Implantable cardiac defibrillators for people with non-ischaemic cardiomyopathy

When amiodarone-induced thyroiditis meets cardiomyopathy with excessive trabeculation: a case report

Introduction

Amiodarone is a potent antiarrhythmic medication used to treat life-threatening ventricular arrhythmias; however, its well-established adverse effect is a thyroid disorder. Amiodarone-induced thyroiditis (AIT), a clinical entity involving two types with different etiopathology and treatment approaches, may occur at the beginning or even several years after amiodarone treatment discontinuation. The toxicity profile of amiodarone becomes especially important in young patients with lifelong cardiac disorders, which are often refractory to other antiarrhythmic drugs. Herein, we report the first case of non-sustained ventricular tachycardia (NSVT), an unusual presentation of type II AIT, in a young male patient who was previously diagnosed with left ventricular cardiomyopathy with excessive trabeculation.

Case report

A 36-year-old male non-athlete presented with tiredness during regular follow-up. Continuous electrocardiographic monitoring (cECG) revealed NSVT, whereas echocardiography and cardiac magnetic resonance imaging detected discrete structural and functional changes that could not fully explain the observed cECG report. Conversely, an unmeasurably low thyrotropin level on admission and previous exposure to amiodarone pointed the diagnostic pathway in the direction of the thyroid gland. Elevated free thyroxine and undetectable autoantibody titers with unremarkable sonographic findings raised clinical suspicion of type II AIT. Scintigraphic imaging with 99mTc-2-methoxyisobutylisonitrile (sestamibi) revealed decreased thyroid uptake; hence, prednisone was introduced for treatment. Clear improvements in both biochemical and electrocardiographic parameters were observed after immunomodulatory treatment of type II AIT in this young patient with cardiomyopathy and excessive trabeculation.

Conclusion

Treatment of reversible causes of cardiac rhythm abnormalities such as type II AIT should be considered before choosing other treatment modalities, particularly in patients with structural cardiac disorders. The importance of a multidisciplinary approach in complex cases such as the one reported, thus, cannot be emphasized enough.

An updated meta-analysis of cardiac resynchronization therapy with or without defibrillation in patients with nonischemic cardiomyopathy

Background

Cardiac resynchronization therapy (CRT) is a major device therapy used to treat patients suffering from heart failure (HF) and electrical asynchrony. It can improve HF symptoms, reduce HF hospitalization time, and improve long-term survival in HF with and without implantable cardioverter (ICD) therapy. However, the benefit of defibrillator therapy in CRT-eligible patients with nonischemic cardiomyopathy (NICM) remains unknown. As a result, we conducted a systematic review and meta-analysis to compare clinical outcomes in patients with NICM and HF who were treated with implantable CRT defibrillators (CRT-D) vs. a CRT pacemaker (CRT-P) alone.

Methods

We searched the electronic databases PubMed, Embase, and Cochrane for all studies comparing CRT-D vs. CRT-P treatment in patients with NICM. The time frame was from 1990 to September 2022. All-cause mortality and cardiovascular mortality were the primary clinical outcomes of interest to us. To pool adjusted hazard ratios (HRs) and 95% confidence intervals (CIs), a random-effects model with inverse variance was used.

Results

A pooled meta-analysis included two randomized controlled trials (RCTs), each with 1,200 CRT-eligible patients with NICM (592 with CRT-D and 608 with CRT-P) and nine cohort studies representing 27,568 CRT-eligible patients with NICM (16,196 with CRT-D and 11,372 with CRT-P). The adjusted HR for all-cause mortality for CRT-D vs. CRT-P was 0.90 (95% CI, 0.81-0.99). In a subgroup analysis of two RCTs and nine cohort studies, the adjusted HR for all-cause mortality was 0.72 (95% CI, 0.43-1.19) and HR 0.92 (95% CI, 0.83-1.03) for CRT-D vs. CRT-P, respectively.

Conclusion

With the addition of defibrillation leads, we found a significantly lower risk of all-cause mortality in patients with NICM, but this association was not found in subgroup analyses of RCTs and observational studies.

