Appropriate Evaluation and Treatment of Heart Failure Patients After Implantable Cardioverter-Defibrillator Discharge

Acute pathophysiological myocardial changes following intra-cardiac electrical shocks using a proteomic approach in a sheep model

Implantable cardioverter-defibrillators (ICD) are meant to fight life-threatening ventricular arrhythmias and reduce overall mortality. Ironically, life-saving shocks themselves have been shown to be independently associated with an increased mortality. We sought to identify myocardial changes at the protein level immediately after ICD electrical shocks using a proteomic approach. ICD were surgically implanted in 10 individuals of a healthy male sheep model: a control group (N = 5) without any shock delivery and a shock group (N = 5) with the delivery of 5 consecutive shocks at 41 J. Myocardial tissue samples were collected at the right-ventricle apex near to the lead coil and at the right ventricle basal free wall region. Global quantitative proteomics experiments on myocardial tissue samples were performed using mass spectrometry techniques. Proteome was significantly modified after electrical shock and several mechanisms were associated: protein, DNA and membrane damages due to extreme physical conditions induced by ICD-shock but also due to regulated cell death; metabolic remodeling; oxidative stress; calcium dysregulation; inflammation and fibrosis. These proteome modifications were seen in myocardium both "near" and "far" from electrical shock region. N-term acetylated troponin C was an interesting tissular biomarker, significantly decreased after electrical shock in the "far" region (AUC: 0.93). Our data support an acute shock-induced myocardial tissue injury which might be involved in acute paradoxical deleterious effects such as heart failure and ventricular arrhythmias.

Inappropriate implantable cardioverter-defibrillator shocks in repaired tetralogy of fallot patients: Prevalence and electrophysiological mechanisms

Background

Patients with Tetralogy of Fallot (TOF) are at increased risk for sudden cardiac death, often undergo implantable cardioverter defibrillator (ICD) implantation at younger ages, and are at greater risk of experiencing inappropriate shocks. We investigated occurrences of ICD shocks in TOF patients to identify prevalence, characteristics associated with inappropriate shocks, and therapeutic interventions after inappropriate shocks.

Methods

Records of patients with repaired TOF and ICD implantation who were followed at Columbia University Irving Medical Center between 1/1/2000 and 5/1/2019 were analyzed.

Results

44 patients with repaired TOF and ICD implantation were reviewed. Mean age at implantation was 39 ± 13 years. Eight (18%) patients received both appropriate and inappropriate shocks, 6 (14%) received only appropriate shocks, and 3 (7%) received only inappropriate shocks. Three patients received inappropriate shocks for sinus tachycardia, 7 for atrial arrhythmias, and 1 for noise artifact. Inappropriately shocked patients had lower beat per minute (bpm) cutoff values for ICD therapy (mean = 162 ± 24 bpm vs. 182 ± 16 bpm, p = 0.007). After inappropriate shocks, 1 patient underwent lead replacement, 1 had the VT cutoff increased, and 6 were treated with medications.

Conclusions

One quarter of TOF patients with ICDs experienced inappropriate shock therapy, the timing of which was most often clustered within the first two years after implant or years later. Lower shock therapy zones were associated with increased risk for inappropriate shocks, and the majority of inappropriate shocks resulted from atrial arrhythmias with rapid ventricular response. Treatments for inappropriate shocks included increasing VT therapy bpm and rhythm and/or rate control medications.

Reduced occurrence of appropriate therapy for ventricular arrhythmias after beta-blocker uptitration following implant of a primary prevention CRT-defibrillator

