Dispersión espacial de los tiempos de activación y repolarización asociada a diferentes modos de estimulación cardiaca

En pacientes con indicación de marcapasos permanente se aplican distintos tipos de estimulación ventricular. Los denominados fisiológicos estimulan el sistema de conducción cardiaca induciendo una activación fisiológica eficiente. Entre estos se encuentran la estimulación selectiva del haz de His (HBP selectiva, sHBP, y HBP no selectiva, nsHBP, por sus siglas en inglés) y las estimulaciones selectiva y no selectiva de la rama izquierda (sLBBP y nsLBBP) Otras regiones cardiacas que también suelen estimularse mediante el marcapasos son el septo del ventrículo izquierdo (LVSP) o del ventrículo derecho (RVSP) y el ápex del ventrículo derecho (RVAP). En este trabajo se analizaron 695 electrocardiogramas de muy alta frecuencia (UHF-ECG) obtenidos de 176 pacientes con complejo QRS estrecho y con indicación de marcapasos. Se caracterizaron los tiempos de activación (TA) y de repolarización (TR) y se agruparon en tres regiones según las derivaciones en las que se evaluaron (R1: derivaciones V1-V2; R2: V3-V4; R3: V5-V6). Globalmente en la población, las estimulaciones sHBP, nsLBBP y LVSP proporcionaron los valores de AT y RT más similares a los obtenidos durante ritmo espontáneo. Los valores absolutos de las medias para las diferencias R1-R2 y R3-R2 en TA resultaron menores a 3, 16 y 10 ms para sHBP, nsLBBP y LVSP, respectivamente, con respecto al ritmo espontáneo. Para TR estas diferencias fueron menores a 11, 34 y 24 ms para sHBP y nsLBBP y LVSP. En conclusión, las estimulaciones HBP, LBBP y LVSP inducen los tiempos de activación y repolarización ventricular más similares a los hallados en ritmo espontáneo en pacientes con conducción fisiológica (QRS estrecho).Este trabajo ha sido realizado con el apoyo de los proyectos PID2019-105674RB-I00, PID2019-104881RB-I00, TED2021-130459B-I00 y la ayuda BES-2017-080587 (Ministerio de Ciencia e Innovación), el proyecto LMP94_21 y el grupo de referencia BSICoS T39-23R (Gobierno de Aragón cofinanciado por el FEDER 2014-2020 “Construyendo Europa desde Aragón”) y el proyecto ERC G.A. 638284 (European Research Council). Los cálculos computacionales se han realizado en la ICTS NANBIOSIS (HPC Unit at University of Zaragoza)

Comparison of UHF-ECG with Other Noninvasive Electrophysiological Mapping Tools for Assessing Ventricular Dyssynchrony

This paper compares Ultra High Frequency ECG (UHF-ECG) with other techniques in the capacity to assess ventricular dyssynchrony. Ventricular dyssynchrony is important to identify patients that qualify for Cardiac Resynchronization Therapy (CRT) and to measure effects of CRT and other pacing therapies.Currently used tools are: duration of the QRS complex in the 12-lead ECG, vectorcardiographically determined QRSarea, ECG belt and ECG imaging. QRS duration is crude, QRSarea has been shown to predict CRT response in three large single center studies, ECG belt is a novel approach using 50-60 body surface electrodes and yields (variation in) activation times. ECG imaging requires cardiothoracic imaging and recordings using 150-250 electrodes and results in images of activation, which are converted into inter and intraventricular AT differences. UHF-ECG requires 12-14 lead ECG but provides two measures: (also) a measure of interventricular dyssynchrony (e-DYS) and a marker of width of the activation wavefront that reflects the contribution of rapid conduction. The latter is a unique feature that appears particularly useful in studies on different modes of physiological pacing

Feasibility and safety of left bundle branch area pacing-cardiac resynchronization therapy in elderly patients

