Vena cava izquierda persistente, inusual anatomía para la resincronización cardíaca: experiencia de implante y posterior cambio de generador / Unusual persistent left vena cava, anatomic implications for cardiac resynchronization: implant experience and subsequent generator change

Introducción: La presencia de una vena cava superior izquierda persistente, durante el implante de electrodos endocavitarios para la resincronización cardíaca, representa una anomalía poco habitual de gran relevancia, que puede presentarse de forma inesperada durante el abordaje venoso superior habitual. Planteando desafíos técnicos en su implante y dudas sobre su eficacia o seguridad a corto y largo plazo; existiendo aislados casos publicados. Caso clínico: Presentamos un caso complejo con esta inusual anomalía llevado a implante de este dispositivo de forma exitosa, con funcionamiento normal durante su seguimiento de 7 años, llevado posteriormente a cambio de generador. Conclusiones: La vena cava superior izquierda persistente es la anomalía del retorno venoso cardiaco más frecuente, aunque su prevalencia es baja, presenta una gran relevancia en el implante y posicionamiento de electrodos endocavitarios necesarios para la terapia de resincronización cardiaca. Existe una evidencia creciente sobre su factibilidad y seguridad a corto y largo plazo a pesar de sus dificultades técnicas asociadas.

Introduction: The presence of a persistent left superior vena cava, during the implantation of endocavitary electrodes for cardiac resynchronization, represents an unusual anomaly of great relevance, which can occur unexpectedly during the usual superior venous approach. It constitutes a technical challenge in your implant and doubts about its effectiveness or safety in the short and long term. There are isolated published cases. We present a complex case with this unusual anomaly that led to successful implantation of this device, with a normal functio during its 7-year follow-up It was followed by uneventul generator change. Conclusions: Persistent left superior vena cava is the most common cardiac venous return anomaly. Although its prevalence is low, it is of great relevance in the implantation and positioning of endocavitary electrodes necessary for cardiac resynchronization therapy. There is growing evidence about its feasibility and safety in the short and long term despite.

Improved all-cause mortality with left bundle branch area pacing compared to biventricular pacing in cardiac resynchronization therapy: a meta-analysis.

BACKGROUND: Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative pacing strategy to biventricular pacing (BIVP) in cardiac resynchronization therapy (CRT). We aimed to assess the impact of LBBAP vs. BIVP on all-cause mortality and heart failure (HF)-related hospitalization in patients undergoing CRT. METHODS: Studies comparing LBBAP and BIVP for CRT in patients with HF with reduced left ventricular ejection fraction (LVEF) were included. The coprimary outcomes were all-cause mortality and HF-related hospitalization. Secondary outcomes included procedural and fluoroscopy time, change in QRS duration, and change in LVEF. RESULTS: Thirteen studies (12 observational and 1 RCT, n = 3239; LBBAP = 1338 and BIVP = 1901) with a mean follow-up duration of 25.8 months were included. Compared to BIVP, LBBAP was associated with a significant absolute risk reduction of 3.2% in all-cause mortality (9.3% vs 12.5%, RR 0.7, 95% CI 0.57-0.86, p < 0.001) and an 8.2% reduction in HF-related hospitalization (11.3% vs 19.5%, RR 0.6, 95% CI 0.5-0.71, p < 0.00001). LBBAP also resulted in reductions in procedural time (mean weighted difference- 23.2 min, 95% CI - 42.9 to - 3.6, p = 0.02) and fluoroscopy time (- 8.6 min, 95% CI - 12.5 to - 4.7, p < 0.001) as well as a significant reduction in QRS duration (mean weighted difference:- 25.3 ms, 95% CI - 30.9 to - 19.8, p < 0.00001) and a greater improvement in LVEF of 5.1% (95% CI 4.4-5.8, p < 0.001) compared to BIVP in the studies that reported these outcomes. CONCLUSION: In this meta-analysis, LBBAP was associated with a significant reduction in all-cause mortality as well as HF-related hospitalization when compared to BIVP. Additional data from large RCTs is warranted to corroborate these promising findings.

Response predictors to cardiac resynchronization therapy in chronic heart failure: a 10-year-cardiovascular center experience.