Background: Absence of beta-blocker use independently predicts appropriate therapy. Following cardiac resynchronisation therapy (CRT) implant, reverse remodelling and protection against bradycardia allows for beta-blocker dose uptitration. The differential dosing effects on the occurrence of a first episode of appropriate therapy in primary prevention CRT-defibrillator (CRT-D) patients remains unstudied.Methods and Results: Changes in beta-blocker dose following CRT-D in consecutive primary prevention patients implanted between 2008 and 2015 were retrospectively studied. Beta-blocker dose was expressed as percent of target dose. Uptitration of beta-blocker dose following implant was calculated as the change in percent of target dose between implant and 6-months follow-up. Results from a prospectively maintained database of all device analysis were used to determine the occurrence of appropriate therapy. A total of 162 patients (68 ± 8 years) were studied. One hundred and ten (68%) patients underwent uptitration (mean 47 ± 19% in target dose) and 52 (32%) remained on a stable beta-blocker dose. During 37 ± 22 months follow-up, the cumulative percent of appropriate therapy was 31% in patient receiving no-uptitration versus 10% in the uptitrated patients (p < 0.001). After correction for known predictors of appropriate therapy, uptitration was independently associated with an OR = 0.263 (CI = 0.103-0.675; p = 0.001) for the occurrence of appropriate therapy. Every 1%-increase in target dose for beta-blocker associated with a significant lower risk for appropriate therapy, OR = 0.982 (CI = 0.965-0.999; p = 0.042).Conclusion: Following implantation of a primary prevention CRT-D, uptitration of beta-blockers associated with a reduced occurrence of a first episode of appropriate therapy for ventricular arrhythmias. An inverse dose-response effect was seen between beta-blocker dose and appropriate therapy.

Arrhythmic episodes in patients implanted with a cardioverter-defibrillator - results from the Prospective Study on Predictive Quality with Preferencing PainFree ATP therapies (4P)

Background

Little is known about the ICD performance using enhanced detection algorithms in unselected, non-trial patients. Performance of recent generation ICD equipped with SmartShock™ technology (SST) for detection and conversion of ventricular tachyarrhythmias (VTA) was investigated.

Methods

4P was a prospective, multicenter, observational study conducted in 10 Swiss implanting centers. Patients with a Class I indication according to international guidelines were included and received an ICD with SST. ICD discrimination capability was assessed by evaluating SST performance; therapy efficacy was assessed by rate of VTA conversions by ATP and by rescue shocks.

Results

Overall, 196 patients were included in the analysis with a mean duration of follow-up of 27.7 months (452 patient-years of observation). Patient-specific rather than recommended programming was preferred. Device-detected episodes were frequent (5147 episodes in 146 patients, 74.5%). In 44 patients (22.4%), 1274 episodes were categorized as VTA; only 215 episodes were symptomatic. ATP was the first-line therapy and highly effective (99.9% success rate at the episode level, 100.0% at the patient level). Rescue shocks were rare (66 episodes in 28 patients); 7 shocks in 5 patients (2.6%) were inappropriate. Death and hospitalization rates were low.

Conclusions

In a cohort of non-trial, unselected ICD patients, VTA episodes were frequent. The 4P results confirm the robustness of VTA detection by SST and the effectiveness of ATP treatment, hence limiting overall ICD shock burden.

Korean Guidelines for Diagnosis and Management of Chronic Heart Failure

The prevalence of heart failure (HF) is skyrocketing worldwide, and is closely associated with serious morbidity and mortality. In particular, HF is one of the main causes for the hospitalization and mortality in elderly individuals. Korea also has these epidemiological problems, and HF is responsible for huge socioeconomic burden. However, there has been no clinical guideline for HF management in Korea. 
The present guideline provides the first set of practical guidelines for the management of HF in Korea and was developed using the guideline adaptation process while including as many data from Korean studies as possible. The scope of the present guideline includes the definition, diagnosis, and treatment of chronic HF with reduced/preserved ejection fraction of various etiologies.

End-of-Life Care in the Treatment of Heart Failure in Older Adults

Heart failure presents unique challenges to the clinician who desires to provide excellent and humane care near the end of life. Accurate prediction of mortality in the individual patient is complicated by a chronic disease that is punctuated by recurrent acute episodes and sudden death. Health care providers continue to have difficulty communicating effectively with terminally ill patients and their caregivers regarding end-of-life care preferences, all of which needs to occur earlier rather than later. This article also discusses various means of providing palliative care, and specific issues regarding device therapy, cardiopulmonary resuscitation, and palliative sedation with concurrent discussion of the ethical ramifications and pitfalls of each.

