Medical therapy versus implantable cardioverter -defibrillator in preventing sudden cardiac death in patients with left ventricular systolic dysfunction and heart failure: A meta-analysis of >35,000 patients

MR-Safe Cartesian Platform for Active Cardiac Shimming: Preliminary Validation

OBJECTIVE

Implanted Cardioverter Defibrillators (ICDs) induce a large (100 parts per million) inhomogeneous magnetic field in the magnetic resonance imaging (MRI) scanner which cannot be corrected by the scanner's built-in shim coils, leading to significant image artifacts that can make portions of the heart unreadable. To compensate for the field inhomogeneity, an active shim coil capable of countering the field deviation in user-defined regions was designed that must be optimally placed at patient-specific locations. We aim to develop and evaluate an MR-safe robotic solution for automated shim coil positioning.

METHODS

We designed and fabricated an MR-safe Cartesian platform that holds the shim coil inside the scanner. The platform consists of three lead screw stages actuated by pneumatic motors, achieving decoupled translations of 140 mm in each direction. The platform is made of plastics and fiberglass with the control electronics placed outside the scanner room, ensuring MR safety. Mechanical modeling was derived to provide design specifications.

RESULTS

Experiments show that the platform achieves less than 2 mm average motion error and 0.5 mm repeatability in all directions, and reduces the adjustment time from 5 min to a few seconds. Phantom and animal trials were conducted, showing that the proposed system is able to position a heavy shim coil ( kg) for improved ICD artifact suppression.

CONCLUSION

This robotic platform provides an effective method for reliable shim coil positioning inside the scanner.

SIGNIFICANCE

This work contributes to improving cardiac MRI quality that could facilitate accurate diagnosis and treatment planning for patients with implanted ICDs.

Balanced-force shim system for correcting magnetic-field inhomogeneities in the heart due to implanted cardioverter defibrillators

Background

In the US, 1.4 million people have implanted ICDs for reducing the risk of sudden death due to ventricular arrhythmias. Cardiac MRI (cMR) is of particular interest in the ICD patient population as cMR is the optimal imaging modality for distinguishing cardiac conditions that predispose to sudden death, and it is the best method to plan and guide therapy. However, all ICDs contain a ferromagnetic transformer which imposes a large inhomogeneous magnetic field in sections of the heart, creating large image voids that can mask important pathology. A shim system was devised to resolve these ICD issues. A shim coil system (CSS) that corrects ICD artifacts over a user-selected Region-of-Interest (ROI), was constructed and validated.

Methods

A shim coil was constructed that can project a large magnetic field for distances of ~15 cm. The shim-coil can be positioned safely anywhere within the scanner bore. The CSS includes a cantilevered beam to hold the shim coil. Remotely controlled MR-conditional motors allow 2 mm-accuracy three-dimensional shim-coil position. The shim coil is located above the subjects and the imaging surface-coils. Interaction of the shim coil with the scanner's gradients was eliminated with an amplifier that is in a constant current mode. Coupling with the scanners' radio-frequency (rf) coils, was reduced with shielding, low-pass filters, and cable shield traps. Software, which utilizes magnetic field (B0) mapping of the ICD inhomogeneity, computes the optimal location for the shim coil and its corrective current. ECG gated single- and multiple-cardiac-phase 2D GRE and SSFP sequences, as well as 3D ECG-gated respiratory-navigated IR-GRE (LGE) sequences were tested in phantoms and N = 3 swine with overlaid ICDs.

Results

With all cMR sequences, the system reduced artifacts from >100 ppm to <25 ppm inhomogeneity, which permitted imaging of the entire left ventricle in swine with ICD-related voids. Continuously acquired Gradient recalled echo or Steady State Free Precession images were used to interactively adjust the shim current and coil location.

Conclusion

The shim system reduced large field inhomogeneities due to implanted ICDs and corrected most ICD-related image distortions. Externally-controlled motorized translation of the shim coil simplified its utilization, supporting an efficient cardiac MRI workflow.

Risk and Protective Factors for Sudden Cardiac Death: An Umbrella Review of Meta-Analyses

Background

Sudden cardiac death (SCD) is a global public health issue, accounting for 10–20% of deaths in industrialized countries. Identification of modifiable risk factors may reduce SCD incidence.

Methods

This umbrella review systematically evaluates published meta-analyses of observational and randomized controlled trials (RCT) for the association of modifiable risk and protective factors of SCD.

