Integrated hybrid Raman/fiber Bragg grating interrogation scheme for distributed temperature and point dynamic strain measurements

We propose and experimentally demonstrate the feasibility of an integrated hybrid optical fiber sensing interrogation technique that efficiently combines distributed Raman-based temperature sensing with fiber Bragg grating (FBG)-based dynamic strain measurements. The proposed sensing system is highly integrated, making use of a common optical source/receiver block and exploiting the advantages of both (distributed and point) sensing technologies simultaneously. A multimode fiber is used for distributed temperature sensing, and a pair of FBGs in each discrete sensing point, partially overlapped in the spectral domain, allows for temperature-independent discrete strain measurements. Experimental results report a dynamic strain resolution of 7.8  nε/√Hz within a full range of 1700 με and a distributed temperature resolution of 1°C at 20 km distance with 2.7 m spatial resolution

The interaction of QRS duration with cardiac magnetic resonance derived scar and mechanical dyssynchrony in systolic heart failure:Implications for cardiac resynchronization therapy

Background: Trials using echocardiographic mechanical dyssynchrony (MD) parameters in narrow QRS patients have shown a negative response to CRT. We hypothesized MD in these patients may relate to myocardial scar rather than electrical dyssynchrony. Methods: We determined the prevalence of cardiac magnetic resonance (CMR) derived measures of MD in 130 systolic heart failure patients with both broad (≥130 ms - BQRS) and narrow QRS duration (<130 ms - NQRS). We assessed whether late gadolinium enhancement derived scar might explain the presence of MD amongst narrow QRS patients. Dyssynchrony was calculated on the basis of a systolic dyssynchrony index (SDI). Results: Fifty-nine patients (45%) had a NQRS and the remaining had QRS ≥130 ms (BQRS group). 25% of NQRS patients had MD based on SDI. In all narrow and broad QRS patients with MD there was a significantly lower scar volume than those without MD (7.4 ± 10.5% vs 13.7 ± 13.3% vs. p < 0.01). This was the case in the BQRS group with a significantly lower scar burden in patients with MD (5.0 ± 7.7% vs 15.4 ± 15.6%, p < 0.01). Notably in the NQRS group this difference was absent with an equal scar burden in patients with MD 13.3 ± 13.9% and without MD 12.5 ± 11%, p = 0.92. Conclusions: 25% of patients with systolic heart failure and a NQRS (<130 ms) have CMR derived mechanical dyssynchrony. Our findings suggest MD in this group may be secondary to myocardial scar rather than electrical dyssynchrony and therefore not amenable to correction by CRT. This may give insight into non-response and potential harm from CRT in this group. Keywords: Narrow QRS, Cardiac resynchronization therapy, Dyssynchrony, Cardiac magnetic resonance imagin

Endocardite sur sonde de stimulation cardiaque (nouveaux outils diagnostiques et thérapeutiques)

L'endocardite sur sonde de pacemaker (PM) est associée à un risque de morbi-mortalité important. Cette prise en charge constiture une situation fréquente en cardiologie. Ces 2 études illustrent la possibilité de nouveaux outils diagnostiques et thérapeutiques. Certains patients (pts) implantés d'un PM peuvent être hospitalisés pour un tableau de fièvre d'origine inconnu (FUO), malgré de multiples investigations diagnostiques (échographie trans-œsophagienne...), à la recherche d'endocardite sur sonde. Cette étude pilote à partir de 10 pts implantés d'un PM et présentant un tableau de FUO, étudie l'intérêt de la tomographie par émission de positron avec le traceur 18F-fluorodeoxyglucose (FDG-PET/CT scan), comme nouvel outil diagnostique d'endocardite sur sonde, dans certains cas difficiles. Le FDG-PET/CT a montré une hyperfixation des sondes chez 6 pts avec tableau de FUO. L'extraction complète du PM a été réalisée chez ces 6 pts : la culture de PM était positive, confirmant le diagnostic d'endocardite sur sonde. Les 4 autres pts avec tableau de FUO n'ont pas eu d'extraction de PM, et n'ont pas présenté au cours du suivi de tableau actif d'endocardite sur sonde. Chez les pts dépendants de la stimulation cardiaque, et présentant un tableau d'infection de PM, l'extraction complète est à réaliser. Cependant, le maintien d'une stimulation ventriculaire (V) permanente reste difficile. Souvent, un système temporaire de stimulation V est mis en place, préalablement à l'extraction, suivi de la réimplantation du PM dans un site controlatéral avec stimulation endocardique (après plusieurs jours d'antibiothérapie). Afin de réduire la durée de cette prise en charge et d'éviter tout risque de réinfection, nous proposons une étude de faisabilité avec la réimplantation épicardique de 2 sondes V extra-vasculaires par voie sous-gastrique, suivie de l'extraction percutanée du PM infecté, au cours d'une même procédure chirurgicale. Les 100 pts ont eu un suivi de 12 mois.BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Percolation as a mechanism to explain atrial fractionated electrograms and reentry in a fibrosis model based on imaging data

Complex fractionated atrial electrograms (CFAEs) have long been associated with proarrhythmic alterations in atrial structure or electrophysiology. Structural alterations disrupt and slow smoothly propagating wavefronts, leading to wavebreaks and electrogram (EGM) fractionation, but the exact nature and characteristics for arrhythmia remain unknown. Clinically, in atrial fibrillation (AF) patients, increases in frequency, whether by pacing or fibrillation, increase EGM fractionation and duration, and reentry can occur in relation with the conduction disturbance. Recently, percolation has been proposed as an arrhythmogenic mechanism, but its role in AF has not been investigated

Implantation of a cardiac resynchronization therapy and defibrillation system using a robotic approach

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Noninvasive Assessment of LV Contraction Patterns Using CMR to Identify Responders to CRT

ObjectivesType II activation describes the U-shaped electrical activation of the left ventricle (LV) with a line of block in patients with left bundle branch block (LBBB). We sought to determine if a corresponding pattern of contraction could be identified using cardiac magnetic resonance (CMR) cine imaging and whether this predicted response to cardiac resynchronization therapy (CRT).BackgroundU-shaped LV electrical activation in LBBB has been shown to predict favorable response to CRT. It is not known if the degree of electromechanical coupling is such that the same is true for LV contraction patterns.MethodsA total of 52 patients (48% ischemic) scheduled for CRT implantation prospectively underwent pre-implantation CMR cine analysis using endocardial contour tracking software to generate time−volume curves and contraction propagation maps. These were analyzed to assess the contraction sequence of the LV. The effect of contraction pattern on CRT response in terms of reverse remodeling (RR) and clinical parameters (New York Heart Association functional class, 6-min walk distance and Heart Failure Questionnaire score) was assessed at 6 months.ResultsTwo types of contraction pattern were identified; homogenous spread from septum to lateral wall (type I, n = 27) and presence of block with a subsequent U-shaped contraction pattern (type II, n = 25). Rates of RR in those with a type 2 pattern were significantly greater at 6 months (80% vs. 26%, p < 0.001) as was mean increase in 6-min walk distance (126 ± 106 m vs. 55 ± 60 m; p = 0.004).ConclusionsCine CMR can identify a U-shaped pattern of contraction which predicts increased echocardiographic and clinical response rates to CRT in patients with LBBB

Alternative to left ventricular lead implantation through the coronary sinus: 1-year experience with a minimally invasive and robotically guided approach

Aims Left ventricular (LV) lead implantation through the coronary sinus (CS) can be limited and sometimes not possible- alternative approaches are needed. Minimally invasive, robotically guided LV lead implantation has major advantages, but there are little published data about the short- and long-term follow-ups, in terms of feasibility, safety, electrical performance, and impact on clinical outcome. Methods and results A total of 21 heart failure patients underwent robotically guided LV lead implantation using the Da Vinci Robotic System. Indications were failed implant with conventional approach through the CS (n = 16) and non-response to conventional cardiac resynchronization therapy (n = 5). During the procedure, the entire LV free wall was exposed through 3 transthoracic ports (10 mmdiameter each) allowing ample choice of stimulation site and the ability to implant 2 LV leads via a Y connector. Patients were prospectively followed up for 1 year. The two LV leads were successfully implanted in all patients. No peri-procedural complications were observed. After a mean stay in the intensive care unit of 1.2+4 days, the 21 patients were hospitalized in the EP department for 6.7+2.9 days. Acute LV thresholds were excellent (1.0 V+0.6/0.4 ms) and stayed stable at 1-year follow-up (1.5 V+0.6/0.4 ms, P = 0.21). Four patients demonstrated an increased threshold (.2 V/0.4 ms). There was no phrenic nerve stimulation. After 12 months, in the failed implant group, 69% of the patients were echocardiographic and clinical responders. Conclusion The robotic approach was feasible, safe, and minimally invasive. Accordingly, robotically guided LV lead implantation seems to offer a new alternative when conventional approaches are not suitable.SCOPUS: ar.jinfo:eu-repo/semantics/publishe