and international guidelines with varying degrees of success. This article reviews current guidance from the National Institute of Health and Care Excellence in the UK and compares this with European Society of Cardiology guidelines, and evaluates how differences between them may impact on clinical practice.

Iatrogenic Hypoxemia and Atrial Septal Defect Due to Electrical Storm Ablation After Left Ventricular Assist Device: A Case Report

A 59-year-old male with an implantable cardiac defibrillator, left ventricular assist device, and refractory ventricular tachycardia presented with hypoxemia due to a post-ablation iatrogenic atrial septal defect. Left ventricular assist devices generate pressure gradients that may exacerbate intracardiac shunts and can precipitate significant hypoxemia.

Admission triglyceride-glucose index is predictor of long-term mortality and appropriate implantable cardiac defibrillator therapy in patients with heart failure

Background: In this study, the main aim was to evaluate the relation of the triglyceride-glucose (TyG) index to long-term mortality and proper shock therapy in patients with an implantable cardiac defibrillator (ICD) implanted for heart failure with reduced ejection fraction. Methods: This retrospective study group consisted of 773 patients treated with ICD for heart failure with reduced ejection fraction. The long-term prognostic effect of the TyG index among tertiles was evaluated regarding mortality and appropriate ICD therapy. Results: In the adjusted model, the mortality rates were 14.0% (hazard ratio: 2.24; 95% CI: 1.42-6.88) in tertile 2 and 23.3% (hazard ratio: 3.88; 95% CI: 1.84-14.38) in tertile 3. Conclusion: The TyG index was found to be an independent predictive marker for both long-term mortality and appropriate ICD therapy.

Radial and Circumferential CMR-Based RV Strain Predicts Low R Wave Amplitude after ICD Implantation in Patients with Arrhythmogenic Cardiomyopathy

Inadequate R wave amplitude (RWA) after implantable cardiac defibrillator (ICD) implantation in patients with arrhythmogenic cardiomyopathy (ACM) was suspected to relate to right ventricle impairment. However, little data-based evidence was provided to quantify the association. We retrospectively enrolled ACM patients receiving CMR examinations before transvenous ICD implantation from Fuwai Hospital. The RWA was obtained within 24 h and at 2-6-month follow-up after the operation. Structural, functional, as well as tissue characterization of the left ventricle (LV) and right ventricle (RV), were analyzed in relation to RWA. Among the 87 ACM patients (median RWA: 8.0 mV), 19 (21.8%) patients were found with low initial RWA (<5 mV) despite attempts in multiple positions. RV end diastolic diameter (RVEDD), (r = -0.44), RV ejection fraction (RVEF, r = 0.43), RV end diastolic volume index (RVEDVi, r = -0.49), RV end systolic volume index (RVESVi, r = -0.53), RV global circumferential (RVGCS, r = -0.64), and radial strain (RVGRS, r = 0.61, all p < 0.001) rather than LV metrics correlated strongly with initial RWA. RVGCS, RVESVi, and RVGRS were decent predictors of low RWA (areas under the curve AUC: 0.814, 0.769, 0.757, respectively) early after implantation and during 2-6-month follow-up. To summarize, low RWA of ICD lead in ACM patients was associated with RV abnormalities. The RVGCS, RVGRS, and RVESVi can be valuable predictors for identifying low RWA prior to ICD implantation.

Effect of Home-Based Cardiac Rehabilitation Program on Self-Efficacy of Patients With Implantable Cardioverter Defibrillator

Introduction

For more effective control and treatment of cardiac dysrhythmias caused by diseases, ischemia, or other causes, an implantable cardioverter defibrillator (ICD) is used. One of the effective ways for secondary prevention is the home-based cardiac rehabilitation (HBCR) which nurses have an effective role in its implementation.

Objective

The study aimed to investigate the effect of implementing HBCR programs on the self-efficacy of patients with ICD.

Methods

This is a semi-experimental study conducted on 70 patients who received ICD in Shahid Chamran Heart Center of Isfahan University of Medical Sciences (IUMS) in 2021. The patients were randomly assigned to intervention and control groups and were introduced to the practical concepts of HBCR during four training sessions. In the following, 3-month follow-up and trainings were continued by home visits, telephone follow-up, and use of social messaging networks due to the conditions of coronavirus disease 2019 (COVID-19) pandemic. The data were analyzed with SPSS/21.

Results

The findings showed that performing HBCR programs was effective in improving the self-efficacy of patients with ICDs. A significant trend in the implementation of the HBCR programs in two groups was shown using chi-square test and independent t-test and variance with repeated measurements (p < .001). There was no significant difference in self-efficacy score in both groups at the beginning of the study (p < .056).

Conclusion

Considering the effectiveness of HBCR programs on improving the self-efficacy of patients with ICDs, it can be used in the educational care programs of healthcare workers and in the strategic policies of health care services.

The mortality for the implantable cardiac defibrillator in nonischemic cardiomyopathy: An updated systematic review and meta-analysis

The implantable cardiac defibrillator (ICD) is common for the management of nonischemic cardiomyopathy (NICM). Mortality is a crucial issue for patients with NICM. We can understand the mortality events of ICD versus medicine treatment via a systemic review and meta-analysis of randomized clinical trials. The comparison between ICD treatment and medicine treatment was performed to find if the ICD treatment can be associated with lower relative risk and hazard ratio of mortality than the medicine treatment. In addition, the different kinds of mortality events were analyzed for the ICD treatment. After a restricted selection, 9 studies with a total of 4001 NICM patients were enrolled. The focused outcome was the events of all-cause mortality, sudden cardiac death, and cardiovascular death. The results showed that ICD treatment might be associated with lower relative risk and hazard ratio of all-cause mortality and sudden cardiac death. However, the relative risk and hazard ratio of cardiovascular mortality was not significantly different between ICD treatment and medicine treatment. In the current meta-analysis, the ICD treatment might show a lower relative risk and hazard ratio of all-cause mortality and sudden cardiac death when compared with medicine treatment. However, no significant differences were observed in cardiovascular mortality between ICD and medicine treatment.

Is it feasible to outsource the remote monitoring of implantable cardiac defibrillators in a large tertiary hospital?

AIM

To provide a detailed description of the workflow at our telecardiology centre and to analyse the workload of real-world remote monitoring with the aim to assess the feasibility to outsource this service.

METHODS

A retrospective analysis was conducted on the telecardiology service provided at the University Hospitals of Leuven by extracting patient demographic data, general time usage and detailed information about the type of remote contacts. 10,869 contacts in 948 patients have been included. A 2-week prospective study was conducted on the same service by documenting and monitoring every action performed by specialised nurses when analysing and solving remote monitoring transmissions. 337 contacts in 262 patients were collected during this period.

RESULTS

Both analyses indicated similar numbers of events and interventions. Unplanned transmissions were more challenging and required more interventions than planned transmissions. Relatively little time (retrospective median: 1.83 min; prospective median: 1.56 min, per event) was spent on incoming non-actionable 'normal' transmissions (retrospective: 46%; prospective: 40% of all events). Retrospectively 54% and prospectively 60% of transmissions showed abnormalities and were responsible for most of the time expended. Disease-related issues were the most frequent cause for these 'abnormal' alerts. Contacting patients and physicians were key interventions undertaken. Interaction initiated by patients mainly involved the installation process (42%) and bedside monitoring problems (32%).