Results

Fifty-five meta-analyses were included in the final analysis, of which 31 analyzed observational studies and 24 analyzed RCTs. Five associations of meta-analyses of observational studies presented convincing evidence, including three risk factors [diabetes mellitus (DM), smoking, and early repolarization pattern (ERP)] and two protective factors [implanted cardiac defibrillator (ICD) and physical activity]. Meta-analyses of RCTs identified five protective factors with a high level of evidence: ICDs, mineralocorticoid receptor antagonist (MRA), beta-blockers, and sodium-glucose cotransporter-2 (SGLT-2) inhibitors in patients with HF. On the contrary, other established, significant protective agents [i.e., amiodarone and statins along with angiotensin-converting enzyme (ACE) inhibitors in heart failure (HF)], did not show credibility. Likewise, risk factors as left ventricular ejection fraction in HF, and left ventricular hypertrophy, non-sustain ventricular tachycardia, history of syncope or aborted SCD in pediatric patients with hypertrophic cardiomyopathy, presented weak or no evidence.

Conclusions

Lifestyle risk factors (physical activity, smoking), comorbidities like DM, and electrocardiographic features like ERP constitute modifiable risk factors of SCD. Alternatively, the use of MRA, beta-blockers, SGLT-2 inhibitors, and ICD in patients with HF are credible protective factors. Further investigation targeted in specific populations will be important for reducing the burden of SCD.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020216363, PROSPERO CRD42020216363.

Outcomes of Digital Biomarker-Based Interventions: Protocol for a Systematic Review of Systematic Reviews

BACKGROUND

Digital biomarkers are defined as objective, quantifiable, physiological, and behavioral data that are collected and measured using digital devices such as portables, wearables, implantables, or digestibles. For their widespread adoption in publicly financed health care systems, it is important to understand how their benefits translate into improved patient outcomes, which is essential for demonstrating their value.

OBJECTIVE

The paper presents the protocol for a systematic review that aims to assess the quality and strength of the evidence reported in systematic reviews regarding the impact of digital biomarkers on clinical outcomes compared to interventions without digital biomarkers.

METHODS

A comprehensive search for reviews from 2019 to 2020 will be conducted in PubMed and the Cochrane Library using keywords related to digital biomarkers and a filter for systematic reviews. Original full-text English publications of systematic reviews comparing clinical outcomes of interventions with and without digital biomarkers via meta-analysis will be included. The AMSTAR-2 tool will be used to assess the methodological quality of these reviews. To assess the quality of evidence, we will evaluate the systematic reviews using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. To detect the possible presence of reporting bias, we will determine whether a protocol was published prior to the start of the studies. A qualitative summary of the results by digital biomarker technology and outcomes will be provided.

RESULTS

This protocol was submitted before data collection. Search, screening, and data extraction will commence in December 2021 in accordance with the published protocol.

CONCLUSIONS

Our study will provide a comprehensive summary of the highest level of evidence available on digital biomarker interventions, providing practical guidance for health care providers. Our results will help identify clinical areas in which the use of digital biomarkers has led to favorable clinical outcomes. In addition, our findings will highlight areas of evidence gaps where the clinical benefits of digital biomarkers have not yet been demonstrated.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/28204.

Cardiac arrhythmias in the emergency settings of acute coronary syndrome and revascularization: an European Heart Rhythm Association (EHRA) consensus document, endorsed by the European Association of Percutaneous Cardiovascular Interventions (EAPCI), and European Acute Cardiovascular Care Association (ACCA)

Despite major therapeutic advances over the last decades, complex supraventricular and ventricular arrhythmias (VAs), particularly in the emergency setting or during revascularization for acute myocardial infarction (AMI), remain an important clinical problem. Although the incidence of VAs has declined in the hospital phase of acute coronary syndromes (ACS), mainly due to prompt revascularization and optimal medical therapy, still up to 6% patients with ACS develop ventricular tachycardia and/or ventricular fibrillation within the first hours of ACS symptoms. Despite sustained VAs being perceived predictors of worse in-hospital outcomes, specific associations between the type of VAs, arrhythmia timing, applied treatment strategies and long-term prognosis in AMI are vague. Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia that may be asymptomatic and/or may be associated with rapid haemodynamic deterioration requiring immediate treatment. It is estimated that over 20% AMI patients may have a history of AF, whereas the new-onset arrhythmia may occur in 5% patients with ST elevation myocardial infarction. Importantly, patients who were treated with primary percutaneous coronary intervention for AMI and developed AF have higher rates of adverse events and mortality compared with subjects free of arrhythmia. The scope of this position document is to cover the clinical implications and pharmacological/non-pharmacological management of arrhythmias in emergency presentations and during revascularization. Current evidence for clinical relevance of specific types of VAs complicating AMI in relation to arrhythmia timing has been discussed.

