Valoración y optimización del intervalo aurículo-ventricular en pacientes con marcapasos bicamerales y buena función ventricular por método optométrico

En este estudio se evalúan los cambios observados en la presión de pulso no invasiva medida a través de un método optométrico en relación a las modificaciones de intervalo aurículo-ventricular sensado y estimulado en pacientes con marcapasos bicamerales. Se intentó obtener el intervalo aurículo-ventricular óptimo en ambas situaciones. Existen marcadas diferencias entre la performance cardíaca de acuerdo a si la aurícula o los ventrículos son sensados o estimulados.Facultad de Ciencias Médica

Usefulness of ventricular sense response in last-generation cardiac resynchronization therapy devices

Objectives: High percentages of pacing were associated to maximal symptomatic and mortality benefit from cardiac resynchronization therapy (CRT). Loss of CRT pacing is linked to intrinsic ventricular activation preceding biventricular pacing (BiV), as it occurs in patients with atrial fibrillation (AF). Last generation CRT devices incorporate the ventricular sense response (VSR) mechanism to maintain biventricular pacing in patients with atrial arrhythmias. This work aimed to characterize electrical dyssynchrony differences among baseline, BiV and VSR pacing, and determine whether the VSR mode is as beneficial as the BiV mode in terms of electrical dyssynchrony. Methods: Thirty-two patients implanted with CRT devices were retrospectively studied. All patients presented non-ischemic dilated myocardiopathy and complete left bundle branch block (LBBB). Every patient went through baseline, BiV and VSR pacing while recording the 12‑lead ECG. Electrical dyssynchrony was assessed by a dyssynchrony index (DIn) obtained from correlation analysis on the 12‑lead ECG. Results: When comparing with baseline, VSR pacing improved QRS duration (178 ± 22 ms vs 158 ± 43 ms, baseline vs VSR, p < 0.05) and so did BiV pacing (178 ± 22 ms vs 142 ± 20 ms, baseline vs BiV, p < 0.05). However, electrical dyssynchrony only improved at BiV pacing (2.86 ± 0.6 vs 0.54 ± 0.8, baseline vs BiV, p < 0.05) while VSR showed average DIn values similar to those at baseline. Conclusions: VSR pacing did not improve the electrical synchrony while did shorten QRS duration in this sample population. Therefore, VSR paced beats would fall in the category of inefficient BiV and may not be the preferred alternative in patients with CRT and AF.Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; ArgentinaFil: Ortega, Daniel F.. Clínica San Camilo; ArgentinaFil: Logarzo, Emilio. Clínica San Camilo; ArgentinaFil: Mangani, Nicolás. Clínica San Camilo; ArgentinaFil: Paolucci, Analía. Clínica San Camilo; Argentin

Abordaje eléctrico para mejorar la activación ventricular izquierda durante estimulación del ventrículo derecho

Coronary sinus mapping is commonly used to evaluate left atrial activation. Herein, we propose to use it to assess which right ventricular pacing modality produces the shortest left ventricular activation times (R-LVtime) and the narrowest QRS widths. Three study groups were defined: 54 controls without intraventricular conduction disturbances; 15 patients with left bundle branch block, and 15 patients with right bundle branch block. Left ventricular activation times and QRS widths were evaluated among groups under sinus rhythm, right ventricular apex, right ventricular outflow tract and high output septal zone (SEPHO). Left ventricular activation time was measured as the time elapsed from the surface QRS onset to the most distal left ventricular deflection recorded at coronary sinus. During the above stimulation modalities, coronary sinus mapping reproduced electrical differences that followed mechanical differences measured by tissue doppler imaging. Surprisingly, 33% of the patients with left bundle branch block displayed an early left ventricular activation time, suggesting that these patients would not benefit from resynchronization therapy. SEPHO improved QRS widths and left ventricular activation times in all groups, especially in patients with left bundle branch block, in whom these variables became similar to controls. Left ventricular activation time could be useful to search the optimum pacing site and would also enable detection of non-responders to cardiac resynchronization therapy. Finally, SEPHO resulted the best pacing modality, because it narrowed QRS-complexes and shortened left ventricular activations of patients with left bundle branch block and preserved the physiological depolarization of controls.El mapeo del seno coronario se utiliza comúnmente para evaluar la activación de la aurícula izquierda. Aquí, investigamos su utilidad para evaluar qué modalidad de estimulación ventricular derecha produce los menores tiempos de activación ventricular izquierda (R-LVtime). Se definieron tres grupos: 54 controles; 15 pacientes con bloqueo de rama izquierda y 15 con bloqueo de rama derecha. El ancho de QRS y los tiempos de activación fueron evaluados en cada grupo bajo las siguientes modalidades: ritmo sinusal, ápex del ventrículo derecho, tracto de salida del ventrículo derecho y alta salida en septum (SEPHO). El R-LVtime se midió como el tiempo transcurrido desde el inicio del QRS de superficie y la deflexión ventricular izquierda más distal del seno coronario. Durante las distintas modalidades de estimulación, el mapeo del seno coronario reprodujo diferencias eléctricas acompañadas por diferencias mecánicas que fueron evaluadas mediante Tissue Doppler Imaging. El 33% de los pacientes con bloqueo de rama izquierda mostró R-LVtime tempranos, lo que sugiere que estos pacientes no se beneficiarían con terapia de resincronización. SEPHO mejoró el ancho de QRS y el R-LVtime de todos los grupos, especialmente en los pacientes con bloqueo de rama izquierda. En conclusión, el R-LVtime serviría para identificar el sitio óptimo de estimulación y permitiría detectar ciertos no respondedores a la terapia de resincronización. Además, el SEPHO resultó la mejor modalidad de estimulación porque estrechó el QRS y acortó el R-LVtime de los pacientes con bloqueo de rama izquierda pero no alteró la despolarización fisiológica de los controles.Fil: Bonomini, Maria Paula. Universidad de Buenos Aires. Facultad de Ingenieria. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderon; ArgentinaFil: Ortega, Daniel Felipe. Hospital Universitario Austral; ArgentinaFil: Barja, Luis Dante. Hospital Universitario Austral; ArgentinaFil: Mangani, Nicolas. Hospital Universitario Austral; ArgentinaFil: Paolucci, Analia. Hospital Universitario Austral; ArgentinaFil: Logarzo, Emilio. Hospital Universitario Austral; Argentin