An implantable cardioverter-defibrillator for primary prevention in non-ischemic cardiomyopathy: A systematic review and meta-analysis

BACKGROUND

Recent data regarding the comparison of implantable cardioverter-defibrillator (ICD) therapy and optimal medical treatment in patients with non-ischemic cardiomyopathy has indicated no mortality benefit as a result of ICD therapy. Although the recommendations for ICD implantation did not change, it is worth noting that these findings significantly affected the daily practice of ICD implantation in Europe.

METHODS

To assess the effect of ICD implantation in comparison to pharmacotherapy in the non- -ischemic cardiomyopathy heart failure population through a systematic review and meta-analysis of the available carefully designed prospective randomized controlled trials. Only prospective randomized controlled trials comparing ICD implantation in primary prevention vs. optimal pharmacological therapy or placebo and reporting mortality results were included in the meta-analysis. The authors have chosen to include the following trials: CAT, AMIOVIRT, DEFINITE, and DANISH.

RESULTS

A meta-analysis of pooled hazard ratios (HR) from all trials conducted on a total of 1789 patients found that ICD therapy decreased all-cause mortality in comparison to optimal pharmacological treatment, with a HR of 0.48 (95% confidence interval [CI] 0.67-1.01); p = 0.06. The data from the AMIOVIRT, DANISH, and DEFINITE trials, with a total of 1677 participants, showed a significant reduction of sudden cardiac deaths as a result of ICD implantation, with a HR of 0.48 (95% CI 0.31-0.67); p < 0.001.

CONCLUSIONS

In comparison with optimal medical treatment, ICD implantation in patients with heart failure improves the long-term prognosis in terms of sudden cardiac death, with a strong tendency towards all-cause mortality reduction.

Health-related quality of life in patients with implantable cardioverter defibrillators in Sweden: a cross-sectional observational trial

OBJECTIVES

Decisions regarding implantable cardioverter defibrillators (ICDs) must consider information about presumed health-related quality of life (HRQL). The purpose of the study was to assess HRQL in patients with ICD and compare it to a Swedish age-matched and sex-matched population.

DESIGN

Cross-sectional observational trial.

SETTING

Swedish ICD cohort.

INTERVENTIONS

Short form 36 (SF-36) questionnaires from ICD recipients implanted 2007-2017 (response rate 77.2%) were analysed using Mann-Whitney U test and effect size (ES).

RESULTS

In total, 223 patients (mean age 71.1±9.7 years, 82.1% men) were included. In most SF-36 domains (physical functioning (PF), role physical, general health (GH), vitality, social functioning and mental health), the score for patients with ICD was significantly lower (ES range 0.23-0.41, ie, small difference) than norms, except for bodily pain and role emotional. Both the physical component summary (PCS) and the mental component summary (MCS) scores had ES=0.31. Men and women had similar scores. Primary and secondary prevention patients scored similarly, except for worse GH in primary prevention (p=0.016, ES=0.35). Atrial fibrillation was associated with worse PF (ES=0.41) and PCS (ES=0.38). Appropriate therapy, inappropriate shock or complications requiring surgery were not associated with lower scores in any domain. In primary prevention due to ischaemic versus non-ischaemic cardiomyopathy, no domain was significantly different. PCS decreased with higher age strata (p=0.002) in contrast to MCS (p=0.986).

CONCLUSIONS

Patients with ICDs have lower physical and mental HRQL than age-matched and sex-matched norms; however, the ESs are small. HRQL is similar regardless of sex, primary/secondary prevention indication, appropriate therapy, inappropriate shock or complications, but decreases with advancing age.

The prognostic role of late gadolinium enhancement on cardiac magnetic resonance in patients with nonischemic cardiomyopathy and reduced ejection fraction, implanted with cardioverter defibrillators for primary prevention. A systematic review and meta-analysis

BACKGROUND

Previous studies suggest that late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is associated with arrhythmic events in patients with nonischemic cardiomyopathy (NICM), while others have questioned the role of left ventricular ejection fraction (LVEF) as a sole predictor of future events.

OBJECTIVES

To evaluate the role of LGE on CMR in identifying patients with NICM and reduced LVEF for whom a benefit from defibrillator implantation for primary prevention is not anticipated, thus they are mainly exposed to potential risks.