CONCLUSION

External data centres could deal with 40% of the transmissions, but the decline in workload would be negligible for the in-hospital remote monitoring team, because very little time is spent dealing with the many 'non-event' transmissions whereas most of the time is spent solving clinical problems. Providing sufficient resources and optimising communication protocols is necessary to aid in managing the workload of the remote monitoring team.

Implications for practiceContacting patients and physicians are key interventions for specialist nurses in remote monitoring centres.Detailed timing confirmed that most time was spent on relevant disease-related clinical problems.Despite dealing with ∼40% of transmissions, outsourcing to external data centres would decrease the workload only by 15-25%.Patient initiated contacts with questions concerning remote monitoring form a high burden and should be countered by scaling the service and creating communication protocols.

Step by Step through the Years-High vs. Low Energy Lead Extraction Using Advanced Extraction Techniques

Background: Limited data is available about the outcome of TLE in patients with vs. without high energy leads in the last decade. Methods: This is an analysis of consecutive patients undergoing TLE at a high-volume TLE centre from 2001 to 2021 using the stepwise approach. Baseline characteristics, procedural details and outcome of patients with high energy lead (ICD group) vs. without high energy lead (non-ICD group) were compared. Results: Out of 667 extractions, 991 leads were extracted in 405 procedures (60.7%) in the ICD group and 439 leads in 262 procedures (39.3%) in the non-ICD group. ICD patients were significantly younger (median 67 vs. 74 years) and were significantly less often female (18.1% vs. 27.7%, p < 0.005 for both). Advanced extraction tools were used significantly more often in the ICD group (73.2% vs. 37.5%, p < 0.001), but there were no significant differences in the successful removal (98.8% vs. 99.2%) or complications (4.7% vs. 3.1%) between the groups (p > 0.2 for both). Discussion: Using the stepwise approach, overall procedural success was high and complication rate was low in a high-volume centre. In patients with a high energy lead, the TLE procedure was more complex, but outcome was similar to comparator patients.

Predictors of appropriate implantable cardiac defibrillator therapy in cardiac sarcoidosis

BACKGROUND

Cardiac sarcoidosis (CS) is associated with an increased risk for sudden cardiac death. An implantable cardiac defibrillator (ICD) is recommended in a subgroup of CS patients. However, the recommendations for primary prevention differ between guidelines. The purpose of the study was to evaluate the efficacy and safety of ICDs in CS and to identify predictors of appropriate therapy.

METHODS

A retrospective cohort study was performed in CS patients with an ICD implantation between 2010 and 2019. Primary outcome was appropriate ICD therapy. Independent predictors were calculated using Cox proportional hazard analysis.

RESULTS

105 patients were included. An ICD was implanted for primary prevention in 79%. During a median follow-up of 2.8 years, 34 patients (32.4%) received appropriate ICD therapy of whom 24 (22.9%) received an appropriate shock. Three patients (2.9%) received an inappropriate shock due to atrial fibrillation. Independent predictors of appropriate therapy included prior ventricular arrhythmias (hazard ratio [HR]: 10.5 [95% confidence interval (CI): 5.0-21.9]) and right ventricular late gadolinium enhancement (LGE) (HR: 3.6 [95% CI: 1.7-7.6]). Within the primary prevention group, right ventricular LGE (HR: 5.7 [95% CI: 1.6-20.7]) was the only independent predictor of appropriate therapy. Left ventricular ejection fraction did not differ between patients with and without appropriate therapy (44.4% vs. 45.6%, p = .70).

CONCLUSION

In CS patients with an ICD, a high rate of appropriate therapy was observed and a low rate of inappropriate shocks. Prior ventricular arrhythmias and right ventricular LGE were independent predictors of appropriate therapy.

How to Perform Extrathoracic Venous Access for Cardiac Implantable Electronic Devices Placement: Detailed Description of Techniques

Venous access is needed for the implantation of cardiac implantable electronic devices (CIED) with endocardial leads. Extrathoracic venous access in the prepectoral region has become the standard of care for CIED implantation because of lower risks for pneumothorax and likely less lead malfunction due to the subclavian crush syndrome. The most common extrathoracic venous access sites in the pectoral region are extrathoracic subclavian vein access, axillary vein access, and cephalic vein access. This review provides a detailed description of the anatomy, technical considerations, and the relative advantages and disadvantages for each of these extrathoracic venous access sites.

Real-world evaluation of followup strategies after ICD therapies in patients with VT (REFINE-VT)

Implantable cardiac defibrillators (ICDs) can prevent sudden cardiac death, but the risk of recurrent ventricular arrhythmia (VA) and ICD shocks persist. Strategies to minimise such risks include medication optimisation, device programming and ventricular tachycardia (VT) ablation. Whether the choice of these interventions at follow-up are influenced by factors such as the type of arrhythmia or ICD therapy remains unclear. To investigate this, we evaluated ICD follow-up strategies in a real-world population with primary and secondary prevention ICDs. REFINE-VT (Real-world Evaluation of Follow-up strategies after Implantable cardiac-defibrillator therapies in patients with Ventricular Tachycardia) is an observational study of 514 ICD recipients recruited between 2018 and 2019. We found that 77 patients (15%) suffered significant VA and/or ICD therapies, of whom 26% experienced a second event; 31% received no intervention. We observed an inconsistent approach to the choice of strategies across different types of arrhythmias and ICD therapies. Odds of intervening were significantly higher if ICD shock was detected compared with anti-tachycardia pacing (odds ratio [OR] 8.4, 95% confidence interval [CI] 1.7 to 39.6, p=0.007). Even in patients with two events, the rate of escalation of antiarrhythmics or referral for VT ablation were as low as patients with single events. This is the first contemporary study evaluating how strategies that reduce the risk of recurrent ICD events are executed in a real-world population. Significant inconsistencies in the choice of interventions exist, supporting the need for a multi-disciplinary approach to provide evidence-based care to this population.

Successful termination of ventricular arrhythmias with implantable cardioverter defibrillator in a patient with myotonic dystrophy

