Imagenetics for Precision Medicine in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a common heart muscle disorder of nonischemic etiology associated with heart failure development and the risk of malignant ventricular arrhythmias and sudden cardiac death. A tailored approach to risk stratification and prevention of sudden cardiac death is required in genetic DCM given its variable presentation and phenotypic severity. Currently, advances in cardiogenetics have shed light on disease mechanisms, the complex genetic architecture of DCM, polygenic contributors to disease susceptibility and the role of environmental triggers. Parallel advances in imaging have also enhanced disease recognition and the identification of the wide spectrum of phenotypes falling under the DCM umbrella. Genotype-phenotype associations have been also established for specific subtypes of DCM, such as DSP (desmoplakin) or FLNC (filamin-C) cardiomyopathy but overall, they remain elusive and not readily identifiable. Also, despite the accumulated knowledge on disease mechanisms, certain aspects remain still unclear, such as which patients with DCM are at risk for disease progression or remission after treatment. Imagenetics, that is, the combination of imaging and genetics, is expected to further advance research in the field and contribute to precision medicine in DCM management and treatment. In the present article, we review the existing literature in the field, summarize the established knowledge and emerging data on the value of genetics and imaging in establishing genotype-phenotype associations in DCM and in clinical decision making for DCM patients.

Management of Patients With Unexplained Syncope: Derivation and Validation of a Simplified 2-Step Diagnostic Approach

BACKGROUND

The aim of this study was to develop a structured 2-step approach, based on noninvasive diagnostic criteria, that led to an electrophysiology study in patients with unexplained syncope.

METHODS AND RESULTS

Two independent cohorts were used: the derivation cohort with 665 patients based on electronic health record data to develop our 2-step diagnostic approach, and the validation cohort based on 160 prospectively screened patients, presenting with unexplained syncope episodes. Noninvasive electrocardiographic and imaging markers and an electrophysiology study-based invasive assessment were combined. A positive diagnostic approach according to our study's prespecified criteria resulted in a decision to proceed with a permanent pacemaker/implantable cardioverter-defibrillator. The primary end point was the time until the event of recurrent syncope (syncope-free survival). Number needed to treat was calculated for patients with a positive diagnostic approach. The number of patients with unexplained syncope and borderline sinus bradycardia needed to treat was 5, and the number of patients with unexplained syncope and bundle branch block needed to treat was 3 over a mean follow-up of ≈4 years. After the structured 2-step approach, the primary outcome occurred in 14 of 82 (17.1%) with a pacemaker/implantable cardioverter-defibrillator and 19 of 57 (33%) with a negative approach, with a mean follow-up of ≈2.5 years (29.29±12.58 months, P=0.03).

CONCLUSIONS

The low number needed to treat in the derivation cohort and the low percentage of syncope recurrence in the validation cohort supports the proposed 2-step electrophysiology-inclusive algorithm as a potentially low-cost, 1-day, structured tool for these patients.

The burden of atrial fibrillation and heart failure in hospitalized patients: A real-world survey in a nationwide snapshot

PURPOSE

Atrial fibrillation (AF) and heart failure (HF) are common and commonly coexisting cardiovascular diseases in hospitalized patients. We report the absolute number and interrelation between AF and HF, assess the daily burden of both diseases on the healthcare system, and describe the medical treatment in a real-world, nationwide conducted snapshot survey.

METHODS

A questionnaire was equally distributed to various healthcare institutions. Data on the baseline characteristics, prior hospitalizations, and medical treatments of all hospitalized patients with AF and HF at a predefined date were collected and analyzed.

RESULTS

Seventy-five cardiological departments participated in this multicenter Greek nationwide study. A total of 603 patients (mean age, 74.5 ± 11.4 years) with AF, HF, or the combination of both were nationwide admitted. AF, HF, and the combination of both were registered in 122 (20.2%), 196 (32.5%), and 285 (47.3%) patients, respectively. First-time hospital admission was recorded in 273 (45.7%) of 597 patients, whereas 324 (54.3%) of 597 patients had readmissions in the past 12 months. Of the entire population, 453 (75.1%) were on beta-blockers (BBs), and 430 (71.3%) were on loop diuretics. Furthermore, 315 patients with AF (77.4%) were on oral anticoagulation, of whom 191 (46.9%) were on a direct oral anticoagulant and 124 (30.5%) were on a vitamin K antagonist.