A novel algorithm for ventricular arrhythmia classification using a fuzzy logic approach

In the present study, it has been shown that an unnecessary implantable cardioverter-defibrillator (ICD) shock is often delivered to patients with an ambiguous ECG rhythm in the overlap zone between ventricular tachycardia (VT) and ventricular fibrillation (VF); these shocks significantly increase mortality. Therefore, accurate classification of the arrhythmia into VT, organized VF (OVF) or disorganized VF (DVF) is crucial to assist ICDs to deliver appropriate therapy. A classification algorithm using a fuzzy logic classifier was developed for accurately classifying the arrhythmias into VT, OVF or DVF. Compared with other studies, our method aims to combine ten ECG detectors that are calculated in the time domain and the frequency domain in addition to different levels of complexity for detecting subtle structure differences between VT, OVF and DVF. The classification in the overlap zone between VT and VF is refined by this study to avoid ambiguous identification. The present method was trained and tested using public ECG signal databases. A two-level classification was performed to first detect VT with an accuracy of 92.6 %, and then the discrimination between OVF and DVF was detected with an accuracy of 84.5 %. The validation results indicate that the proposed method has superior performance in identifying the organization level between the three types of arrhythmias (VT, OVF and DVF) and is promising for improving the appropriate therapy choice and decreasing the possibility of sudden cardiac death.

ED evaluation and management of implantable cardiac defibrillator electrical shocks

Patients with implantable cardiac defibrillators not infrequently present to the emergency department after experiencing an implantable cardiac defibrillator shock. This review considers the management of such patients in the emergency department, including appropriate, inappropriate, and phantom shocks as well as electrical storm.

Therapy for ventricular arrhythmias in structural heart disease: a multifaceted challenge

The unpredictable nature and potentially catastrophic consequences of ventricular arrhythmias (VAs) have obligated physicians to search for therapies to prevent sudden cardiac death (SCD). At present, a low left ventricular ejection fraction (LVEF) has been used as a risk factor to predict SCD in patients with structural heart disease and has been consistently adopted as the predominant, and sometimes sole, indication for implantable cardioverter defibrillator (ICD) therapy. Although the ICD remains the mainstay life-saving therapy for SCD, it does not modify the underlying arrhythmic substrate and may be associated with adverse effects from perioperative and long-term complications. Preventative pharmacological therapy has been associated with limited benefits, but anti-arrhythmic medications have significant side effects profiles. Catheter ablation of VAs has greatly evolved over the last few decades. Substrate mapping in sinus rhythm has allowed haemodynamically unstable VAs to be successfully treated. Both LVEF as an indication for ICD therapy and electro-anatomical mapping for substrate modification identify static components of underlying myocardial arrhythmogenicity. They do not take into account dynamic factors, such as the mechanisms of arrhythmia initiation and development of new anatomical or functional lines of block, leading to the initiation and maintenance of VAs. Dynamic factors are difficult to evaluate and consequently are not routinely used in clinical practice to guide treatment. However, progress in the treatment of VAs should consider and integrate dynamic factors with static components to fully characterize the myocardial arrhythmic substrate.

Distribution of Ventricular Fibrosis Associated With Life-Threatening Ventricular Tachyarrhythmias in Patients With Nonischemic Dilated Cardiomyopathy

BACKGROUND

Current guidelines recommend the implantation of an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death (SCD) in a subgroup of patients with nonischemic cardiomyopathy (NICM) who have a left ventricular ejection fraction (LVEF) ≤ 30-35%, and are NYHA functional class II or III. However, the majority of patients with an ICD implantation for primary prevention did not receive appropriate ICD therapy. The purpose of this study was to evaluate the association between myocardial fibrosis detected by cardiovascular magnetic resonance (CMR) imaging and life-threatening ventricular arrhythmic events in NICM patients.

METHODS

One hundred and seventy-five NICM patients with an LVEF ≦ 35 % and NYHA functional class II or III, (60 ± 15 years, LVEF 29 ± 5.4%) were studied. Myocardial fibrosis was identified with a late gadolinium enhancement (LGE) on CMR. Clinical events were defined as SCD or life-threatening ventricular arrhythmic events and were followed up for 5.1 ± 3.3 years.

RESULTS

The presence of an LGE was detected in 122 patients (70%). No life-threatening ventricular arrhythmia events occurred in patients with the absence of an LGE. A total of 18 ventricular tachycardia and 8 ventricular fibrillation events were found in patients with the presence of an LGE (P < 0.01). Sensitivity, specificity, and positive and negative predictive value of LGE in predicting life-threatening ventricular arrhythmia events were 100%, 34%, and 15% and 100%, respectively. Multivariate analysis showed that the presence of both septal and lateral mid-wall LGE was associated with life-threatening ventricular arrhythmic events (hazard ratio 23.1 CI; 2.88-184.9, P = 0.003).