Összefoglaló. A dystrophia myotonica (DM) multiszisztémás, autoszomális domináns módon öröklődő, többségében felnőttkori izombetegség, melynek incidenciája 1 : 8000. A betegség kapcsán fellépő izomszöveti degeneráció a harántcsíkolt izomszövet átépülése mellett a szívizomszövetet is érinti, ami fontos oki szerepet játszik az érintett betegek csökkent várható élettartamában. A DM-ben szenvedők halálozásának közel egyharmadáért a cardiovascularis okok tehetők felelőssé. Esetriportunkban egy 52 éves, korábban kritikus bradycardia és I. fokú atrioventricularis blokk miatt pacemakerimplantáción átesett, DM-mel diagnosztizált nőbeteg kardiológiai utánkövetését mutatjuk be. A hirtelen szívhalál rizikóstratifikációja céljából elvégzett invazív elektrofiziológiai vizsgálat során kamrafibrilláció lépett fel, így a korábban implantált pacemakerelektródák mellé sokkelektróda került beültetésre, a pacemakerkészüléket implantálható kardioverter-defibrillátorra (ICD) cseréltük. Az 1 éves ICD-kontrollvizsgálat során azt találtuk, hogy a beültetés óta 22, tartós kamrai tachycardiával járó epizód lépett fel, melyek közül a készülék valamennyit sikeresen terminálta. Az eset bemutatásával szeretnénk rámutatni arra, hogy a magas cardiovascularis rizikócsoportba tartozó DM-betegek azonosítása kiemelkedő fontosságú lehet a hirtelen szívhalál megelőzése érdekében. Orv Hetil. 2021; 162(46): 1856-1858. Summary. Myotonic dystrophy (DM) is one of the most frequent adulthood diseases of the skeletal muscles, which develops multisystemic features and shows autosomal dominant trait. In DM, tissue degeneration affects not only the skeletal, but the cardiac muscle, too. In one third of the patients, the cause of death is of cardiac origin. We report on our patient's case, who was diagnosed with DM at the age of 52, in whom episodes of critical bradycardia with first-degree atrioventricular block was detected, resulting in a pacemaker implantation. Invasive cardiac electrophysiological study was performed, during which ventricular fibrillation was registered. A shock electrode was added to the previously implanted pacemaker, enabling defibrillation in case of detection of a sustained ventricular arrhythmia. During the 1-year follow-up, 22 episodes of sustained ventricular tachycardia were identified, with the device successfully terminating the malignant arrhythmias. Our case shows that electrophysiological study and the succeeding implantation of an implantable cardiac defibrillator is highly important in identifying and terminating ventricular arrhythmias in high-risk DM patients. Orv Hetil. 2021; 162(46): 1856-1858.

In search of lost time - a case of myocardial perforation in a patient with arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is particularly hard to diagnose and manage. We present the case of a 49-year-old, a former professional football player, with a history of cardiac arrest in 2011 by ventricular tachycardia (VT) (normal coronary arteries). Between 2011 and 2019 the patient didn't present for reevaluation and resumed endurance sports activity. In 2019 he was directed to our clinic for a syncope followed by constrictive anterior chest pain and palpitations, the clinical expression of a VT for which cardioversion was required. Upon admission, the patient was at sinus rhythm with negative T waves in V1-V2. Echocardiography showed significant dilatation and dysfunction of the RV (TAPSE 16 mm, FAC 20%, S' 8.6 cm/s). To confirm the diagnosis of ARVC, cardiac MRI was performed, confirming fat infiltration in the RV free wall with biventricular involvement. Given the high arrhythmic risk, a two-chamber ICD was implanted. In the second postprocedural day, the patient presented important epigastric pain, with ECG signs of sensing and pacing malfunction and ventricular probe displacement on the radioscopy. Emergency surgery was performed, with successful extraction of the electrode. Postoperative progression was favorable under treatment with beta-blocker and amiodarone. In conclusion, this case is a particular one since we’ve documented two distinct phases in the evolution of the ARVC (electrical phase – 2011 and structural phase - 2019). Moreover, by resuming endurance sports activity and in concordance with the literature data, we can only assume that the progression of the disease was accelerated, with a greater arrhythmic risk.

Fragmented QRS is associated with ventricular arrhythmias in heart failure patients: A systematic review and meta-analysis

INTRODUCTION

Many primary prevention heart failure (HF) patients with an implantable cardiac defibrillator (ICD) rarely experience life-threatening ventricular arrhythmias (VA). New strategies are required to identify patients most at risk of VA and sudden cardiac death who would benefit from an ICD. One potential method is the detection of fragmented QRS (fQRS) on the electrocardiogram. The aim was to assess the predictive capacity of fQRS for VA and mortality in ischemic (ICM) and non-ischemic cardiomyopathy (NICM) primary prevention HF patients.

METHODS AND RESULTS

A systematic review and meta-analysis of studies examining fQRS in HF patients with or without an ICD who met primary prevention indications with reduced ejection fraction ≤40%. Outcome measures were VA (or appropriate ICD therapy) and all-cause mortality. Ten studies involving 3885 patients were included for analysis. Most patients were male with non-fQRS patients being significantly younger (-1.5[-2.66, -0.42], p = .03). Diabetes was more likely in fQRS patients (1.12[1.01, 1.25], p = .03) while non-fQRS patients were 28% more likely to have a history of atrial fibrillation (0.82[0.67,1.00], p = .05). Ventricular arrhythmias were significantly 1.5 times more likely in patients with fQRS (1.51[1.02, 2.25], p = .04). HF patients were 1.7 times more likely to die of any cause if fQRS was present (1.68[1.13, 2.52], p = .01). NICM patients with fQRS have a significant 2.6-fold increased incidence of death compared with ICM patients (2.55[1.63, 3.98], p < .0001).

CONCLUSION

fQRS is associated with VA and all-cause mortality and may be a novel marker in the risk stratification of primary prevention HF patients indicated for ICD implantation.

The value of C-reactive protein-to-albumin ratio in predicting long-term mortality among HFrEF patients with implantable cardiac defibrillators

BACKGROUND

Patients with heart failure with reduced ejection fraction (HFrEF) who received implantable cardiac defibrillator (ICD) still remain at high risk due to pump failure and prevalent comorbid conditions. The primary aim of this research was to evaluate the predictive value of C-reactive protein-to-albumin ratio (CAR) for all-cause mortality among patients with HFrEF despite ICD implantation.

MATERIALS AND METHODS

Those who were implanted ICD for HFrEF in our institution between 2009 and 2019 were included. Data were extracted from hospital's database. CAR was calculated as ratio of C-reactive protein (CRP) to serum albumin concentration. Patients were grouped into tertiles in accordance with CAR at the time of the implantation. During follow-up duration of 38 [17-77] months, survival times of tertiles were compared by using Kaplan-Meier survival method. Forward Cox proportional regression model was used for multivariable analysis.

RESULTS

Thousand and eleven patients constituted the study population. Ischaemic cardiomyopathy was the primary diagnosis in 92.3%, and ICD was implanted for the primary prevention among 33.9% of patients. Of those, 14.5% died after the discharge. Patients in tertile 3 (T3) had higher risk of mortality (4.2% vs 11.0% vs 28.5%) compared with those in other tertiles. Multivariable analysis revealed that when patients in T1 were considered as the reference, both those in T2 and those in T3 had independently higher risk of all-cause mortality. This finding was consistent in the unadjusted and adjusted multivariable models.

CONCLUSION

Among patients with HFrEF and ICD, elevated CAR increased the risk of all-cause mortality at long term.

Impact of delayed device re-implantation on outcomes of patients with cardiovascular implantable electronic device related infective endocarditis

BACKGROUND

Optimal timing of cardiovascular implantable electronic device (CIED) re-implantation following device removal due to infection is undefined. Multinational guidelines reflect this and include no specific recommendation for this timing, while others have recommended waiting at least 14 days in cases of CIED related infective endocarditis (CIED-IE). The current work seeks to clarify this issue.