ECG parameters to predict left ventricular electrical delay

Aims: Left ventricular (LV) dyssynchrony lengthens the left ventricular electrical delay (LVED), measured from QRS onset to the first peak of the LV electrogram. We constructed an ECG model to predict LVED noninvasively. Methods: Intrapatient LVED was measured during a baseline vs nonselective His bundle pacing (nHBP) protocol. This setup provided paired synchronic/non-synchronic LVEDs, allowing intrapatient comparisons. Crosscorrelation of leads II and V 6 was accomplished and extracted features together with age and gender fed a linear mixed effects model to predict LVED. Results: Hemodynamic increments were consistent with LVED advances under nHBP in a subset of 17 patients (dP/dt max , baseline: 938.82 ± 241.95 mm Hg/s vs nHBP: 1034.94 ± 253.63 mm Hg/s, p = 6.24e-4). The inclusion of the area under V 6 (A V 6 ) and the time shift of R-peaks obtained from the crosscorrelation signal (Cor S ) grouped by patient significantly improved LVED estimation with respect to the model based only on QRS duration, age and gender (p = 1.7e-5). Conclusions: Interlead ECG changes explained LVED, providing clues about the electrical impulse conduction within the left ventricle noninvasively.Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires; ArgentinaFil: Ortega, Daniel F.. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Barja, Luis D.. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Logarzo, Emilio. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Mangani, Nicolás. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Paolucci, Analía. Clínica San Camilo; Argentina. Hospital Universitario Austral; Argentin

Non-selective His bundle pacing with a biphasic waveform: enhancing septal resynchronization

Aims: His bundle pacing has shown to prevent detrimental effects from right ventricular apical pacing (RVA) and proved to resynchronize many conduction disturbances cases. However, the extent of His bundle pacing resynchronization is limited. An optimized stimulation waveform could expand this limit when implemented in His bundle pacing sets. In this work, we temporarily implemented RVA and Non-selective His bundle pacing with a biphasic anodal-first waveform (AF-nHB) and compared their effects against sinus rhythm (SR). Methods and results: Fifteen patients referred for electrophysiologic study with conduction disturbances, cardiomyopathy and ejection fraction below 35% were enrolled for the study. The following acute parameters were measured: QRS duration, left ventricular activation (RLVT), time of isovolumic contraction (IVCT), ejection fraction (EF), and dP/dtmax. QRS duration and RLVT decreased markedly under AF-nHB (SR: 169 ± 34 ms vs. nHB: 116 ± 31 ms, P < 0.0005) while RVA significantly increased QRS duration (SR: 169 ms vs. RVA: 198 ms, P < 0.05) and did not change RLVT (P = NS). Consistently, IVCT moderately decreased under AF-nHB (SR: 238 ms vs. RVA: 184 ms, P < 0.05 vs. SR) and dP/dtmax showed a 93.35 [mmHg] average increase under AF-nHB against SR. Also, T-wave inversions were observed during AF-nHB immediately after SR and RVA pacing suggesting the occurrence of cardiac memory. Conclusions: AF-nHB corrected bundle branch blocks in patients with severe conduction disturbances, even in those with dilated cardiomiopathy, outstanding from RVA. Also, the occurrence of cardiac memory during AF-nHB turned up as an observational finding of this study.Fil: Ortega, Daniel F.. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Barja, Luis D.. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Logarzo, Emilio. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Mangani, Nicolas. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Paolucci, Analia. Clínica San Camilo; Argentina. Hospital Universitario Austral; ArgentinaFil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentin

Novel implant technique for septal pacing. A noninvasive approach to nonselective his bundle pacing

Background: His Bundle pacing (HBP) preserves native ventricular activation through His Purkinje. Unfortunately, most current techniques for HBP implants require sheaths, special leads, and an electrophysiology setup for electrogram recording. Methods: We developed an implantation technique guided by a non-invasive assessment of left ventricular electrical delay (LVED) as a measure of intraventricular dyssynchrony. The objective was to evaluate the usefulness and safety of this technique for implants of pacemakers and ICDs with right ventricular septal pacing (RVSP) using conventional screw-in leads and compare it with a reduced group of HBP (n = 32) guided by His potential mapping. 208 patients eligible for ventricular stimulation were implanted. Conventional screw-in leads were used in all cases. To ensure mechanical stability, stylets required a slight reshaping at the tip Results: RVSP normalized electrical activity in patients with conduction disease, producing NS-HBP-like patterns. The parameters evaluated during implantation for the RVSP group were better than those of HBP and remained constant at a twelve months follow-up. In proportion, the number of dislodgments and the need for CRT upgrade was lower for RVSP than for HBP. Additionally, fluoroscopy time was significantly reduced in the RVSP group. Conclusions: This technique successfully guided RVSP implants in a non-invasive way and represents a simple alternative to the implant of a cardiac stimulation device.Fil: Ortega, Daniel. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Logarzo, Emilio. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Barja, Luis. No especifíca;Fil: Paolucci, Analía. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Mangani, Nicolás. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Mazzetti, Eduardo. No especifíca;Fil: Bonomini, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentin