Systematic review for the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society

Cardiac care of children with dystrophinopathy and females carrying DMD-gene variations

OBJECTIVE

We provide succinct, evidence-based and/or consensus-based best practice guidance for the cardiac care of children living with Duchenne muscular dystrophy (DMD) as well as recommendations for screening and management of female carriers of mutations in the DMD-gene.

METHODS

Initiated by an expert working group of UK-based cardiologists, neuromuscular clinicians and DMD-patient representatives, draft guidelines were created based on published evidence, current practice and expert opinion. After wider consultation with UK-cardiologists, consensus was reached on these best-practice recommendations for cardiac care in DMD.

RESULTS

The resulting recommendations are presented in the form of a succinct care pathway flow chart with brief justification. The guidance signposts evidence on which they are based and acknowledges where there have been differences in opinion. Guidelines for cardiac care of patients with more advanced cardiac dystrophinopathy at any age have also been considered, based on the previous published work of Quinlivan et al and are presented here in a similar format. The recommendations have been endorsed by the British Cardiovascular Society.

CONCLUSION

These guidelines provide succinct, reasoned recommendations for all those managing paediatric patients with early or advanced stages of cardiomyopathy as well as females with cardiac dystrophinopathy. The hope is that this will result in more uniform delivery of high standards of care for children with cardiac dystrophinopathy, so improving heart health into adulthood through timely earlier interventions across the UK.

Computational Analysis of Mapping Catheter Geometry and Contact Quality Effects on Rotor Detection in Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia and catheter mapping has been proved to be an effective approach for detecting AF drivers to be targeted by ablation. Among drivers, the so-called rotors have gained the most attention: their identification and spatial location could help to understand which patient-specific mechanisms are acting, and thus to guide the ablation execution. Since rotor detection by multi-electrode catheters may be influenced by several structural parameters including inter-electrode spacing, catheter coverage, and endocardium-catheter distance, in this study we proposed a tool for testing the ability of different catheter shapes to detect rotors in different conditions. An approach based on the solution of the monodomain equations coupled with a modified Courtemanche ionic atrial model, that considers an electrical remodeling, was applied to simulate spiral wave dynamics on a 2D model for 7.75 s. The developed framework allowed the acquisition of unipolar signals at 2 KHz. Two high-density multipolar catheters were simulated (Advisor™ HD Grid and PentaRay^®) and placed in a 2D region in which the simulated spiral wave persists longer. The configuration of the catheters was then modified by changing the number of electrodes, inter-electrodes distance, position, and atrial-wall distance for assessing how they would affect the rotor detection. In contact with the wall and at 1 mm distance from it, all the configurations detected the rotor correctly, irrespective of geometry, coverage, and inter-electrode distance. In the HDGrid-like geometry, the increase of the inter-electrode distance from 3 to 6 mm caused rotor detection failure at 2 mm distance from the LA wall. In the PentaRay-like configuration, regardless of inter-electrode distance, rotor detection failed at 3 mm endocardium-catheter distance. The asymmetry of this catheter resulted in rotation-dependent rotor detection. To conclude, the computational framework we developed is based on realistic catheter shapes designed with parameter configurations which resemble clinical settings. Results showed it is well suited to investigate how mapping catheter geometry and location affect AF driver detection, therefore it is a reliable tool to design and test new mapping catheters.

Cardiac MRI Assessment of Mouse Myocardial Infarction and Regeneration

Small animal models are indispensable for cardiac regeneration research. Studies in mouse and rat models have provided important insights into the etiology and mechanisms of cardiovascular diseases and accelerated the development of therapeutic strategies. It is vitally important to be able to evaluate the therapeutic efficacy and have reliable surrogate markers for therapeutic development for cardiac regeneration research. Magnetic resonance imaging (MRI), a versatile and noninvasive imaging modality with excellent penetration depth, tissue coverage, and soft-tissue contrast, is becoming a more important tool in both clinical settings and research arenas. Cardiac MRI (CMR) is versatile, noninvasive, and capable of measuring many different aspects of cardiac functions, and, thus, is ideally suited to evaluate therapeutic efficacy for cardiac regeneration. CMR applications include assessment of cardiac anatomy, regional wall motion, myocardial perfusion, myocardial viability, cardiac function assessment, assessment of myocardial infarction, and myocardial injury. Myocardial infarction models in mice are commonly used model systems for cardiac regeneration research. In this chapter, we discuss various CMR applications to evaluate cardiac functions and inflammation after myocardial infarction.

Prognostic significance of a low T/R ratio in Brugada syndrome

OBJECTIVES

To determine the prognostic value of a low T/R ratio, defined as the amplitude ratio between the T waves and the R waves, in patients (pts) with a spontaneous type-1 Brugada pattern (SBT1).