METHODS

We retrospectively reviewed institutional data at Mayo Clinic, Minnesota of patients aged ≥ 18 years who developed CIED-IE from January 1, 1991 to February 1, 2016. CIED-IE was defined as echocardiogram reported device lead or valvular vegetation. Regression analyses were used to relate the risk of clinical outcomes to the interval between CIED removal and re-implantation and the location of vegetations.

RESULTS

A total of 109 patients met study inclusion criteria. A majority (68.8%) of patients were men and the median age was 68.0 years. Transoesophageal echocardiogram (TEE) was performed in 95.4% of patients, with valve vegetations detected in 33.9% (n = 37). Survival analysis comparing patients in whom device re-implantation was < 14 days vs. ≥14 days, and further categorized by those with and without valve vegetation, showed a significant difference (P = 0.028); patients with valve vegetation and reimplantation interval < 14 days had the lowest (58.7%) 12-month survival. When adjusted for valve vegetation, longer time interval for reimplantation trended toward increased hospital length of stay (P = 0.079).

CONCLUSION

Our findings suggest that the recommended 14-day delay between CIED extraction and re-implantation in CIED-IE patients is associated with a survival benefit, but longer length of hospital stay following re-implantation.

Appropriate ICD Interventions for Ventricular Arrhythmias Are Predicted by Higher Syntax Scores I and II in Patients with Ischemic Heart Disease

Aims. The occurrence of ventricular arrhythmias (VAs) in ischemic heart disease (IHD) patients is related to the presence and extent of fibrotic/scar tissue. As coronary atherosclerosis is the underlying cause of myocardial ischemia and fibrosis, in IHD patients implanted with an implantable cardioverter defibrillator (ICD) we investigated the relation between the VA burden and the complexity of coronary atherosclerotic lesions. Methods and results. In IHD patients who underwent coronary angiography and ICD implant, the Syntax scores I and II (SSI-II), as index of the severity of the coronary atherosclerotic disease, and the occurrence of VA were assessed. Overall 144 patients were included (123 males). Of these 22 patients (15%) experienced at least one episode of VA (cycle length 298 ± 19 msec) that required ICD intervention. The number of episodes per patient and per year was 4 ± 6 and 2.8 ± 4, respectively. Patients that experienced a VA compared to those free from arrhythmic events did not have distinct baseline clinical characteristics except for a higher SS I and SS II (21 (IQR 13–38) vs. 16 (IQR 10–23); p = 0.037; and 50 (IQR 39–62) vs. 42 (IQR 34–50); p = 0.012). In the binary logistic regression analyses the SS I and II were the only independent predictors of VA occurrence. A higher SS II was also associated with an earlier time to first event (p = 0.005). Conclusion. Higher SS I-II scores reflect a more severe coronary atherosclerosis and are associated with a greater VA burden. Further studies are needed to better clarify the ability of SSI-II to stratify the risk of IHD patients to develop life-threatening VA.

Primary Prevention Implantable Cardiac Defibrillators: A Townsville District Perspective

Background: Despite major advances in treating patients with severe heart failure, deciding who should receive an implantable cardiac defibrillator (ICD) remains challenging.

Objective: To study the risk factors and mortality in patients after receiving an ICD (January 2008–December 2015) in a regional hospital in Australia.

Methods: Eighty-two primary prevention patients received an ICD for ischemic cardiomyopathy (ICM, n = 41) and non-ischemic cardiomyopathy (NICM, n = 40) with 4.8-yrs follow-up. One patient had mixed ICM/NICM indications. Ventricular arrhythmias were assessed using intracardiac electrograms. Statistical analysis compared the total population and ICM and NICM groups using Kaplan-Meier for survival, Cox regression for mortality predictors, and binary logistic regression for predictors of ventricular arrhythmias (p < 0.05).

Results: Major risk factors were hypercholesterolemia (70.7%), hypertension (47.6%), and obesity (41.5%). Severe obstructive sleep apnea (OSA) was found exclusively in NICM patients (23.7%, p = 0.001). Mortality was 30.5% after 4.8-yrs. The majority of patients (n=67) had no sustained ventricular arrhythmias yet 28% received therapy (n = 23), 18.51% were appropriate (n = 15), and 13.9% inappropriate (n = 11). Patients receiving ≥2 incidences of inappropriate shocks were 18-times more likely to die (p = 0.013). Three sudden cardiac deaths (SCD) (3.7%) were prevented by the ICD.

Conclusion: Patients implanted with an ICD in Townsville had 30.5% all-cause mortality after 4.8-yrs. Only 28% of patients received ICD therapy and 13.9% were inappropriate. OSA may have contributed to the fourfold increase in inappropriate therapy in NICM patients. Our study raises important efficacy, ethical and healthcare cost questions about who should receive an ICD, and possible regional and urban center disparities.

Long-Term Survival After Implantable Cardiac Defibrillator Therapy According to Sex: A Propensity Matched Study

Background: Whether the sex factor influences the benefit of the implantable cardioverter-defibrillator (ICD) for the prevention of sudden death remains a subject of debate. Using a prospective registry, we sought to analyze the survival and time to first ICD therapy according to sex. Materials and Methods: Retrospective analysis of a prospective cohort of patients undergoing an ICD implant from 2008 to 2019. Data about time to first appropriate therapy, type of therapy administered, and incidence and causes of mortality were collected. Results: Among 756 ICD patients, 150 (19.8%) were women. Women were younger (51 ± 15 years vs. 61 ± 14 years; p < 0.001) and showed a lower rate of ischemic cardiomyopathy (23% vs. 54%; p < 0.001) and atrial fibrillation (12% vs. 19%; p = 0.05). Women had higher left ventricular ejection fraction (39% ± 17% vs. 35% ± 13%) and showed more frequently left bundle branch block (39% vs. 28%, p = 0.027). The rate of primary prevention (68% vs. 59.6%; p = 0.058) and cardiac resynchronization therapy (27% vs. 19%, p = 0.02) were higher in women. After a median follow-up of 46 months (3382 patient-years), the incidence of both the primary combined endpoint of mortality/transplant (20% vs. 29%; logrank = 0.031) and ICD therapies (27% vs. 34%; p = 0.138) were lower in women. According to the propensity score-matching analysis, no differences were observed between both sexes with respect to the incidence of mortality/transplant (24.8% vs. 28.6%; logrank = 0.88), ICD therapies (28% vs. 27%; logrank = 0.17), and main cause of death (heart failure [HF]). Conclusions: The clinical characteristics at the moment of ICD implant are different between sexes. After adjusting them, both sexes equally benefit from the ICD. HF is the main cause of mortality both in men and women.

Implantation of cardiac defibrillator in an infant with hypertrophic cardiomyopathy and newly identified MYBP3 mutation

Hypertrophic cardiomyopathy has the highest incidence rate among genetically inherited cardiac diseases. It develops as a result of mutations in genes in related to the sarcomere protein in cardiac muscle. Generally, this results in asymmetrical hypertrophy. Patients who are symptomatic and have a significantly narrow left ventricular undergo should receive surgical treatment, whereas patients with a sudden cardiac death risk should receive treatment with an implantable cardiac defibrillator. This paper presents an infant with hypertrophic cardiomyopathy who was recently identified as having a mutation that resulted in a deletion-insertion type framework shift in the gene MYBPC3, who had family history of sudden death at a young age, and received myectomy and treatment with an implantable cardiac defibrillator in the same session due to a severely narrowed left ventricular outflow tract.

