P Wave Dispersion: a valuable non-invasive marker of vulnerability to atrial arrhythmias

The prolongation of intraatrial and interatrial conduction time and the non-homogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation (AF). Previous studies have demonstrated that individuals with clinical history of paroxysmal AF show a significantly increased P wave duration in 12-lead surface electrocardiograms (ECG) and signal-averaged ECG recordings. The inhomogeneous and discontinuous atrial conduction in patients with atrial arrhythmias has been studied, during the last years, with a new ECG index, P wave dispersion. P wave dispersion is defined as the difference between the longest and the shortest P wave duration recorded from multiple different surface ECG leads. Extensive clinical evaluation of P wave dispersion has been performed in the assessment of the risk for AF in patients without apparent heart disease, in hypertensive patients, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. P wave dispersion has proven to be a sensitive and specific ECG predictor of AF in the various clinical settings. However, the methodology used for the calculation of P wave dispersion has not been standardized so far and more efforts to improve the reliability and reproducibility of P wave dispersion measurements are needed. In conclusion, P wave dispersion constitutes a significant contribution to the field of non-invasive electrocardiology and seems to be quite promising in the field of AF prediction

Achievement of Right Ventricular Pacing by Use of a Long Guiding Catheter in a Hemodialysis Patient Presenting Significant Tortuosity of Vasculature

Increased vascular calcification and tortuosity are rather common in end-stage renal failure patients who are on hemodialysis. It renders manipulation of catheters and performance of percutaneous transluminal interventions more difficult than expected. Such vascular alterations may be evident in large veins and pose significant difficulties in placement of pacing leads as shown in our case. To overcome such difficulties, we demonstrated in this patient case that long guiding catheters may be of particular value

Ενδοκαρδιακή μέσω Καθετήρα Κατάλυση με Υψίσυχνο Ρεύμα σε Μετεμφραγματικό Ασθενή με Ηλεκτρική Θύελλα πριν από την Εμφύτευση Απινιδωτού: Μακροχρόνια Πορεία και Έκβαση

Περιγράφεται η περίπτωση ενός ασθενούς, 66 ετών, που παρουσιάσθηκε με πολλαπλά επεισόδια εμμένουσας μονόμορφης κοιλιακής ταχυκαρδίας 30 και 14 έτη μετά δύο εμφράγματα του κατωτέρου και του προσθίου τοιχώματος του μυοκαρδίου. Αφού η ηλεκτρική θύελλα κατεστάλη με ένα μεικτό σχήμα τριπλής αντιαρρυθμικής αγωγής, ο ασθενής υπεβλήθη σε ενδοκαρδιακή κατάλυση της αρρυθμιογόνου εστίας με τη βοήθεια του ηλεκτροανατομικού συστήματος χαρτογράφησης στο ηλεκτροφυσιολογικό εργαστήριο. Ακολούθησε η εμφύτευση ενός αντιταχυκαρδιακού βηματοδότου απινιδωτού που στους επακόλουθους 30 μήνες παρακολούθησης κινητοποιήθηκε αθόρυβα σε ένα μοναδικό στιγμιότυπο αντιταχυκαρδιακής βηματοδότησης

Atrial Flutter Ablation Using a Three-Dimensional Electroanatomical Mapping System

Typical atrial flutter ablation is usually performed conventionally, by creating a line across the cavotricuspid isthmus under fluoroscopic guidance. In this article, we present the case of a middle-aged male who was submitted to flutter ablation through use of a three-dimensional electroanatomical mapping system, yielding highly accurate and pedantic images.

Cardiac Resynchronization Therapy and Proarrhythmia: Weathering the Storm

In patients with significant left ventricular (LV) dysfunction and congestive heart failure despite optimal medical therapy, implantation of cardiac resynchronization therapy-defibrillator (CRT-D) devices has been shown to improve symptoms and diminish ventricular tachyarrhythmia susceptibility.We describe the case of a patient with dilated cardiomyopathy who developed ventricular tachycardia storm (VTS) one month after the implantation of a CRT-D device. VTS was initially controlled with pharmacotherapy, allowing the patient to continue with biventricular pacing. Two months later the patient was readmitted due to multiple episodes of polymorphic ventricular tachycardia. VTS was refractory to various intravenous antiarrhythmic drugs and it was finally controlled only when LV pacing was turned off.In patients with heart failure treated with CRT-D, VTS can occur and is best managed by turning off LV pacing. Our report raises an important and concerning issue of biventricular pacing causing ‘proarrhythmia’ in rare instances

Cardiac Resynchronisation Therapy and Cellular Bioenergetics: Effects Beyond Chamber Mechanics

Cardiac resynchronisation therapy is a cornerstone in the treatment of advanced dyssynchronous heart failure. However, despite its widespread clinical application, precise mechanisms through which it exerts its beneficial effects remain elusive. Several studies have pointed to a metabolic component suggesting that, both in concert with alterations in chamber mechanics and independently of them, resynchronisation reverses detrimental changes to cellular metabolism, increasing energy efficiency and metabolic reserve. These actions could partially account for the existence of responders that improve functionally but not echocardiographically. This article will attempt to summarise key components of cardiomyocyte metabolism in health and heart failure, with a focus on the dyssynchronous variant. Both chamber mechanics-related and -unrelated pathways of resynchronisation effects on bioenergetics – stemming from the ultramicroscopic level – and a possible common underlying mechanism relating mechanosensing to metabolism through the cytoskeleton will be presented. Improved insights regarding the cellular and molecular effects of resynchronisation on bioenergetics will promote our understanding of non-response, optimal device programming and lead to better patient care

