Right-ventricular enlargement in arrhythmogenic right-ventricular cardiomyopathy is associated with decreased QRS amplitudes and T-wave negativity

Electrocardiogram in arrhytmogenic cardiomyopathy

Criteria for diagnosis of arrhythmogenic cardiomyopathy (ACM) were first proposed in 1994 and subsequently revised in 2010 and in 2020 by an international task force. According to the last consensus of 2020, ACM is defined as a heart muscle disease affecting right ventricle, left ventricle or both, whose principal pathologic feature is fibrofatty myocardial replacement that impairs systolic ventricular function and predisposes to lethal ventricular arrhythmias. ECG findings not only could help to early recognize affected patients but also could identify the ones with maximum risk of ventricular arrhythmias and sudden cardiac death.

QRS dispersion detected in ARVC patients and healthy gene carriers using 252-leads body surface mapping: an explorative study of a potential diagnostic tool for arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

The diagnosis of ARVC remains complex requiring both imaging and electrocardiographic (ECG) techniques. The purpose was therefore to investigate whether QRS dispersion assessed by body surface mapping (BSM) could be used to detect early signs of ARVC, particularly in gene carriers.

METHODS

ARVC patients, gene carriers without a history of arrhythmias or structural cardiac changes and healthy controls underwent 12-lead resting ECG, signal-averaged ECG, echocardiographic examination, 24-hours Holter monitoring, and BSM with electrocardiographic imaging. All 252-leads BSM recordings and 12-leads ECG recordings were manually analyzed for QRS durations and QRS dispersion.

RESULTS

Eight controls, 12 ARVC patients with definite ARVC and 20 healthy gene carriers were included. The ECG-QRS dispersion was significantly greater in ARVC patients (42 vs. 25 ms, p < .05), but failed to fully differentiate them from controls. The BSM-derived QRS dispersion was also significantly greater in ARVC patients versus controls (65 vs. 29 ms, p < .05) and distinguished 11/12 cases from controls using the cut-off 40msec. The BSM derived QRS dispersion was abnormal (> 40 ms) in 4/20 healthy gene carriers without signs of ARVC, which may indicate early depolarization changes.

CONCLUSIONS

QRS dispersion, when assessed by BSM versus 12-lead ECG, seem to better distinguish ARVC patients from controls, and could potentially be used to detect early ARVC in gene carriers. Further studies are required to confirm the value of BSM-QRS dispersion in this respect.

Diagnostic and prognostic value of low QRS voltages in cardiomyopathies: old but gold

The interpretation of 12-lead resting electrocardiogram (ECG) in patients with a definitive diagnosis or with the suspicion of a cardiomyopathy represents a cornerstone for the diagnostic work up and management of patients. Although low electrocardiographic QRS voltages (LQRSV) detected by 12-lead resting ECG have historically been acknowledged by physicians, in view of recent evidence on the demonstration of myocardial scar by cardiac magnetic resonance and its relevance as a cause of sudden cardiac death even in young individuals, a new interest has been raised about the utility of LQRSV in the clinical practice. Beyond their diagnostic value, LQRSV have also demonstrated a prognostic role in different cardiomyopathies. The present review summarizes the diagnostic and prognostic value of LQRSV in cardiomyopathies, reporting the new evidence, primarily based on advanced imaging studies, supporting the clinical utility of this parameter.

Clinical Diagnosis, Imaging, and Genetics of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: JACC State-of-the-Art Review. J Am Coll Cardiol. 2018;72:784-804. [PMID: 30092956 DOI: 10.1016/j.jacc.2018.05.065]

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited cardiomyopathy that can lead to sudden cardiac death and heart failure. Our understanding of its pathophysiology and clinical expressivity is continuously evolving. The diagnosis of ARVC/D remains particularly challenging due to the absence of specific unique diagnostic criteria, its variable expressivity, and incomplete penetrance. Advances in genetics have enlarged the clinical spectrum of the disease, highlighting possible phenotypes that overlap with arrhythmogenic dilated cardiomyopathy and channelopathies. The principal challenges for ARVC/D diagnosis include the following: earlier detection of the disease, particularly in cases of focal right ventricular involvement; differential diagnosis from other arrhythmogenic diseases affecting the right ventricle; and the development of new objective electrocardiographic and imaging criteria for diagnosis. This review provides an update on the diagnosis of ARVC/D, focusing on the contribution of emerging imaging techniques, such as echocardiogram/magnetic resonance imaging strain measurements or computed tomography scanning, new electrocardiographic parameters, and high-throughput sequencing.

The Maastricht-Duke bridge: An era of mentoring in clinical research - A model for mentoring in clinical research - A tribute to Dr. Galen Wagner

OBJECTIVE

With the passing of Dr. Galen Wagner, an exceptional collaboration between Maastricht University Medical Center, The Netherlands, and Duke Clinical Research Institute, USA, has come to an end. This article focuses on the background of what Galen coined the Maastricht-Duke bridge (MD-bridge), its merits, limitations and development throughout the years, and his special role.

METHODS

Between 2004 and 2015, 23 Maastricht University medical students and post-graduate students were enrolled in the 4-month research elective, mentored by Galen and the Maastricht co-mentor. They were asked to complete a survey about their MD-bridge experience.

RESULTS

Sixteen out of the 23 students responded. None but 1 participant had prior research experience. Following their MD bridge-program most participants published 1 or more manuscripts and/or presented their research in an international setting. They felt they had full responsibility as a leader of their project with all participants developing meaningful skills useful in their current job. Fourteen out of 16 would recommend the MD-bridge experience to others. Participants considered the program of great value for their personal growth and independence, giving a feeling of achievement. In addition, for some participants it led to careers in foreign countries including medical practice and research, or obtaining PhDs.

CONCLUSIONS

With Galen's impressive career of mentoring students, including the 23 MD-bridge participants, he has left behind an amazing concept of self-development in research and personal life. The successes of the MD-bridge prove that it is possible for students to be young investigators during or just after medical school with the potential to contribute to developing meaningful skills and noteworthy careers. Collaborations between international universities, such as the MD-bridge, are feasible and should be embraced by other institutions.

Cell junctions in the specialized conduction system of the heart

Anchoring cell junctions are integral in maintaining electro-mechanical coupling of ventricular working cardiomyocytes; however, their role in cardiomyocytes of the cardiac conduction system (CCS) remains less clear. Recent studies in genetic mouse models and humans highlight the appearance of these cell junctions alongside gap junctions in the CCS and also show that defects in these structures and their components are associated with conduction impairments in the CCS. Here we outline current evidence supporting an integral relationship between anchoring and gap junctions in the CCS. Specifically we focus on (1) molecular and ultrastructural evidence for cell-cell junctions in specialized cardiomyocytes of the CCS, (2) genetic mouse models specifically targeting cell-cell junction components in the heart which exhibit CCS conduction defects and (3) human clinical studies from patients with cell-cell junction-based diseases that exhibit CCS electrophysiological defects.