Inadvertent Disabling of Implantable Cardiac Defibrillator Antitachycardia Therapies Following Breast Reconstructive Surgery

A 47-year-old woman with an implantable cardiac defibrillator and breast cancer underwent left breast mastectomy with simultaneous reconstruction using a breast tissue expander. She was found to have intermittent disabling of tachyarrhythmia detection and therapy functions of her implantable cardiac defibrillator that were triggered by the breast tissue expander magnetic port. (Level of Difficulty: Beginner.)

Safety of bioelectrical impedance analysis in advanced heart failure patients

BACKGROUND

Cardiac cachexia and frailty are major complications of advanced heart failure (AHF). Bioelectrical impedance analysis (BIA) may provide valuable information regarding fluid balance, muscle mass and prognosis. The main concerns regarding the use of BIA in AHF patients remain arrhythmias and electromagnetic interferences with cardiac implantable electronic devices (CIEDs). Reliable data regarding patients on continuous-flow ventricular assist device (cf-VAD) remain scarce. The aim of this study is to evaluate the safety of BIA in AHF patients on pro-arrhythmogenic therapy with an implanted CIED and/or with a cf-VAD.

METHODS

We prospectively performed 217 BIA measurements in 143 AHF patients at risk of severe arrhythmias due to inotropic support/a history of ventricular arrhythmias and/or treated with CIED, including 104 patients with an ICD, CRT or pacemaker and 95 patients with a cf-VAD. All patients were under continuous Electrocardiogram (ECG) monitoring and clinical surveillance for 24 hours.

RESULTS

No adverse events were observed during the 217 BIA measurements: No rhythm disturbances were documented in the telemetric monitoring during or within 30 minutes after the measurement. CIEDs showed no malfunction, regardless of the location measured or the device manufacturer. In particular, no inappropriate shocks were observed. No alarms, flow disturbances, or malfunctions of the cf-VAD occurred during or after the measurements.

CONCLUSION

We consider BIA a safe measurement with major clinical relevance in our cohort of AHF patients, despite an increased arrhythmic potential on inotropic support or the presence of implanted electronic devices (ICD, CRT, pacemaker and cf-VAD).

Association between Arrhythmia and Pulmonary Artery Pressure in Heart Failure Patients Implanted with a Cardiac Defibrillator and Ambulatory Pulmonary Artery Pressure Sensor

The association between ventricular arrhythmia (VA) burden or defibrillator therapy and pulmonary artery pressure (PAP) has not been characterized in an ambulatory setting; thus, we sought in the present research to determine the relationship between ambulatory PAP and VA burden. A retrospective cohort study involving patients with an implantable cardiac defibrillator and CardioMEMS™ PAP sensor (Abbott Laboratories, Chicago, IL, USA) both transmitting remotely into the Merlin.net™ patient care network (Abbott Laboratories, Chicago, IL, USA) was conducted. VA and therapy burden in the six months following sensor implant were stratified by the baseline mean PAP. Patients with PAPs of 25 mmHg to 35 mmHg and those with PAPs of 35 mmHg or more were compared with individuals with PAPs of less than 25 mmHg. The change in VA burden was reported using the averaged mean PAP reduction during the first three months. A total of 162 patients aged 69.4 years ± 10.9 years were included (74% male) with a baseline mean PAP of 36.2 mmHg ± 10.4 mmHg. Twenty patients with a baseline mean PAP of less than 25 mmHg had no VAs over six months. For 61 patients with a baseline mean PAP of between 25 mmHg and 35 mmHg, the annualized number of days with ventricular tachycardia (VT)/ventricular fibrillation (VF) was 1.65/patient-year (p < 0.001), with 8% of patients having VT/VF events. For 81 patients with a baseline mean PAP of 35 mmHg or more, 19% of patients had a VT/VF event and an annualized number of days with VT/VF events of 1.45/patient-year (p < 0.001). When analyzing the treatment effect, a reduction of 3 mmHg or more in mean PAP over three months reduced arrhythmia burden over the next three months as compared with in patients without such an improvement. In conclusion, it is indicated that VAs are associated with high PAPs, and a reduction in PAP may lead to a reduction in VAs in real-world ambulatory patients.

Gender Differences in Rates of Arrhythmias, Cardiac Implantable Electronic Devices, and Diagnostic Modalities Among Sarcoidosis Patients

Introduction

Sarcoidosis is a granulomatous disease with multiorgan involvement. Cardiac involvement may be asymptomatic or present clinically as heart failure, arrhythmias, or even sudden cardiac death. In this study, we compared gender differences in the prevalence of arrhythmias and associated outcomes in patients with sarcoidosis without established coronary artery disease.

Methods

The United States Nationwide Inpatient Sample was queried from 2010 to 2014 to identify patients with sarcoidosis using the International Classification of Diseases, Ninth Revision (ICD-9) diagnosis code in patients >18 years. We excluded patients with a prior history of myocardial infarction, percutaneous coronary intervention, and coronary artery bypass graft. The chi-square test was used for statistical analysis.

Results

The sample consisted of 308,064 patients (mean age = 55.65 ± 11.28 years); they were mostly women (65.2%) and black (46.7%). In-hospital mortality in this cohort was 2.5%. The most common arrhythmia was atrial fibrillation (9.7%). The prevalence of ventricular fibrillation was 0.2%, ventricular tachycardia 2%, complete heart block 0.5%, and second-degree Mobitz type II (0.1%). Sudden cardiac death occurred in 0.7%. Rates of various cardiac devices implanted were: implantable cardiac defibrillator (ICD) (0.5%), cardiac resynchronization therapy-defibrillator (CRT-D) (0.2%), pacemaker (0.4%). Rates of endomyocardial biopsy (EMB), radionuclide imaging, and cardiac magnetic resonance imaging (MRI) were 0.2%, 0.3%, and 0.1%, respectively. Based on gender (male vs. female), the rates of arrhythmias, cardiac device implantation, and utilization of diagnostic modalities were: atrial fibrillation (41% vs 59%; p<0.001), ventricular fibrillation (50% vs 50%; p=0.983), ventricular tachycardia (55% vs 45%; p<0.001), complete heart block (48% vs 52%; p=0.3), second-degree Mobitz type II (37% vs 63%; p=0.706), sudden cardiac death (38% vs 62%; p<0.171), ICD (56% vs 44%; p<0.001), CRT-D (58% vs 42%; p=0.025), permanent pacemaker (40% vs 60%; p=0.066), EMB (55% vs 45%; p<0.001), radionuclide imaging (32% vs 68%; p=0.403), and cardiac MRI (41% vs 59%; p=0.396). In-hospital mortality was higher in females (64% vs 36%; p<0.001).

Conclusion

In our study, in-hospital death was more common in females. Females had higher rates of atrial fibrillation as compared to males, who were found to have a higher burden of ventricular tachycardia. Males had higher rates of ICD and CRT-D placement. Males also had EMB performed more commonly than females.