Background Left bundle branch area pacing (LBBAP) is an emerging technique to achieve cardiac resynchronization therapy (CRT), but its feasibility and safety in elderly patients with heart failure with reduced ejection fraction and left bundle branch block is hardly investigated.Methods We enrolled consecutive patients with an indication for CRT comparing pacing parameters and complication rates of LBBAP-CRT in elderly patients (>= 75 years) versus younger patients (< 75 years) over a 6-month follow-up.Results LBBAP was successful in 55/60 enrolled patients (92%), among which 25(45%) were elderly. In both groups, LBBAP significantly reduced the QRS duration (elderly group: 168 +/- 15 ms to 136 +/- 12 ms, p < 0.0001; younger group: 166 +/- 14 ms to 134 +/- 11 ms, p < 0.0001) and improved LVEF (elderly group: 28 +/- 5% to 40 +/- 7%, p < 0.0001; younger group: 29 +/- 5% to 41 +/- 8%, p < 0.0001). The pacing threshold was 0.9 +/- 0.8 V in the elderly group vs. 0.7 +/- 0.5 V in the younger group (p = 0.350). The R wave was 9.5 +/- 3.9 mV in elderly patients vs. 10.7 +/- 2.7 mV in younger patients (p = 0.341). The fluoroscopic (elderly: 13 +/- 7 min vs. younger: 11 +/- 7 min, p = 0.153) and procedural time (elderly: 80 +/- 20 min vs. younger: 78 +/- 16 min, p = 0.749) were comparable between groups. Lead dislodgement occurred in 2(4%) patients, 1 in each group (p = 1.000). Intraprocedural septal perforation occurred in three patients (5%), 2(8%) in the elderly group (p = 0.585). One patient (2%) in the elderly group had a pocket infection.Conclusions LBBAP is a feasible and safe technique for delivering physiological pacing in elderly patients who are candidates for CRT with suitable pacing parameters and low complication rates

Conduction system pacing, a European survey: insights from clinical practice

Aims The field of conduction system pacing (CSP) is evolving, and our aim was to obtain a contemporary picture of European CSP practice. Methods and results A survey was devised by a European CSP Expert Group and sent electronically to cardiologists utilizing CSP. A total of 284 physicians were invited to contribute of which 171 physicians (60.2%; 85% electrophysiologists) responded. Most (77%) had experience with both His-bundle pacing (HBP) and left bundle branch area pacing (LBBAP). Pacing indications ranked highest for CSP were atrioventricular block (irrespective of left ventricular ejection fraction) and when coronary sinus lead implantation failed. For patients with left bundle branch block (LBBB) and heart failure (HF), conventional biventricular pacing remained first-line treatment. For most indications, operators preferred LBBAP over HBP as a first-line approach. When HBP was attempted as an initial approach, reasons reported for transitioning to utilizing LBBAP were: (i) high threshold (reported as >2 V at 1 ms), (ii) failure to reverse bundle branch block, or (iii) > 30 min attempting to implant at His-bundle sites. Backup right ventricular lead use for HBP was low (median 20%) and predominated in pace-and-ablate scenarios. Twelve-lead electrocardiogram assessment was deemed highly important during follow-up. This, coupled with limitations from current capture management algorithms, limits remote monitoring for CSP patients. Conclusions This survey provides a snapshot of CSP implementation in Europe. Currently, CSP is predominantly used for bradycardia indications. For HF patients with LBBB, most operators reserve CSP for biventricular implant failures. Left bundle branch area pacing ostensibly has practical advantages over HBP and is therefore preferred by many operators. Practical limitations remain, and large randomized clinical trial data are currently lacking

Bipolar anodal septal pacing with direct LBB capture preserves physiological ventricular activation better than unipolar left bundle branch pacing

BackgroundLeft bundle branch pacing (LBBP) produces delayed, unphysiological activation of the right ventricle. Using ultra-high-frequency electrocardiography (UHF-ECG), we explored how bipolar anodal septal pacing with direct LBB capture (aLBBP) affects the resultant ventricular depolarization pattern.MethodsIn patients with bradycardia, His bundle pacing (HBP), unipolar nonselective LBBP (nsLBBP), aLBBP, and right ventricular septal pacing (RVSP) were performed. Timing of local ventricular activation, in leads V1–V8, was displayed using UHF-ECG, and electrical dyssynchrony (e-DYS) was calculated as the difference between the first and last activation. Durations of local depolarizations were determined as the width of the UHF-QRS complex at 50% of its amplitude.ResultsaLBBP was feasible in 63 of 75 consecutive patients with successful nsLBBP. aLBBP significantly improved ventricular dyssynchrony (mean −9 ms; 95% CI (−12;−6) vs. −24 ms (−27;−21), ), p ConclusionAlthough aLBBP improved ventricular synchrony and depolarization duration of the septum and RV compared to unipolar nsLBBP, the resultant ventricular depolarization was still less physiological than during HBP.</p