BACKGROUND: Cardiac resynchronization therapy (CRT) has been established as an effective therapy for heart failure with reduced ejection fraction. Randomized clinical trials have shown its impact on mortality and HF hospitalizations, as well as improvement of symptoms and quality of life. OBJECTIVES: Finding clinical, electrocardiographic, and echocardiographic variables that may predict the response to cardiac resynchronization therapy (CRT). METHODS: We performed a single-center, observational, analytic, and retrospective study that included 102 patients with heart failure (HF) diagnosis who underwent CRT according to guideline-directed therapy from January 2010 to April 2020 in a third-level center. CRT response was defined as an improvement of New York Heart Association functional class in at least 1 category associated with a recovery of ≥ 5% in the left ventricular ejection fraction (LVEF). RESULTS: Our study population was 102 patients of which 61 (59.8%) were men. The mean age at HF diagnosis was 54 ± 18.7 years. Ischemic heart disease was the etiology in 37 (36.3%) cases. Fifty-one (50%) patients were classified as responders. Responders had wider QRS, and lower LVEF and right ventricular fractional area change at baseline. After CRT, responders had a greater reduction of QRS duration, and improvement in LVEF, global longitudinal strain, and echocardiographic dyssynchrony parameters. Multivariate regression analysis showed that left bundle branch block (LBBB), left ventricular end-diastolic volume (LVEDV), tricuspid annular plane systolic excursion (TAPSE), and baseline difference of pre-ejection periods were predictors of a positive response to CRT in this population. CONCLUSIONS: LBBB, TAPSE, LVEDV, and pre-ejection time difference are independent variables that can predict adequate response to CRT.

ANTECEDENTES: La terapia de resincronización cardíaca (TRC) se ha establecido como una terapia efectiva para la insuficiencia cardíaca con fracción de eyección reducida. Ensayos clínicos aleatorizados han demostrado su impacto en la mortalidad y hospitalizaciones por insuficiencia cardíaca, así como la mejora de los síntomas y la calidad de vida. OBJETIVOS: Determinar las variables clínicas, electrocardiográficas y ecocardiográficas que puedan predecir la respuesta a la terapia de resincronización cardíaca (TRC). MÉTODO: Estudio unicéntrico, observacional, analítico, retrospectivo, que incluyó 102 pacientes con diagnóstico de IC sometidos a TRC y terapia dirigida por guías, de enero de 2010 a abril de 2020, en un centro de tercer nivel. La respuesta a TRC fue definida como mejoría de la clase funcional de la New York Heart Association en al menos 1 categoría, asociado con una recuperación ≥ 5% en la fracción de expulsión del ventrículo izquierdo (FEVI). RESULTADOS: Incluimos a 102 pacientes, 61 (59.8%) fueron hombres. El promedio de edad al diagnóstico de IC fue 54 ± 18.7 años. La cardiopatía isquémica fue la etiología en 37 (36.3%) pacientes. 51 (50%) pacientes, fueron clasificados como respondedores. Los respondedores presentaron QRS amplio, menor FEVI y menor fracción de acortamiento del ventrículo derecho al inicio del estudio. Después de la TRC, los respondedores tuvieron una mayor reducción en la duración del QRS, mejoría en la FEVI, strain longitudinal global y parámetros de disincronía ecocardiográfica. El análisis de regresión multivariado mostró que el bloqueo de rama izquierdo (BRI), el volumen telediastólico del ventrículo izquierdo (VTDVI) la excursión sistólica del plano anular tricuspídeo (TAPSE) y la diferencia basal del período expulsivo fueron predictores de respuesta positiva a TRC. CONCLUSIONES: BRI, TAPSE, VTDVI y la diferencia basal de períodos preexpulsivos son variables independientes que predicen respuesta adecuada a TRC.

Conduction system pacing versus biventricular pacing in heart failure with reduced ejection fraction: a systematic review and meta-analysis of randomized controlled trials

Conduction system pacing (CSP) has emerged as a promising alternative to biventricular pacing (BVP) heart failure patients with reduced ejection fraction (HFrEF) and ventricular dyssynchrony, but its benefits are still uncertain. In this study, we aim to evaluate clinical outcomes of CSP versus BVP for cardiac resynchronization in patients with HFrEF. PubMed, Scopus, and Cochrane databases were searched for randomized controlled trials (RCTs) comparing CSP to BVP for resynchronization therapy in patients with HFrEF. Heterogeneity was examined with I2 statistics. A random-effects model was used for all outcomes. We included 7 RCTs with 408 patients, of whom 200 (49%) underwent CSP. Compared to biventricular pacing, CSP resulted in a significantly greater reduction in QRS duration (MD -13.34 ms; 95% CI -24.32 to -2.36, p=0.02; I2=91%) and NYHA functional class (SMD -0.37; 95% CI -0.69 to -0.05;p=0.02; I2=41%), and a significant increase in left ventricular ejection fraction (LVEF) (MD 2.06%; 95% CI 0.16 to 3.97; p=0.03; I2=0%). No statistical difference was noted for LVESV (SMD -0.51 mL; 95% CI -1.26 to 0.24; p=0.18; I2=83%), lead capture threshold (MD -0.08 V; 95% CI -0.42 to 0.27; p=0.66; I2=66%), and procedure time (MD 5.99 min; 95% CI -15.91 to 27.89; p=0.59; I2=79%). These findings suggest that CSP may have electrocardiographic, echocardiographic, and symptomatic benefits over biventricular pacing for patients with HFrEF requiring cardiac resynchronization.

Left Bundle Branch Pacing vs Left Ventricular Septal Pacing vs Biventricular Pacing for Cardiac Resynchronization Therapy.

BACKGROUND: Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are considered to be acceptable as LBBAP strategies. Differences in clinical outcomes between LBBP and LVSP are yet to be determined. OBJECTIVES: The purpose of this study was to compare the outcomes of LBBP vs LVSP vs BIVP for CRT. METHODS: In this prospective multicenter observational study, LBBP was compared with LVSP and BIVP in patients undergoing CRT. The primary composite outcome was freedom from heart failure (HF)-related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, postprocedural NYHA functional class, and electrocardiographic and echocardiographic parameters. RESULTS: A total of 415 patients were included (LBBP: n = 141; LVSP: n = 31; BIVP: n = 243), with a median follow-up of 399 days (Q1-Q3: 249.5-554.8 days). Freedom from the primary composite outcomes was 76.6% in the LBBP group and 48.4% in the LVSP group (HR: 1.37; 95% CI: 1.143-1.649; P = 0.001), driven by a 31.4% absolute increase in freedom from HF-related hospitalizations (83% vs 51.6%; HR: 3.55; 95% CI: 1.856-6.791; P < 0.001) without differences in all-cause mortality. LBBP was also associated with a higher freedom from the primary composite outcome compared with BIVP (HR: 1.43; 95% CI: 1.175-1.730; P < 0.001), with no difference between LVSP and BIVP. CONCLUSIONS: In patients undergoing CRT, LBBP was associated with improved outcomes compared with LVSP and BIVP, while outcomes between BIVP and LVSP are similar.

Terapia de modulación cardiaca mediante marcapasos para control de la hipertensión arterial refractaria / Cardiac modulation therapy using pacemakers to control refractory arterial hypertension

BREVE DESCRIPCIÓN DE LA TECNOLOGÍA: La terapia de modulación cardiaca (CNT, del inglés Cardiac Neuromodulation Therapy) mediante el sistema Moderato (BackBeat CNT ™) para el tratamiento de la hipertensión arterial, se fundamenta en que, una reducción de la precarga del ventrículo izquierdo al acortar el intervalo auriculoventricular podría disminuir la tensión arterial (TA). Esta reducción artificial de la TA, no obstante, puede ocasionar una respuesta compensatoria de los barorreceptores para recuperar lo que el organismo considera TA "normal", aumentando a corto plazo la actividad simpática, la contractilidad cardiaca, la frecuencia cardiaca y las resistencias periféricas. Para evitar la activación simpática compensatoria, la tecnología de Moderato (Backbeat CNT™) genera una alternancia entre un intervalo auriculoventricular más corto y otro más largo, permitiendo el tratamiento de la hipertensión arterial (HTA) a largo plazo (1). Moderato™ consiste en un marcapasos de doble cámara con respuesta a la frecuencia cardiaca. El sistema genera impulsos de acuerdo a algoritmos que estimulan el corazón en una serie de intervalos auriculoventriculares más cortos (p. ej., 20-80 ms) y más largos (p. ej., 100-180 ms), de tiempo variable. El objetivo es obtener una secuencia de estimulación consistente en 8 a 13 latidos con retraso auriculoventricular más corto, seguidos de 1 a 3 latidos con el retraso auriculoventricular más largo (1). DESCRIPCIÓN DE LA PATOLOGÍA A LA QUE SE APLICA LA TECNOLOGÍA APLICA LA TECNOLOGÍA: El problema de salud al que se dirige esta tecnología es la hipertensión arterial refractaria o resistente. La hipertensión refractaria se define como cifras de PA > 140/90 mm Hg en consulta, en un paciente tratado con tres o más medicamentos antihipertensivos en dosis óptimas (o máximamente toleradas), incluido un diurético y después de excluir la pseudoresistencia (mala técnica de medición de la PA, efecto de bata blanca, incumplimiento y opciones subóptimas en terapia antihipertensiva), así como la hipertensión inducida por sustancias / fármacos y la hipertensión secundaria (5)(6). La hipertensión refractaria se estima que afecta a alrededor de un 5% de las personas hipertensas, (6), constituye uno de los principales factores de riesgo cardiovasculares, asociada a mortalidad prematura (7). Esta mortalidad relacionada con el mal control de la TA se debe fundamentalmente a cardiopatía isquémica, ictus hemorrágico e ictus isquémico. La HTA se asocia también con la aparición de enfermedad arterial periférica, insuficiencia renal y fibrilación auricular (8,9). Evidencia reciente sostiene que la HTA se relaciona también con un aumento de riesgo de deterioro cognitivo y demencia (10,11). La HTA rara vez se produce sola y con frecuencia se agrupa con otros factores de riesgo cardiovascular, como la dislipemia y la intolerancia a la glucosa (12,13). Esta agrupación de riesgo metabólico tiene un efecto multiplicador en el riesgo cardiovascular (14). Aproximadamente el 50% de los pacientes diagnosticados con hipertensión refractaria o resistente tienen pseudoresistencia en lugar de hipertensión resistente verdadera (5) (6). DESARROLLO Y USO DE LA TECNOLOGIA: BackBeat CNT es un tratamiento bioelectrónico en fase II de desarrollo (experimental/pilotaje) diseñado para reducir la presión arterial. Diseñado para aprovechar el hardware estándar del dispositivo de control del ritmo, como el marcapasos de doble cámara, utilizando el mismo procedimiento de implante y las mismas posiciones de los cables, por tanto, compatible con marcapasos estándar como actualización de firmware y ha sido evaluado en estudios piloto en pacientes con hipertensión en los que estaría indicado el implante de marcapasos. En la actualidad, sólo el marcapasos MODERATO®, que presenta las capacidades y características estándar de los marcapasos con desarrollo tecnológico firmemente establecido, incorpora los algoritmos de estimulación BackBeat-CNT y se está utilizando en los ensayos clínicos, por lo que podría estar cercano a la fase III de investigación. IMPORTANCIA SANITARIA DE LA CONDICIÓN CLÍNICA O LA POBLACIÓN A LA QUE SE APLICA: La hipertensión es el trastorno cardiovascular más prevalente en el mundo. Basándonos en la TA medida en consulta (HTA definida como TA ≥ 140/90), según la OMS, la prevalencia a nivel mundial de HTA en adultos de entre 30 y 79 años con hipertensión ha aumentado de 650 millones a 1280 millones en los últimos treinta años (período 1999-2019), dos tercios de los cuales viven en países de ingresos bajos y medios (8). En 2019, se informó que la prevalencia promedio global de hipertensión estandarizada por edad en adultos de 30 a 79 años fue del 34% en hombres y del 32% en mujeres. En los países europeos, la prevalencia es similar, con diferencias entre países y valores inferiores al promedio en los países de Europa occidental y superiores al promedio en los países de Europa del este. (8). En edades más jóvenes (65 años). La PAS aumenta progresivamente con la edad, mientras que la PAD aumenta sólo hasta la edad de 50 a 60 años, seguida de un breve período de estancamiento y una leve disminución posterior. Esto da como resultado un aumento de la presión del pulso (diferencia entre PAS y PAD) con la edad (6). En España, la prevalencia de hipertensión arterial (HTA) en población adulta oscila entre el 33 y el 43%, y aumenta con la edad de tal forma que en mayores de 65 años supera el 60% (39). Un estudio transversal realizado en población adulta en España en 2016 estimó una prevalencia de 42,6 %, mayor en hombres (49,9 %) que en mujeres (37,1 %) y en personas con prediabetes (67,9 %) o con diabetes (79,4 %). Esta prevalencia aumenta con la edad, especialmente a partir de los 60 y 75 años con una prevalencia del 75,4% y 88,7% respectivamente (40,41). Una estimación razonable de la prevalencia de la hipertensión refractaria es que podría afectar aproximadamente al 5% de la población hipertensa general (6) y constituye uno de los principales factores de riesgo cardiovasculares asociados a mortalidad prematura (6) (7). Son pocos los estudios que comunican cifras de incidencia específica para diferentes estratos de edad y sexo. 4Respecto a la incidencia de HTA en la población española se estima alrededor de una incidencia bruta en mujeres y varones, respectivamente, 8,2 ( IC del 95%, 6,7-10,1)y 21,8 (IC del 95%, 18,6-25,4) por 1.000 personas-año. IMPACTO EN SALUD: La HTA se asocia con un alto riesgo de morbilidad y mortalidad cardiovascular. Se estima que es la primera causa de mortalidad en el mundo tanto en hombre como en mujeres. La aplicación de la TMC en paciente con HTA refractaria se basa en el efecto modulador que se obtendría en la precarga del ventrículo izquierdo mediante el ajuste del intervalo auriculoventricular (AV) con un marcapasos bicameral, que a su vez sería determinante en las cifras de TA (2). Los pacientes con HTA refractaria que precisen un marcapasos se podrían beneficiar de una TMC que posibilitaría un mejor control de la TA sin mayores riesgos o intervenciones más allá de los asociados al implante del marcapasos (1,36). Para la elaboración de este informe se seleccionaron 16 referencias bibliográficas, de las cuales fueron finalmente incluidas 8 referencias tras la lectura a texto completo. EFICACIA Y EFECTIVIDAD: La efectividad de la intervención ha sido descrita con variables relacionadas con cambios en cifras de PAS, en 2 de los estudios cambios en la PAS ambulatoria de 24 horas y en PA en consultorio (Neuzil y Kalarus). Todos los pacientes incluidos en los estudios tenían indicación de implante o reemplazo de un marcapasos bicameral. IMPACTO ÉTICO, SOCIAL, LEGAL, POLÍTICO Y CULTURAL DE LA TECNOLOGÍA: El impacto ético, social, legal, político y cultural viene derivado del implante del MP en pacientes con alteraciones del ritmo (tanto primer implante como reemplazo), por tanto, el uso de esta tecnología no tendría un impacto adicional, más aún considerando que la HTA refractaria no tiene otro tratamiento. Desde un punto de vista ético, si en un futuro se observase beneficio en ensayos aleatorizados bien diseñados con un mayor número de pacientes con variables de resultado en morbimortalidad, y se indicase a pacientes con HTA refractaria sin necesidad de MP, los pacientes deben conocer los posibles riesgos relacionados con el implante de un marcapasos. Hay que notar que el dispositivo solo tiene efectividad sobre la presión arterial sistólica y prácticamente sin efecto sobre la diastólica. Por ello, los pacientes a elegir serían hipertensos refractarios con hipertensión sistólica aislada. Además, dado que la respuesta al dispositivo solo se produce en un 85% de los pacientes (frente al 65% en el grupo control) y que solo el 54% tenía una disminución de más de 10 mmHg (frente al 37% del grupo control) los pacientes a elegir para esta terapia deberán tener unas características muy concretas para esperar control de presión arterial evitando generar expectativas que puedan confundir a los pacientes.

Interamerican Society of Cardiology (CIFACAH - ELECTROSIAC)/Latin American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of cardiac resynchronization therapy in heart failure.

Epidemiological studies suggest that approximately half of the patients with heart failure (HF) have reduced ejection fraction, while the other half have normal ejection fraction (EF). Currently, international guidelines consider QRS duration greater than 130 ms, in the presence of ventricular dysfunction (EF < 35%), as a criterion for selecting patients for cardiac resynchronization therapy (CRT). CRT helps restore intraventricular and auriculoventricular synchrony, improving left ventricular (LV) performance, reducing functional mitral regurgitation, and inducing reverse LV remodeling. This is evidenced by increased LV filling time and left ventricular ejection fraction, decreased LV end-diastolic and end-systolic volumes, mitral regurgitation, and septal dyskinesia. Because the mechanisms of dyssynchrony may be heterogeneous, no single measure may accurately predict response to CRT. Finally, CRT has been progressively shown to be safe and feasible, improves functional status and quality of life, reversely remodels the LV, decreases the number of hospitalizations, total mortality in patients with refractory HF, LV dysfunction, and intraventricular conduction disorders; is a pacemaker-based therapy for HF and thanks to current technology, safe remote monitoring of almost all types of cardiac devices is possible and provides useful alerts in clinical practice.

Los estudios epidemiológicos sugieren que aproximadamente la mitad de los pacientes con insuficiencia cardiaca (IC) tiene fracción de eyección reducida, mientras que la otra mitad, fracción de eyección (FE) normal. Actualmente, las guías internacionales consideran la duración de QRS mayor a 130 ms, en presencia de disfunción ventricular (FE < 35%), como criterio para selección de pacientes a terapia de resincronización cardiaca (TRC). La TRC ayuda a restaurar la sincronía intraventricular y auriculoventricular, mejorando el rendimiento del ventrículo izquierdo (VI), reduciendo la regurgitación mitral funcional e induciendo la remodelación inversa del VI. Esto se evidencia en el aumento del tiempo de llenado del VI y la fracción de eyección del VI, la disminución de los volúmenes telediastólico y telesistólico del VI, y la regurgitación mitral y discinesia septal. Como los mecanismos de la disincronía pueden ser heterogéneos, es posible que ninguna medida prediga con exactitud la respuesta a la TRC. Finalmente, la TRC cardiaca ha demostrado progresivamente ser segura y factible, mejora el estado funcional y la calidad de vida, remodela inversamente el VI, disminuye el número de hospitalizaciones, la mortalidad total en pacientes con IC refractaria, la disfunción ventricular izquierda y los trastornos de conducción intraventricular; es una terapia basada en marcapasos para la IC y gracias a la tecnología actual es posible realizar una supervisión remota y segura de casi todos los tipos de dispositivos cardiacos y obtener alertas útiles en la práctica clínica.

Feasibility of physiological pacing rate in cardiac resynchronization therapy.

AIMS: Although cardiac resynchronization therapy (CRT) improves functional capacity in heart failure patients, a blunted heart rate (HR) response remains after treatment. So we aimed to evaluate the feasibility of the physiological pacing rate (PPR) in CRT patients. METHODS: A cohort of 30 clinical mildly symptomatic CRT patients underwent the six-minute walk test (6MWT). During the 6MWT, HR, blood pressure, and maximum walking distance were assessed. The measurements were obtained in a pre to post manner, with CRT at nominal settings and with the physiological phase (CRT PPR), in which HR was increased by 10% above the maximum HR achieved previously. The CRT cohort also comprised a matched control group (CRT CG). In the CRT CG, the 6MWT was repeated after the standard evaluation with no PPR. The evaluations were blinded for patients and for the 6MWT evaluator. RESULTS: During the 6MWT, CRT PPR led to an increase in walking distance of 40.5 m (9.2%; P < 0.0001) when compared with baseline trial. Additionally, CRT PPR increased the maximum walking distance compared with CRT CG 479.3 ± 68.9 m vs. 420.3 ± 44.8 m, respectively, P = 0.001. In the CRT CG, CRT PPR increased the variation in walking distance, compared with baseline trials, respectively 2.40 ± 3.8% vs. 9.25 ± 7.0%, P = 0.007. CONCLUSIONS: In mildly symptomatic CRT patients PPR is feasible, leading to improvements in functional capacity. In this regard, the efficacy of PPR must be confirmed by controlled randomized trials.

A machine learning method integrating ECG and gated SPECT for cardiac resynchronization therapy decision support.