Sudden cardiac death: an update

Sudden cardiac death (SCD) is a devastating and all too common result of both acquired and genetic heart diseases. The profound sadness endured by families is compounded by the risk many of these deaths confer upon surviving relatives. For those with known cardiac disease, disease-specific therapy and risk stratification are key to reducing sudden death. For families of a SCD victim, uncovering a definitive cause of death can help relieve the agonising uncertainty and is a vital first step in screening surviving relatives and instituting therapy to reduce SCD risk. Increasing knowledge about the molecular mechanisms and genetic drivers of malignant arrhythmias in the diverse clinical entities that can cause SCD is vital if we are to optimise risk stratification and personalise patient care. Advances in diagnostic tools, disease-specific therapy and defibrillator technology are improving outcomes for patients and their families but there is still much progress to be made.

Phantom Model Testing of Active Implantable Cardiac Devices at 50/60 Hz Electric Field

Exposure to external extremely low-frequency (ELF) electric and magnetic fields induces the development of electric fields inside the human body, with their nature depending on multiple factors including the human body characteristics and frequency, amplitude, and wave shape of the field. The objective of this study was to determine whether active implanted cardiac devices may be perturbed by a 50 or 60 Hz electric field and at which level. A numerical method was used to design the experimental setup. Several configurations including disadvantageous scenarios, 11 implantable cardioverter-defibrillators, and 43 cardiac pacemakers were tested in vitro by an experimental bench test up to 100 kV/m at 50 Hz and 83 kV/m at 60 Hz. No failure was observed for ICNIRP public exposure levels for most configurations (in more than 99% of the clinical cases), except for six pacemakers tested in unipolar mode with maximum sensitivity and atrial sensing. The implants configured with a nominal sensitivity in the bipolar mode were found to be resistant to electric fields exceeding the low action levels, even for the highest action levels, as defined by the Directive 2013/35/EU. Bioelectromagnetics. 2020;41:136-147. © 2020 Bioelectromagnetics Society.

Cost-Effectiveness Analysis of Quadripolar Versus Bipolar Left Ventricular Leads for Cardiac Resynchronization Defibrillator Therapy in a Large, Multicenter UK Registry

OBJECTIVES

The objective of this study was to evaluate the cost-effectiveness of quadripolar versus bipolar cardiac resynchronization defibrillator therapy systems.

BACKGROUND

Quadripolar left ventricular (LV) leads for cardiac resynchronization therapy reduce phrenic nerve stimulation (PNS) and are associated with reduced mortality compared with bipolar leads.

METHODS

A total of 606 patients received implants at 3 UK centers (319 Q, 287 B), between 2009 and 2014; mean follow-up was 879 days. Rehospitalization episodes were costed at National Health Service national tariff rates, and EQ-5D utility values were applied to heart failure admissions, acute coronary syndrome events, and mortality data, which were used to estimate quality-adjusted life-year differences over 5 years.

RESULTS

Groups were matched with regard to age and sex. Patients with quadripolar implants had a lower rate of hospitalization than those with bipolar implants (42.6% vs. 55.4%; p = 0.002). This was primarily driven by fewer hospital readmissions for heart failure (51 [16%] vs. 75 [26.1%], respectively, for quadripolar vs. bipolar implants; p = 0.003) and generator replacements (9 [2.8%] vs. 19 [6.6%], respectively; p = 0.03). Hospitalization for suspected acute coronary syndrome, arrhythmia, device explantation, and lead revisions were similar. This lower health-care utilization cost translated into a cumulative 5-year cost saving for patients with quadripolar systems where the acquisition cost was <£932 (US $1,398) compared with bipolar systems. Probabilistic sensitivity analysis results mirrored the deterministic calculations. For the average additional price of £1,200 (US $1,800) over a bipolar system, the incremental cost-effective ratio was £3,692 per quality-adjusted life-year gained (US $5,538), far below the usual willingness-to-pay threshold of £20,000 (US $30,000).

CONCLUSIONS

In a UK health-care 5-year time horizon, the additional purchase price of quadripolar cardiac resynchronization defibrillator therapy systems is largely offset by lower subsequent event costs up to 5 years after implantation, which makes this technology highly cost-effective compared with bipolar systems.

Effect of coronary revascularization on long-term clinical outcomes in patients with ischemic cardiomyopathy and recurrent ventricular arrhythmia

BACKGROUND

Patients with ventricular tachycardia (VT) postmyocardial infarction (MI) are a higher risk group with significant morbidity and mortality. We examined the impact of prior coronary revascularization on clinical outcomes in patients with ischemic cardiomyopathy and VT.

METHODS

The VANISH trial randomized 259 patients with prior MI and antiarrhythmic drug-refractory VT to receive escalated medical therapy or catheter ablation. Clinical outcomes were compared according to whether patients have undergone prior revascularization procedures. The primary outcome was a composite of death, appropriate implantable cardiac defibrillator (ICD) shock, or VT storm. The secondary outcomes included elements of the primary outcome, hospitalization, and any ventricular arrhythmia.

RESULTS

190 patients (73%) had prior coronary revascularization. Revascularization group had more men (97% vs 83%; P  =  0.0003) and patients in that group were older (mean age 69.3 ± 7.6 vs 66.7 ± 9.2; P  =  0.04), had more renal insufficiency (22.6% vs 8.7%; P  =  0.01), and were more likely to have an implanted cardiac resynchronization device (23% vs 10%, P  =  0.03) as compared with the nonrevascularized patients. There were no significant differences in baseline medication use. There was a trend toward fewer hospitalizations in the revascularization group (64% vs 77%; P  =  0.07); there were no differences in the individual outcomes of mortality, VT storm, ICD shocks, recurrent MI, or cardiac failure.

CONCLUSIONS

In this cohort of patients with an ischemic cause for VT, a history of prior coronary revascularization was not associated with a reduction in ventricular arrhythmia or mortality.

Multiple inappropriate implantable cardiac defibrillator therapies in rapid succession

Inappropriate implantable cardiac defibrillator (ICD) shocks are associated with significant morbidity and have the potential to trigger ventricular arrhythmias, cardiac decompensation, and death. We present a case of multiple inappropriate ICD therapies in rapid succession due electromagnetic interference from a Dr‐Ho's transcutaneous electric nerve stimulator machine, and subsequently from a faulty electrical outlet.

Cardiovascular magnetic resonance-GUIDEd management of mild to moderate left ventricular systolic dysfunction (CMR GUIDE): Study protocol for a randomized controlled trial

BACKGROUND

The majority of sudden cardiac death (SCD) in patients with heart failure occurs in those with mild-moderate left ventricular (LV) systolic dysfunction (LVEF 36-50%) who under current guidelines are ineligible for primary prevention implantable cardiac defibrillator (ICD) therapy. Recent data suggest that cardiac magnetic resonance (CMR) evidence of replacement fibrosis forms a substrate for malignant arrhythmia and therefore potentially identifies a subgroup at increased risk of SCD. Our hypothesis is that among patients with mild-moderate LV systolic dysfunction, a CMR-guided management strategy for ICD insertion based on the presence of scar or fibrosis is superior to a current strategy of standard care.