CONCLUSIONS

The absence of an LGE predicts a low potential risk of SCD and life-threatening ventricular arrhythmia events in the near future. CMR may be a useful tool for selecting suitable patients for primary ICD implantations in NICM patients.

Japan Implantable Devices in Coronary Artery Disease (JID-CAD) study design

BACKGROUND

There is little information regarding appropriate therapies for coronary artery disease (CAD) patients with implantable devices - such as implantable cardioverter-defibrillators (ICDs), cardiac resynchronization therapy devices (CRT-Ds) and cardiac resynchronization therapy pacemaker (CRT-P) devices - in Japan. To address this lack of information, we have launched the Japan Implantable Devices in Coronary Artery Disease (JID-CAD) study.

METHODS

This study has been designed as a prospective, multicenter, non-randomized and observational investigation. All patients will be followed up every six months over a two-year period. The primary endpoint will be the administration of appropriate device therapy. Secondary endpoints include administration of inappropriate therapy, death, hospitalization, or cardiovascular events.

CONCLUSION

In this report, we discuss the current clinical situation of appropriate therapy, and how it is influenced by catheter ablation and revascularization therapy in patients with CAD.

Psychological effects of implantable cardioverter defibrillator shocks. A review of study methods

Background: The implantable cardioverter defibrillator (ICD) saves lives but clinical experience suggests that it may have detrimental effects on mental health. The ICD shock has been largely blamed as the main offender but empirical evidence is not consistent, perhaps because of methodological differences across studies.

Objective: To appraise methodologies of studies that assessed the psychological effects of ICD shock and explore associations between methods and results.

Data Sources: A comprehensive search of English articles that were published between 1980 and 30 June 2013 was applied to the following electronic databases: PubMed, EMBASE, NHS HTA database, PsycINFO, Sciencedirect and CINAHL.

Review Methods: Only studies testing the effects of ICD shock on psychological and quality of life outcomes were included. Data were extracted according to a PICOS pre-defined sheet including methods and study quality indicators.

Results: Fifty-four observational studies and six randomized controlled trials met the inclusion criteria. Multiple differences in methods that were used to test the psychological effects of ICD shock were found across them. No significant association with results was observed.

Conclusions: Methodological heterogeneity of study methods is too wide and limits any quantitative attempt to account for the mixed findings. Well-built and standardized research is urgently needed.

A systematic review and meta-analysis of the association between implantable cardioverter-defibrillator shocks and long-term mortality

BACKGROUND

It is unknown whether implantable cardioverter-defibrillator (ICD) discharges actively contribute to a worse prognosis independent of the underlying arrhythmia. There is considerable variability in the reported risk of mortality after appropriate and inappropriate ICD shocks. The aim of our systematic review was to provide a reliable effect size of the association between ICD shock and mortality for both types of therapies.

METHODS

On the basis of a systematic literature search, 10 studies were considered eligible for inclusion in the analysis, and data on the hazard ratio (HR) of mortality after ICD shock were extracted from each study.

RESULTS

On pooled analysis, a substantial difference was detected in the risk for subsequent mortality between appropriate and inappropriate shocks. Among patients receiving an appropriate ICD shock, the HR for cardiac death was 2.95 (95% confidence interval [CI], 2.12-4.11; P < 0.001) compared with an HR of 1.71 (95% CI, 1.45-2.02) for those receiving an inappropriate shock. Clinical variables like ejection fraction, New York Heart Association class, and length of follow-up did not affect the HRs in our meta-regression models.

CONCLUSIONS

Our analysis showed a significant association between appropriate and inappropriate ICD shocks and mortality, with a stronger association for appropriate shocks. Previous trials of ICD therapy reduction programming have shown a significant reduction of inappropriate shocks. The management of appropriate shocks is more challenging and may be optimized by the assessment and treatment of the underlying ventricular arrhythmias. The role of therapies aimed at modifying the arrhythmic substrate and the potential impact on ICD shocks and mortality requires further investigation.