CONCLUSION

Hospitalized patients with AF and/or HF have more than one admission within a year. Coexistence of AF and HF is more common. BBs and loop diuretics are the most commonly used drugs. More than three-quarters of the patients with AF were on oral anticoagulation.

Consensus on the assessment of systemic sclerosis-associated primary heart involvement: World Scleroderma Foundation/Heart Failure Association guidance on screening, diagnosis, and follow-up assessment

Introduction

Heart involvement is a common problem in systemic sclerosis. Recently, a definition of systemic sclerosis primary heart involvement had been proposed. Our aim was to establish consensus guidance on the screening, diagnosis and follow-up of systemic sclerosis primary heart involvement patients.

Methods

A systematic literature review was performed to investigate the tests used to evaluate heart involvement in systemic sclerosis. The extracted data were categorized into relevant domains (conventional radiology, electrocardiography, echocardiography, cardiac magnetic resonance imaging, laboratory, and others) and presented to experts and one patient research partner, who discussed the data and added their opinion. This led to the formulation of overarching principles and guidance statements, then reviewed and voted on for agreement. Consensus was attained when the mean agreement was ⩾7/10 and of ⩾70% of voters.

Results

Among 2650 publications, 168 met eligibility criteria; the data extracted were discussed over three meetings. Seven overarching principles and 10 guidance points were created, revised and voted on. The consensus highlighted the importance of patient counseling, differential diagnosis and multidisciplinary team management, as well as defining screening and diagnostic approaches. The initial core evaluation should integrate history, physical examination, rest electrocardiography, trans-thoracic echocardiography and standard serum cardiac biomarkers. Further investigations should be individually tailored and decided through a multidisciplinary management. The overall mean agreement was 9.1/10, with mean 93% of experts voting above 7/10.

Conclusion

This consensus-based guidance on screening, diagnosis and follow-up of systemic sclerosis primary heart involvement provides a foundation for standard of care and future feasibility studies that are ongoing to support its application in clinical practice.

Management of Patients With Unexplained Syncope and Bundle Branch Block: Predictive Factors of Recurrent Syncope

Syncope in patients with bundle branch block (BBB) is often due to advanced atrioventricular (AV) block. The objective of the present "real-world" study was to evaluate the optimal management in patients with unexplained syncope and BBB and to identify factors that predict the recurrence of syncope. This is a single-center observational prospective registry of 131 consecutive patients undergoing invasive electrophysiology study (EPS) for recurrent unexplained presyncope or syncope attacks and BBB. When the EPS-derived diagnosis was reached, a decision to proceed with a permanent pacemaker was offered to the patient. An implantable loop recorder was inserted in the rest of the population. A total of 131 consecutive patients with unexplained syncope and BBB (67.2% male; age 63.7 ± 16.5 years) underwent EPS during the study period. The distribution of conduction disturbance patterns was as follows: isolated left bundle branch block (LBBB): 23.7%; LBBB with first AV block: 8.4%; isolated right bundle branch block (RBBB): 10.7%; RBBB with first AV block: 8.4%; isolated left anterior/posterior fascicular block: 13%; left anterior/posterior fascicular block with first AV block: 5.3%; isolated bifascicular block: 16.8%; and bifascicular block with first AV block: 13.7%. In the multivariate analysis, the only predictors of recurrent syncope were bifascicular block (hazard ratio (HR): 4.16, 95% confidence interval (CI): 1.29, 13.41, P: 0.017) and HV interval ≥ 60 msec (HR: 3.58, 95% CI: 1.12, 11.46, P: 0.032). An EPS-based strategy identifies a subset of patients who will benefit from permanent pacing. HV interval ≥ 60 msec and the presence of a bifascicular block were strongly related to syncope recurrence.

Noninvasive electrocardiographic risk factors for sudden cardiac death in dilated ca rdiomyopathy: is ambulatory electrocardiography still relevant?