METHODS/DESIGN

CMR GUIDE is a prospective, multicenter randomized control trial enrolling patients with mild-moderate LV systolic dysfunction and CMR evidence of fibrosis on optimal heart failure therapy. Participants will be randomized to receive either a primary prevention ICD or an implantable loop recorder (ILR). The primary endpoint is the time to SCD or hemodynamically significant ventricular arrhythmia (VF or VT) during an average 4-year follow-up. Secondary endpoints include quality of life assessed by Minnesota Living with Heart Failure Questionnaire, heart failure related hospitalizations, and a cost-utility analysis. Clinical trials.gov identifier NCT01918215.

DISCUSSION

CMR GUIDE trial will add substantially to our understanding of the role of myocardial fibrosis and the risk of developing life-threatening ventricular arrhythmias. If the superiority of a CMR-guided approach over standard care is proven, it may change international clinical guidelines, with the potential to considerably increase survival in this growing patient population.

Lessons Learned and Insights Gained in the Design, Analysis, and Outcomes of the COMPANION Trial

COMPANION (Comparison of Medical Therapy, Pacing and Defibrillation in Heart Failure), the first cardiac resynchronization therapy (CRT)-heart failure mortality and morbidity controlled clinical trial planned, conducted, and reported, was a randomized, 3-arm study that compared CRT delivered by a biventricular pacemaker (CRT-P) or a CRT defibrillator device (CRT-D) with optimal pharmacological therapy alone. The patient population had advanced chronic heart failure with QRS interval prolongation ≥120 ms and reduced left ventricular ejection fraction (heart failure with reduced ejection fraction). COMPANION had a composite hospitalization and mortality endpoint as the primary outcome measure but was also powered for mortality as the first secondary endpoint. The conduct of COMPANION was challenged by important issues that arose during the trial, the most important of which was U.S. Food and Drug Administration approval of CRT devices. Along with other challenges, this issue was appropriately dealt with by the Steering Committee and the Data and Safety Monitoring Committee and did not negatively affect trial results or conclusions. The authors report here updated analyses from the study, which are consistent with previously published results indicating that CRT-P or CRT-D has favorable effects on heart failure morbidity and mortality in a patient population "precision" selected by the surrogate marker of increased QRS interval duration. New analyses indicate that increasing the number of classes of neurohormonal inhibitor concurrent therapy has a positive effect on CRT mortality reduction. Hypothesis-generating new findings are that in patients receiving beta-blocker therapy, the mortality reduction advantage of CRT-D versus CRT-P may be minimized or eliminated and that there may be adverse effects of CRT-D defibrillator shocks on pump failure-related outcomes.

Large Controlled Observational Study on Remote Monitoring of Pacemakers and Implantable Cardiac Defibrillators: A Clinical, Economic, and Organizational Evaluation

Background

Patients with implantable devices such as pacemakers (PMs) and implantable cardiac defibrillators (ICDs) should be followed up every 3–12 months, which traditionally required in-clinic visits. Innovative devices allow data transmission and technical or medical alerts to be sent from the patient's home to the physician (remote monitoring). A number of studies have shown its effectiveness in timely detection and management of both clinical and technical events, and endorsed its adoption. Unfortunately, in daily practice, remote monitoring has been implemented in uncoordinated and rather fragmented ways, calling for a more strategic approach.

Objective

The objective of the study was to analyze the impact of remote monitoring for PM and ICD in a “real world” context compared with in-clinic follow-up. The evaluation focuses on how this service is carried out by Local Health Authorities, the impact on the cardiology unit and the health system, and organizational features promoting or hindering its effectiveness and efficiency.

Methods

A multi-center, multi-vendor, controlled, observational, prospective study was conducted to analyze the impact of remote monitoring implementation. A total of 2101 patients were enrolled in the study: 1871 patients were followed through remote monitoring of PM/ICD (I-group) and 230 through in-clinic visits (U-group). The follow-up period was 12 months.

Results

In-clinic device follow-ups and cardiac visits were significantly lower in the I-group compared with the U-group, respectively: PM, I-group = 0.43, U-group = 1.07, P<.001; ICD, I-group = 0.98, U-group = 2.14, P<.001. PM, I-group = 0.37, U-group = 0.85, P<.001; ICD, I-group = 1.58, U-group = 1.69, P=.01. Hospitalizations for any cause were significantly lower in the I-group for PM patients only (I-group = 0.37, U-group = 0.50, P=.005). There were no significant differences regarding use of the emergency department for both PM and ICD patients. In the I-group, 0.30 (PM) and 0.37 (ICD) real clinical events per patient per year were detected within a mean (SD) time of 1.18 (2.08) days. Mean time spent by physicians to treat a patient was lower in the I-group compared to the U-group (-4.1 minutes PM; -13.7 minutes ICD). Organizational analysis showed that remote monitoring implementation was rather haphazard and fragmented. From a health care system perspective, the economic analysis showed statistically significant gains (P<.001) for the I-group using PM.

Conclusions

This study contributes to build solid evidence regarding the usefulness of RM in detecting and managing clinical and technical events with limited use of manpower and other health care resources. To fully gain the benefits of RM of PM/ICD, it is vital that organizational processes be streamlined and standardized within an overarching strategy.

Video capsule endoscopy is successful and effective in outpatients with implantable cardiac devices

BACKGROUND AND AIM

Implantable cardiac devices are a relative contraindication to video capsule endoscopy (VCE) because of concerns regarding interference. As a result of a lack of alternatives, some centers have adopted protocols to allow for VCE in these patients. There are minimal published descriptions of the gastrointestinal outcomes of these procedures. We investigated the completion rate and diagnostic yield of VCE carried out in outpatients with implantable cardiac devices.

METHODS

We carried out a retrospective review of all VCE from April 2010 through March 2013 at our center. Patients that underwent VCE through a specialized protocol for outpatients with implantable cardiac devices were identified. The protocol used telemetry for cardiac monitoring during battery lifespan of the VCE. Demographic data, procedure indications, results and any procedural events were collected.

RESULTS

Twenty-one patients met the study criteria, with 16 (76%) pacemakers, four (19%) implantable cardioverter defibrilla tors and one (5%) implantable hemodynamic monitor. Two (10%) devices were adjusted prior to VCE. Twenty (95%) were completed to the colon, with a median gastric transit time of 18 min and a small bowel transit time of 216 min. The procedure was diagnostic in 13 (62%) patients. One (5%) capsule retention event occurred. No cardiac events or video capture disturbances occurred.

CONCLUSIONS

Video capsule endoscopy done on outpatients with implantable cardiac devices through a cardiac monitoring protocol resulted in a satisfactory completion rate and high diagnostic yield with no adverse cardiac events. A large prospective trial is needed to confirm these novel results.

Association of time of occurrence of electrical heart storms with environmental physical activity

AIM

Many publications in recent decades have reported a temporal link between medical events and environmental physical activity. The aim of this study was to analyze the time of occurrence of electrical heart storms against levels of cosmological parameters.

METHODS

The sample included 82 patients (71 male) with ischemic cardiomyopathy treated with an implantable cardioverter defibrillator at a tertiary medical center in 1999-2012 (5,114 days). The time of occurrence of all electrical heart storms, defined as three or more events of ventricular tachycardia or ventricular fibrillation daily, was recorded from the defibrillator devices. Findings were analyzed against data on solar, geomagnetic, and cosmic ray (neutron) activity for the same time period obtained from space institutions in the United States and Russia.