Decreased Deceleration Capacity of Heart Rate Detects Heart Failure Patients at Risk for Malignant Ventricular Arrhythmias

BACKGROUND: Deceleration capacity (DC) of the heart rate has proved an independent predictor of total mortality in post-myocardial infarction (post-MI) patients but it is unknown whether DC predicts the arrhythmic risk as well. OBJECTIVE: Our aim was to investigate whether DC can predict the arrhythmic sudden cardiac death (SCD) surrogate in patients with heart failure (HF). PATIENTS AND METHODS: We prospectively screened 145 HF patients with electrocardiogram (ECG), signal averaged ECG, echocardiography, and 24-hour Holter ECG. After 41.2 months, patients were divided into high (n=43) and low risk (n=102) groups according to three arrhythmic surrogates: clinical ventricular tachyarrhythmia (ventricular tachycardia -VT/ ventricular fibrillation-VF) (n=18), appropriate activation of the implantable cardioverter defibrillator (ICD) device (n=23) and confirmed SCD (n=2). RESULTS: High risk patients had impaired DC with significantly lower values (3.2±1.8 ms vs 4.0±2.1 ms, p=0.025). In the Cox regression analysis model adjusted for age, gender, diabetes, left ventricular ejection fraction (LVEF), filtered QRS, QTc, nonsustained VT episode(s) ≥ 1/24 h, ventricular premature beats ≥240/24 and DC, DC emerged as an important SCD surrogate predictor with a hazard ratio of 0.804, (95% confidence intervals-CI: 0.671- 0.963, p = 0.018). The cutoff point of DC≤3.352 ms (median) presented a hazard ratio of 2.885 (95% CI: 1.342 - 6.199, p=0.007, log rank test: p=0.003) for SCD surrogate. CONCLUSION: Decreased DC was found to be an important and independent SCD surrogate predictor. The cutoff point of DC≤3.352 ms detects HF patients at increased arrhythmic risk.

Mobile health applications for managing atrial fibrillation for healthcare professionals and patients: a systematic review

Aims A plethora of mobile health applications (m-health apps) to support healthcare are available for both patients and healthcare professionals (HCPs) but content and quality vary considerably and few have undergone formal assessment. The aim is to systematically review the literature on m-health apps for managing atrial fibrillation (AF) that examine the impact on knowledge of AF, patient and HCP behaviour, patients’ quality-of-life, and user engagement. Methods and results MEDLINE, EMBASE, CINAHL, and PsychInfo were searched from 1 January 2005 to 5 September 2019, with hand-searching of clinical trial registers and grey literature. Studies were eligible for inclusion if they reported changes in any of the following: (i) knowledge of AF; (ii) provider behaviour (e.g. guideline adherence); (iii) patient behaviour (e.g. medication adherence); (iv) patient quality-of-life; and (v) user engagement. Two reviewers independently assessed articles for eligibility. A narrative review was undertaken as included studies varied widely in their design, interventions, comparators, and outcomes. Seven studies were included; six m-health apps aimed at patients and one at HCPs. Mobile health apps ranged widely in design, features, and method of delivery. Four studies reported patient knowledge of AF; three demonstrated significant knowledge improvement post-intervention or compared to usual care. One study reported greater HCP adherence to oral anticoagulation guidelines after m-health app implementation. Two studies reported on patient medication adherence and quality-of-life; both showed improved quality-of-life post-intervention but only one observed increased adherence. Regarding user engagement, five studies reported patient perspectives on usability, three on acceptability, and one on feasibility; overall all m-health apps were rated positively. Conclusion Mobile health apps demonstrate improvements in patient knowledge, behaviour, and quality of life. Studies formally evaluating the impact of m-health on HCP behaviour are scarce and larger-scale studies with representative patient cohorts, appropriate comparators, and longer-term assessment of the impact of m-health apps are warranted

ESC Working Group on e-Cardiology Position Paper: Use of Commercially Available Wearable Technology for Heart Rate and Activity Tracking in Primary and Secondary Cardiovascular Prevention

Commercially available health technologies such as smartphones and smartwatches, activity trackers and eHealth applications, commonly referred to as wearables, are increasingly available and used both in the leisure and healthcare sector for pulse and fitness/ activity tracking. The aim of the Position Paper is to identify specific barriers and knowledge gaps for the use of wearables, in particular for heart rate and activity tracking, in clinical cardiovascular healthcare to support their implementation into clinical care. The widespread use of heart rate and fitness tracking technologies provides unparalleled opportunities for capturing physiological information from large populations in the community, which has previously only been available in patient populations in the setting of healthcare provision. The availability of low-cost and high-volume physiological data from the community also provides unique challenges. While the number of patients meeting healthcare providers with data from wearables is rapidly growing, there are at present no clinical guidelines on how and when to use data from wearables in primary and secondary prevention. Technical aspects of heart rate tracking especially during activity need to be further validated. How to analyze, translate, and interpret large datasets of information into clinically applicable recommendations needs further consideration. While the current users of wearable technologies tend to be young, healthy and in the higher sociodemographic strata, wearables could potentially have a greater utility in the elderly and higher risk population. Wearables may also provide a benefit through increased health awareness, democratization of health data and patient engagement. Use of continuous monitoring may provide opportunities for detection of risk factors and disease development earlier in the causal pathway, which may provide novel applications in both prevention and clinical research. However, wearables may also have potential adverse consequences due to unintended modification of behaviour, uncertain use and interpretation of large physiological data, a possible increase in social inequality due to differential access and technological literacy, challenges with regulatory bodies and privacy issues. In the present position paper, current applications as well as specific barriers and gaps in knowledge are identified and discussed in order to support the implementation of wearable technologies from gadget-ology into clinical cardiology