Influence of Multimorbidity on Burden and Appropriateness of Implantable Cardioverter-Defibrillator Therapies

OBJECTIVE

To determine whether burden of multiple chronic conditions (MCCs) influences the risk of receiving inappropriate vs appropriate device therapies.

DESIGN

Retrospective cohort study.

SETTING

Seven US healthcare delivery systems.

PARTICIPANTS

Adults with left ventricular systolic dysfunction receiving an implantable cardioverter-defibrillator (ICD) for primary prevention.

MEASUREMENTS

Data on 24 comorbid conditions were captured from electronic health records and categorized into quartiles of comorbidity burden (0-3, 4-5, 6-7 and 8-16). Incidence of ICD therapies (shock and antitachycardia pacing [ATP] therapies), including appropriateness, was collected for 3 years after implantation. Outcomes included time to first ICD therapy, total ICD therapy burden, and risk of inappropriate vs appropriate ICD therapy.

RESULTS

Among 2235 patients (mean age = 69 ± 11 years, 75% men), the median number of comorbidities was 6 (interquartile range = 4-8), with 98% having at least two comorbidities. During a mean 2.2 years of follow-up, 18.3% of patients experienced at least one appropriate therapy and 9.9% experienced at least one inappropriate therapy. Higher comorbidity burden was associated with an increased risk of first inappropriate therapy (adjusted hazard ratio [HR] = 1.94 [95% confidence interval {CI} = 1.14-3.31] for 4-5 comorbidities; HR = 2.25 [95% CI = 1.25-4.05] for 6-7 comorbidities; and HR = 2.91 [95% CI = 1.54-5.50] for 8-16 comorbidities). Participants with 8-16 comorbidities had a higher total burden of ICD therapy (adjusted relative risk [RR] = 2.12 [95% CI = 1.43-3.16]), a higher burden of inappropriate therapy (RR = 3.39 [95% CI = 1.67-6.86]), and a higher risk of receiving inappropriate vs appropriate therapy (RR = 1.74 [95% CI = 1.07-2.82]). Comorbidity burden was not significantly associated with receipt of appropriate ICD therapies. Patterns were similar when separately examining shock or ATP therapies.

CONCLUSIONS

In primary prevention ICD recipients, MCC burden was independently associated with an increased risk of inappropriate but not appropriate device therapies. Comorbidity burden should be considered when engaging patients in shared decision making about ICD implantation.

Beta-Blockers and ACE Inhibitors Are Associated with Improved Survival Secondary to Ventricular Tachyarrhythmia

OBJECTIVE

The study sought to assess the impact of treatment with beta-blocker (BB) or ACE inhibitor/angiotensin receptor blocker (ACEi/ARB) on secondary survival in patients presenting with ventricular tachyarrhythmia.

BACKGROUND

Data regarding outcome of patients presenting with ventricular tachyarrhythmia treated with BB and ACEi/ARB is limited.

METHODS

A large retrospective registry was used including consecutive patients presenting with ventricular tachycardia and fibrillation from 2002 to 2016 on admission. Applying propensity-score matching for harmonization, the impact of "BB" and "ACEi/ARB" was comparatively evaluated. The primary prognostic outcome was long-term all-cause death at 3 years.

RESULTS

A total of 972 matched patients were included. Both patients with BB (long-term mortality rate 18 versus 27%; log rank p = 0.041; HR = 0.661; 95% CI = 0.443-0.986; p = 0.043) and with ACEi/ARB (long-term mortality rate 13 versus 23%; log rank p = 0.004; HR = 0.544; 95% CI = 0.359-0.824; p = 0.004) revealed better secondary survival compared to patients without after presenting with ventricular tachyarrhythmia on admission. The prognostic benefit of BB was comparable to ACEi/ARB (long-term mortality rate 21 versus 26%; log rank p = 0.539).

CONCLUSION

BB and ACEi/ARB were associated with improved secondary survival in patients surviving ventricular tachyarrhythmia on admission.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02982473.

Recent advances in the management of ventricular tachyarrhythmias

Ventricular arrhythmias are an important cause of cardiovascular morbidity and mortality, particularly in those with structural heart disease, inherited cardiomyopathies, and channelopathies. The goals of ventricular arrhythmia management include symptom relief, improving quality of life, reducing implantable cardioverter defibrillator shocks, preventing deterioration of left ventricular function, reducing risk of arrhythmic death, and potentially improving overall survival. Guideline-directed medical therapy and implantable cardioverter defibrillator implantation remain the mainstay of therapy to prevent sudden cardiac death in patients with ventricular arrhythmias in the setting of structural heart disease. Recent advances in imaging modalities and commercial availability of genetic testing panels have enhanced our mechanistic understanding of the disease processes and, along with significant progress in catheter-based ablative therapies, have enabled a tailored and more effective management of drug-refractory ventricular arrhythmias. Several gaps in our knowledge remain and require further research. In this article, we review the recent advances in the diagnosis and management of ventricular arrhythmias.