Risk stratification for sudden cardiac death in dilated cardiomyopathy is a field of constant debate, and the currently proposed criteria have been widely questioned due to their low positive and negative predictive value. In this study, we conducted a systematic review of the literature utilizing the PubMed and Cochrane library platforms, in order to gain insight about dilated cardiomyopathy and its arrhythmic risk stratification utilizing noninvasive risk markers derived mainly from 24 h electrocardiographic monitoring. The obtained articles were reviewed in order to register the various electrocardiographic noninvasive risk factors used, their prevalence, and their prognostic significance in dilated cardiomyopathy. Premature ventricular complexes, nonsustained ventricular tachycardia, late potentials on Signal averaged electrocardiography, T wave alternans, heart rate variability and deceleration capacity of the heart rate, all have both some positive and negative predictive value to identify patients in higher likelihood for ventricular arrhythmias and sudden cardiac death. Corrected QT, QT dispersion, and turbulence slope-turbulence onset of heart rate have yet to establish a predictive correlation in the literature. Although ambulatory electrocardiographic monitoring is frequently used in clinical practice in DCM patients, no single risk marker can be used for the selection of patients at high-risk for malignant ventricular arrhythmic events and sudden cardiac death who could benefit from the implantation of a defibrillator. More studies are needed in order to establish a risk score or a combination of risk factors with the purpose of selecting high-risk patients for ICD implantation in the context of primary prevention.

Prediction of programmed ventricular stimulation inducibility using machine learning in post-myocardial infarction patients at risk for sudden cardiac arrest with preserved ejection fraction ≥40%

Introduction

Sudden cardiac death (SCD) in post myocardial infarction (post-MI) patients with a relatively preserved left ventricular ejection fraction (LVEF ≥40%) has 1% annual incidence. In the PRESERVE-EF study, we used a two-step SCD risk stratification approach to detect patients with a relatively preserved left ventricular ejection fraction ≥40% at risk for major arrhythmic events. Seven noninvasive risk factors (NIRFs) were extracted from ambulatory electrocardiography. Patients with at least one NIRF present were referred for invasive programmed ventricular stimulation (PVS). Inducible patients received an ICD.

Purpose

The present study examines the performance of machine learning technology for the prediction of the inducible patients in PRESERVE-EF study.

Methods

After first step screening with NIRFs, 152 out of 575 patients underwent PVS and 41 of them were inducible. For the present analysis, data from these 152 patients were analysed. We used machine learning of NIRFs to predict these inducible high risk patients. We selected as classification method the Nearest Neighbour (NN) algorithm, after experimentation with several classifiers. NN classifies each subject according to the class of the N nearest neighbours. For each subject, we created a vector with the following 7 features: SAECG Late Potentials, Ventricular Premature beats ≥30/hour, Non-sustained Ventricular Tachycardia ≥1 episode (s)/24 hours, Fredericia corrected QT interval ≥45 0ms, SDNN/HRV ≤75 ms, T Wave Alternans ≥65 μV, Combined Deceleration capacity (DC) ≤4.5 ms and Heart Rate Turbulence Onset (To) ≥0% and Heart Rate Turbulence Slope (Ts) ≤2.5 ms.

Results

The achieved accuracy reached up to 72.2% when N was set to 7. We had totally 144 samples, 41 of which were inducible high risk patients. Results were similar for other values of N. To ensure independence of train and test sets, we employed 10-fold cross validation.

Conclusions

Inducible on PVS patients in PRESERVE-EF study were predicted with machine learning classification of NIRFs.

Funding Acknowledgement

Type of funding sources: None.

Atrial high-rate episodes in patients with devices without a history of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Atrial high-rate episodes (AHREs) recorded with cardiac implantable electronic devices (CIEDs) have been associated with the development of clinical atrial fibrillation (AF) and increase in stroke, and death risk.

Purpose

We sought to perform a systematic review with a meta-analysis to evaluate the prevalence of AHREs detected by CIEDs, their association with stroke risk, development of clinical AF, and mortality among patients without a documented history of AF.

Methods

We searched several databases, ClinicalTrials.gov, references of reviews, and meeting abstract books without any language restrictions up to 9 September 2020. We studied patients with CIEDs in whom AHREs were detected. Exclusion criteria were an AF history. Our primary outcome was the risk of ischemic stroke in patients with AHREs.

Results

We deemed eligible eight studies for the meta-analysis enrolling a total of 4322 patients with CIED and without a documented AF history. Evidence of moderate certainty suggests that patients with documented AHREs were 4.45 times (95% CI 2.87–6.91) more likely to develop clinical AF. Evidence of low confidence suggests that AHREs were associated with a 1.90-fold increased stroke risk (95% CI 1.19–3.05).

Conclusion

The present systematic review and meta-analysis demonstrated that among patients without a documented history of AF, the detection of AHREs by CIEDs was associated with significant increased risk of clinical AF and stroke.