METHODS

Major electronic databases were searched for studies reporting the incidence of appropriate device therapy (ADT), sudden cardiac death (SCD), and cardiac death based on the presence of LGE on CMR, among patients with NICM and reduced LVEF, implanted with a cardioverter defibrillator for primary prevention.

RESULTS

Eleven studies (1652 patients, 947 with LGE) were included in the final analysis. LGE presence was strongly associated with ADT (logOR: 1.95, 95%CI: 1.21-2.69) and cardiac death (logOR: 0.91, 95%CI: 0.14-1.68), but not with SCD (logOR: 0.26, 95%CI: -1.09-1.6). Diagnostic accuracy analysis demonstrated that contrast enhancement is a sensitive marker of future ADT and cardiac death (93%, 95%CI: 85.8-96.7%; 82.9%, 95%CI: 70.6-90.7%; respectively), with moderate specificity ( 44%, 95%CI: 27.2-62.6%; 37.7%, 95%CI: 23.4-54.6%; respectively).

CONCLUSION

LGE is a highly sensitive predictor of ADT and cardiac death in NICM patients implanted with a defibrillator for primary prevention. However, due to moderate specificity, derivation of a cutoff with adequate predictive values and probably a multifactorial approach are needed to improve discrimination of patients who will not benefit from ICDs.

Clinical Outcomes of Implantable Cardioverter-Defibrillator in Pediatric Patients - A Korean Multicenter Study

BACKGROUND

Implantable cardioverter-defibrillator (ICD) therapy is important for the prevention of sudden cardiac death, but data on clinical outcomes of ICD therapy in Asian pediatric patients are scarce. The aim of this Korean multicenter study was to evaluate the current state and elucidate the clinical outcomes of ICD therapy in children.Methods and Results:Data from 5 pediatric cardiology centers were retrospectively collected from 2007 to 2019. Altogether, 99 patients were enrolled (mean age 13.9±4.1 years). The most common underlying disease was a primary electrical disease (56%). An ICD was implanted for primary prevention in 19%. Appropriate shock occurred in 44% of patients at a median of 1.6 years after implantation. There was no significant difference in the appropriate shock rate between patients with primary and secondary prevention indications (32% vs. 48%, respectively). A total of 33 patients (33%) experienced inappropriate shock, which was associated with primary electrical disease and follow-up duration on multivariate analysis. 17% of patients had ICD-related complications.

CONCLUSIONS

The utilization rate of ICD for primary prevention was still low in the pediatric population in Korea, but there was a substantial rate of appropriate shock in these patients. Efforts to increase ICD usage to save the lives of high-risk patients and reduce the incidence of inappropriate shock are required.

Exploring the acceptability of implantable defibrillators in patients with cardiac dystrophinopathy and carers

Objective

Unlike for patients with other forms of cardiomyopathies, those with severe ventricular dysfunction due to Duchenne muscular dystrophy (DMD) are not offered implantable cardioverter-defibrillator (ICD) therapy routinely. This prospective study aimed to determine the views of DMD-patients and their carers about discussing sudden death risk and their acceptance of ICDs.

Design and setting

Adults with DMD (n=9) and parents/carers (n=9) participated in audio-recorded, 60–90 min focus group sessions (patients 2; parents/carers 2) conducted through either a face-to-face session at a neutral venue or a videoconference. Sessions were facilitated by a clinical psychologist, experienced in conducting focus group research. All participants understood the rationale for the study and the nature of ICD therapy. The same predefined themes were explored with each group. Recordings were transcribed, analysed thematically by two researchers, working independently and then agreed. Differences in responses between patient and carer groups were also studied and compared. Participants all provided informed written consent and the study had ethical approval.

Results

Three main themes emerged: (1) access to/quality of information provided by professionals and patient engagement with them; (2) decision-making about ICDs; (3) individuals’ own ‘lived experience’ of DMD.

Conclusions

The main findings were: (1) patients with DMD want to have their risk of sudden arrhythmic death discussed, when relevant and (2) if ICD therapy were established as beneficial, they would welcome an individualised discussion about its appropriateness for them.