Health Insurance Expansion and Incidence of Out-of-Hospital Cardiac Arrest: A Pilot Study in a US Metropolitan Community

BACKGROUND

Health insurance has many benefits including improved financial security, greater access to preventive care, and better self-perceived health. However, the influence of health insurance on major health outcomes is unclear. Sudden cardiac arrest prevention represents one of the major potential benefits from health insurance, given the large impact of sudden cardiac arrest on premature death and its potential sensitivity to preventive care.

METHODS AND RESULTS

We conducted a pre-post study with control group examining out-of-hospital cardiac arrest (OHCA) among adult residents of Multnomah County, Oregon (2015 adult population 636 000). Two time periods surrounding implementation of the Affordable Care Act were evaluated: 2011-2012 ("pre-expansion") and 2014-2015 ("postexpansion"). The change in OHCA incidence for the middle-aged population (45-64 years old) exposed to insurance expansion was compared with the elderly population (age ≥65 years old) with constant near-universal coverage. Rates of OHCA among middle-aged individuals decreased from 102 per 100 000 (95% CI: 92-113 per 100 000) to 85 per 100 000 (95% CI: 76-94 per 100 000), P value 0.01. The elderly population experienced no change in OHCA incidence, with rates of 275 per 100 000 (95% CI: 250-300 per 100 000) and 269 per 100 000 (95% CI: 245-292 per 100 000), P value 0.70.

CONCLUSIONS

Health insurance expansion was associated with a significant reduction in OHCA incidence. Based on this pilot study, further investigation in larger populations is warranted and feasible.

Improving Heart Failure Outcomes: The Role of the Clinical Nurse Specialist

This article identifies and explains barriers to optimal outcomes of heart failure and the role of the clinical nurse specialist in overcoming these obstacles, improving patient outcomes and quality of life. In recent years, advances in heart failure management have increased survival rates, and as a result, the number of patients requiring services to manage disease progression and the complex array of symptoms associated with end-stage heart disease. Management of the heart failure patient is dependent on the severity of the disease and wide range of available treatment regimens. Disease progression can be unpredictable and treatment regimens increasingly complex. The authors present a typical case of a patient with heart failure, identify the barriers to optimal outcomes in managing heart failure, as well as describe the roles of the clinical nurse specialist in overcoming these barriers within 3 spheres of clinical nurse specialist influence: patient, health care provider, and health care systems. The clinical nurse specialist role is ideally suited to positively affect heart failure outcomes. These positive effects are drawn from the dynamic and unique nature of the clinical nurse specialist role and are perpetrated through the 3 spheres of clinical nurse specialist practice: patient, health care provider, and heath care system.

Prehospital Predictors of Initial Shockable Rhythm in Out-of-Hospital Cardiac Arrest: Findings From the Taichung Sudden Unexpected Death Registry (THUNDER)

OBJECTIVE

To identify the incidence and prehospital predictors of ventricular tachycardia/ventricular fibrillation (VT/VF) as the initial arrhythmia in patients with out-of-hospital cardiac arrest (OHCA) in central Taiwan.

PATIENTS AND METHODS

The Taichung Sudden Unexpected Death Registry program encompasses the Taichung metropolitan area in central Taiwan, with a population of 2.7 million and 17 destination hospitals for patients with OHCA. We performed a detailed analysis of demographic characteristics, circumstances of cardiac arrest, and emergency medical service records using the Utstein Style.

RESULTS

From May 1, 2013, through April 30, 2014, resuscitation was attempted in 2013 individuals with OHCA, of which 384 were excluded due to trauma and noncardiac etiologies. Of the 1629 patients with presumed cardiogenic OHCA, 7.9% (n=129) had initial shockable rhythm; this proportion increased to 18.8% (61 of 325) in the witnessed arrest subgroup. Male sex (odds ratio [OR], 2.45; 95% CI, 1.46-4.12; P<.001), age younger than 65 years (OR, 2.39, 95% CI, 1.58-3.62; P<.001), public location of arrest (OR, 4.61; 95% CI, 2.86-7.44; P<.001), and witnessed status (OR, 3.98; 95% CI, 2.62-6.05; P<.001) were independent predictors of VT/VF rhythm.

CONCLUSION

The proportion of patients with OHCA presenting with VT/VF was generally low in this East Asian population. Of the prehospital factors associated with VT/VF, public location of OHCA was the strongest predictor of VT/VF in this population, which may affect planning and deployment of emergency medical services in central Taiwan.