Remote Cardiac Rhythm Monitoring in the Era of Smart Wearables: Present Assets and Future Perspectives

Remote monitoring and control of heart function are of primary importance for patient evaluation and management, especially in the modern era of precision medicine and personalized approach. Breaking technological developments have brought to the frontline a variety of smart wearable devices, such as smartwatches, chest patches/straps, or sensors integrated into clothing and footwear, which allow continuous and real-time recording of heart rate, facilitating the detection of cardiac arrhythmias. However, there is great diversity and significant differences in the type and quality of the information they provide, thus impairing their integration into daily clinical practice and the relevant familiarization of practicing physicians. This review will summarize the different types and dominant functions of cardiac smart wearables available in the market. Furthermore, we report the devices certified by official American and/or European authorities and the respective sources of evidence. Finally, we comment pertinent limitations and caveats as well as the potential answers that flow from the latest technological achievements and future perspectives.

Cavotricuspid isthmus ablation guided by force-time integral - A randomized study

Background

Force‐time integral (FTI) is an ablation marker of lesion quality and transmurality. A target FTI of 400 gram‐seconds (gs) has been shown to improve durability of pulmonary vein isolation, following atrial fibrillation ablation. However, relevant targets for cavotricuspid isthmus (CTI) ablation are lacking.

Hypothesis

We sought to investigate whether CTI ablation with 600 gs FTI lesions is associated with reduced rate of transisthmus conduction recovery compared to 400 gs lesions.

Methods

Fifty patients with CTI‐dependent flutter were randomized to ablation using 400 gs (FTI400 group, n = 26) or 600 gs FTI lesions (FTI600 group, n = 24). The study endpoint was spontaneous or adenosine‐mediated recovery of transisthmus conduction, after a 20‐min waiting period.

Results

The study endpoint occurred in five patients (19.2%) in group FTI400 and in four patients (16.7%) in group FTI600, p = .81. First‐pass CTI block was similar in both groups (50% in FTI400 vs. 54.2% in FTI600, p = .77). There were no differences in the total number of lesions, total ablation time, procedure time and fluoroscopy duration between the two groups. There were no major complications in any group. In the total population, patients not achieving first‐pass CTI block had significantly higher rate of acute CTI conduction recovery, compared to those with first‐pass block (29.2% vs. 7.7% respectively, p = .048).

Conclusions

CTI ablation using 600 gs FTI lesions is not associated with reduced spontaneous or adenosine‐mediated recurrence of transisthmus conduction, compared to 400 gs lesions.

Primary systemic sclerosis heart involvement: A systematic literature review and preliminary data-driven, consensus-based WSF/HFA definition

Introduction

Primary heart involvement in systemic sclerosis may cause morpho-functional and electrical cardiac abnormalities and is a common cause of death. The absence of a clear definition of primary heart involvement in systemic sclerosis limits our understanding and ability to focus on clinical research. We aimed to create an expert consensus definition for primary heart involvement in systemic sclerosis.

Methods

A systematic literature review of cardiac involvement and manifestations in systemic sclerosis was conducted to inform an international and multi-disciplinary task force. In addition, the nominal group technique was used to derive a definition that was then subject to voting. A total of 16 clinical cases were evaluated to test face validity, feasibility, reliability and criterion validity of the newly created definition.

Results

In total, 171 publications met eligibility criteria. Using the nominal group technique, experts added their opinion, provided statements to consider and ranked them to create the consensus definition, which received 100% agreement on face validity. A median 60(5-300) seconds was taken for the feasibility on a single case. Inter-rater agreement was moderate (mKappa (95% CI) = 0.56 (0.46-1.00) for the first round and 0.55 (0.44-1.00) for the second round) and intra-rater agreement was good (mKappa (95% CI) = 0.77 (0.47-1.00)). Criterion validity showed a 78 (73-84)% correctness versus gold standard.

Conclusion

A preliminary primary heart involvement in systemic sclerosis consensus-based definition was created and partially validated, for use in future clinical research.

Atrial fibrosis as a dominant factor for the development of atrial fibrillation: facts and gaps

Atrial fibrillation (AF), the most commonly diagnosed arrhythmia, affects a notable percentage of the population and constitutes a major risk factor for thromboembolic events and other heart-related conditions. Fibrosis plays an important role in the onset and perpetuation of AF through structural and electrical remodelling processes. Multiple molecular pathways are involved in atrial substrate modification and the subsequent maintenance of AF. In this review, we aim to recapitulate underlying molecular pathways leading to atrial fibrosis and to indicate existing gaps in the complex interplay of atrial fibrosis and AF.