RESULTS

Electrical storms occurred in all months of the year, with a slight decrease in July, August, and September. Most events took place on days with lower-than-average levels of solar and geomagnetic activity and higher-than-average levels of cosmic ray (neutron) activity. There was a significant difference in mean daily cosmic ray activity between the whole observation period and the days of electrical storm activity (P = 0.0001).

CONCLUSION

These data extend earlier findings on the association of the timing of cardiac events and space weather parameters to the most dangerous form of cardiac arrhythmia-electric storms. Further studies are needed to delineate the pathogenetic mechanism underlying this association.

Cardiac positron emission tomography enhances prognostic assessments of patients with suspected cardiac sarcoidosis

OBJECTIVES

This study sought to relate imaging findings on positron emission tomography (PET) to adverse cardiac events in patients referred for evaluation of known or suspected cardiac sarcoidosis.

BACKGROUND

Although cardiac PET is commonly used to evaluate patients with suspected cardiac sarcoidosis, the relationship between PET findings and clinical outcomes has not been reported.

METHODS

We studied 118 consecutive patients with no history of coronary artery disease, who were referred for PET, using [(18)F]fluorodeoxyglucose (FDG) to assess for inflammation and rubidium-82 to evaluate for perfusion defects (PD), following a high-fat/low-carbohydrate diet to suppress normal myocardial glucose uptake. Blind readings of PET data categorized cardiac findings as normal, positive PD or FDG, positive PD and FDG. Images were also used to identify whether findings of extra-cardiac sarcoidosis were present. Adverse events (AE)-death or sustained ventricular tachycardia (VT)-were ascertained by electronic medical records, defibrillator interrogation, patient questionnaires, and telephone interviews.

RESULTS

Among the 118 patients (age 52 ± 11 years; 57% males; mean ejection fraction: 47 ± 16%), 47 (40%) had normal and 71 (60%) had abnormal cardiac PET findings. Over a median follow-up of 1.5 years, there were 31 (26%) adverse events (27 VT and 8 deaths). Cardiac PET findings were predictive of AE, and the presence of both a PD and abnormal FDG (29% of patients) was associated with hazard ratio of 3.9 (p < 0.01) and remained significant after adjusting for left ventricular ejection fraction (LVEF) and clinical criteria. Extra-cardiac FDG uptake (26% of patients) was not associated with AE.

CONCLUSIONS

The presence of focal PD and FDG uptake on cardiac PET identifies patients at higher risk of death or VT. These findings offer prognostic value beyond Japanese Ministry of Health and Welfare clinical criteria, the presence of extra-cardiac sarcoidosis and LVEF.

Regional myocardial sympathetic denervation predicts the risk of sudden cardiac arrest in ischemic cardiomyopathy. J Am Coll Cardiol. 2014;63:141-149. [PMID: 24076296 DOI: 10.1016/j.jacc.2013.07.096]

OBJECTIVES

The PAREPET (Prediction of ARrhythmic Events with Positron Emission Tomography) study sought to test the hypothesis that quantifying inhomogeneity in myocardial sympathetic innervation could identify patients at highest risk for sudden cardiac arrest (SCA).

BACKGROUND

Left ventricular ejection fraction (LVEF) is the only parameter identifying patients at risk of SCA who benefit from an implantable cardiac defibrillator (ICD).

METHODS

We prospectively enrolled 204 subjects with ischemic cardiomyopathy (LVEF ≤35%) eligible for primary prevention ICDs. Positron emission tomography (PET) was used to quantify myocardial sympathetic denervation ((11)C-meta-hydroxyephedrine [(11)C-HED]), perfusion ((13)N-ammonia) and viability (insulin-stimulated (18)F-2-deoxyglucose). The primary endpoint was SCA defined as arrhythmic death or ICD discharge for ventricular fibrillation or ventricular tachycardia >240 beats/min.

RESULTS

After 4.1 years follow-up, cause-specific SCA was 16.2%. Infarct volume (22 ± 7% vs. 19 ± 9% of left ventricle [LV]) and LVEF (24 ± 8% vs. 28 ± 9%) were not predictors of SCA. In contrast, patients developing SCA had greater amounts of sympathetic denervation (33 ± 10% vs. 26 ± 11% of LV; p = 0.001) reflecting viable, denervated myocardium. The lower tertiles of sympathetic denervation had SCA rates of 1.2%/year and 2.2%/year, whereas the highest tertile had a rate of 6.7%/year. Multivariate predictors of SCA were PET sympathetic denervation, left ventricular end-diastolic volume index, creatinine, and no angiotensin inhibition. With optimized cut-points, the absence of all 4 risk factors identified low risk (44% of cohort; SCA <1%/year); whereas ≥2 factors identified high risk (20% of cohort; SCA ∼12%/year).

CONCLUSIONS

In ischemic cardiomyopathy, sympathetic denervation assessed using (11)C-HED PET predicts cause-specific mortality from SCA independently of LVEF and infarct volume. This may provide an improved approach for the identification of patients most likely to benefit from an ICD. (Prediction of ARrhythmic Events With Positron Emission Tomography [PAREPET]; NCT01400334).

A Kinetics and Equilibrium Study of Vanadium Dissolution from Vanadium Oxides and Phosphates in Battery Electrolytes: Possible Impacts on ICD Battery Performance

Silver vanadium oxide (Ag₂V₄O₁₁, SVO) has enjoyed widespread commercial success over the past 30 years as a cathode material for implantable cardiac defibrillator (ICD) batteries. Recently, silver vanadium phosphorous oxide (Ag₂VO₂PO₄, SVPO) has been studied as possibly combining the desirable thermal stability aspects of LiFePO₄ with the electrical conductivity of SVO. Further, due to the noted insoluble nature of most phosphate salts, a lower material solubility of SVPO relative to SVO is anticipated. Thus, the first vanadium dissolution studies of SVPO in battery electrolyte solutions are described herein. The equilibrium solubility of SVPO was ~5 times less than SVO, with a rate constant of dissolution ~3.5 times less than that of SVO. The vanadium dissolution in SVO and SVPO can be adequately described with a diffusion layer model, as supported by the Noyes-Whitney equation. Cells prepared with vanadium-treated anodes displayed higher AC impedance and DC resistance relative to control anodes. These data support the premise that SVPO cells are likely to exhibit reduced cathode solubility and thus less affected by increased cell resistance due to cathode solubility compared to SVO based cells.

Successful delivery by a cesarean section in a parturient with severe dilated cardiomyopathy, an implantable cardioverter defibrillator, and a repaired tetralogy of fallot

Repaired congenital heart disease has become more prevalent in women of childbearing age. We report an unusual case of a 24-year-old multigravida with a repaired tetralogy of Fallot, severe dilated cardiomyopathy, and implantable cardioverter defibrillator placement who was managed successfully by a cesarean section three times. This case underscores the impact of such events on maternal and fetal safety and the importance of a multidisciplinary approach in the management of pregnant patients with complex congenital and medical problems.