BACKGROUND

Abnormalities of myocardial repolarization may play a key role in the initiation of ventricular fibrillation (VF) in Brugada syndrome (BrS). Recent studies have shown that the height of the T waves and the T/R ratio are inversely proportional to sudden cardiac arrest (SCA) risk in early repolarization syndrome and hypertrophic cardiomyopathy.

METHODS

In an international retrospective study, we reviewed 115 pts. (105 males, 91.3%). 45 had VF and/or SCA (38.7 ± 11.5 years old, all males), while 70 (49.3 ± 12.0 years, 10 women) remained free of ventricular arrhythmia. 6 ECG markers plus the T/R ratio in leads V5 & II were studied.

RESULTS

The T/R ratio among leads II & V5 was significantly lower in the VF/SCA group (0.24 [0.14; 0.38]vs. 0.34 [0.24; 0.45]; p = 0.006). 44.4% of pts. in the VF/SCA group had a lowest T/R ratio among leads II & V5 ≤ 0.17 compared to 11.4% in the non-VF/SCA group (p < 0.001). In multivariate analysis, a lowest T/R ratio among leads II & V5 ≤ 0.17 was independently associated with VF/SCA (OR 6.10, 95% CI 1.92-19.40; p = 0.002). Type 1 Brugada pattern in the peripheral leads (OR 10.78) and early repolarization (OR 3.60) were other independent markers of VF/SCA.

CONCLUSION

A low T/R ratio among leads II & V5 is an independent marker for VF/SCA risk in patients with type-1 Brugada pattern.

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.

Frailty, Implantable Cardioverter Defibrillators, and Mortality: a Systematic Review

BACKGROUND

Evidence for the benefit of implantable cardioverter defibrillators (ICD) in preventing sudden cardiac death (SCD) in older adults is mixed; age alone may not predict benefit. Frailty may help identify patients in whom an ICD does not improve overall mortality risk.

METHODS

Structured search of PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials on 1/31/2019, without language restriction, with terms for ICD, frailty, and mortality. Frailty was defined broadly using any validated single component (e.g., walking speed, weight loss) or multi-component tool (e.g., cumulative deficit index). Each study was assessed for quality and risk of bias.

RESULTS

We identified and screened 2649 titles, reviewed 280 abstracts, and extracted 71 articles. Nine articles, including two RCTs, one prospective cohort, and six retrospective cohort studies met all criteria. The most common reason for exclusion was a lack of frailty definition. Frailty definitions were heterogeneous, including cumulative deficit models, low weight, and walking speed. Follow-up time for mortality differed: from days to > 6 years. All studies indicated that mortality was higher amongst individuals identified as frail, regardless of definition. In one RCT, slow walkers did not benefit from ICD therapy after 3 years. A cohort of 83,792 Medicare beneficiaries in an ICD registry reported higher 1-year mortality following ICD in those with frailty or dementia. Four studies reported an association between being underweight and increased mortality following ICD placement.

CONCLUSION

Existing literature suggests that individuals with frailty may not benefit from ICD placement for primary prevention of SCD.

Insights for Stratification of Risk in Brugada Syndrome

Brugada syndrome (BrS) is an inherited disease with an increased risk of sudden cardiac death (SCD). However, testing identifies genetic disorders in only 20-30% of patients analysed, indicating a gap in knowledge of its genetic aetiology. Diagnosis relies on ECG, and risk stratification in BrS patients is challenging, primarily because of the complexity of the issue. As a result, clinicians fail to provide the appropriate strategy for SCD prevention for many patients. Several variables and interventions are being studied to improve diagnostics and maximise patient protection. In addition, the scientific community must increase efforts to provide patient care according to knowledge and research for improving stratification of risk. In this article, the authors summarise contemporary evidence on clinical variables and provide an overview of future directions in risk stratification and SCD prevention.

The Role of Palliative Care in the Cardiac Intensive Care Unit

In the last few years, important changes have occurred in the clinical and epidemiological characteristics of patients that were admitted to cardiac intensive care units (CICU). Care has shifted from acute coronary syndrome patients towards elderly patients, with a high prevalence of non-ischemic cardiovascular diseases and a high burden of non-cardiovascular comorbid conditions: both increase the susceptibility of patients to developing life-threatening critical conditions. These conditions are associated with a significant symptom burden and mortality rate and an increased length of stay. In this context, palliative care programs, including withholding/withdrawing life support treatments or the deactivation of implanted cardiac devices, are frequently needed, according to the specific guidelines of scientific societies. However, the implementation of these recommendations in clinical practice is still inconsistent. In this review, we analyze the reasons for this gap and the main cultural changes that are required to improve the care of patients with advanced illness.