PURPOSE: Cardiac resynchronization therapy (CRT) has been established as an important therapy for heart failure. Mechanical dyssynchrony has the potential to predict responders to CRT. The aim of this study was to report the development and the validation of machine learning models which integrate ECG, gated SPECT MPI (GMPS), and clinical variables to predict patients' response to CRT. METHODS: This analysis included 153 patients who met criteria for CRT from a prospective cohort study. The variables were used to model predictive methods for CRT. Patients were classified as "responders" for an increase of LVEF ≥ 5% at follow-up. In a second analysis, patients were classified as "super-responders" for an increase of LVEF ≥ 15%. For ML, variable selection was applied, and Prediction Analysis of Microarrays (PAM) approach was used to model response while Naïve Bayes (NB) was used to model super-response. These ML models were compared to models obtained with guideline variables. RESULTS: PAM had AUC of 0.80 against 0.72 of partial least squares-discriminant analysis with guideline variables (p = 0.52). The sensitivity (0.86) and specificity (0.75) were better than for guideline alone, sensitivity (0.75) and specificity (0.24). Neural network with guideline variables was better than NB (AUC = 0.93 vs. 0.87) however without statistical significance (p = 0.48). Its sensitivity and specificity (1.0 and 0.75, respectively) were better than guideline alone (0.78 and 0.25, respectively). CONCLUSIONS: Compared to guideline criteria, ML methods trended toward improved CRT response and super-response prediction. GMPS was central in the acquisition of most parameters. Further studies are needed to validate the models.

Left Bundle Branch Area Pacing Versus Biventricular Pacing as Initial Strategy for Cardiac Resynchronization.

BACKGROUND: Left bundle branch area pacing (LBBAP) for cardiac resynchronization therapy (CRT) is an alternative to biventricular pacing (BiVp). OBJECTIVES: The purpose of this study was to compare the outcomes between LBBAP and BiVp as an initial implant strategy for CRT. METHODS: In this prospective multicenter, observational, nonrandomized study, first-time CRT implant recipients with LBBAP or BiVp were included. The primary efficacy outcome was a composite of heart failure (HF)-related hospitalization and all-cause mortality. The primary safety outcomes were acute and long-term complications. Secondary outcomes included postprocedural New York Heart Association functional class and electrocardiographic and echocardiographic parameters. RESULTS: A total of 371 patients (median follow-up of 340 days [IQR: 206-477 days]) were included. The primary efficacy outcome occurred in 24.2% in the LBBAP vs 42.4% in the BiVp (HR: 0.621 [95% CI: 0.415-0.93]; P = 0.021) group, driven by a reduction in HF-related hospitalizations (22.6% vs 39.5%; HR: 0.607 [95% CI: 0.397-0.927]; P = 0.021) without significant difference in all-cause mortality (5.5% vs 11.9%; P = 0.19) or differences in long-term complications (LBBAP: 9.4% vs BiVp: 15.2%; P = 0.146). LBBAP resulted in shorter procedural (95 minutes [IQR: 65-120 minutes] vs 129 minutes [IQR: 103-162 minutes]; P < 0.001) and fluoroscopy times (12 minutes [IQR: 7.4-21.1 minutes] vs 21.7 minutes [IQR: 14.3-30 minutes]; P < 0.001), shorter QRS duration (123.7 ± 18 milliseconds vs 149.3 ± 29.1 milliseconds; P < 0.001), and higher postprocedural left ventricular ejection fraction (34.1% ± 12.5% vs 31.4% ± 10.8%; P = 0.041). CONCLUSIONS: LBBAP as an initial CRT strategy resulted in a lower risk of HF-related hospitalizations compared to BiVp. A reduction in procedural and fluoroscopy times, shorter paced QRS duration, and improvements in left ventricular ejection fraction compared with BiVp were observed.

Feasibility of Left Ventricle Lead Implantation in Cardiac Resynchronization Therapy Guided by Gated SPECT and Ventricular Remodeling. / Viabilidade do Implante de Eletrodo Ventricular Esquerdo na Terapia de Ressincronização Cardíaca Guiada por Gated SPECT e Remodelamento Ventricular.

BACKGROUND: Cardiac resynchronization therapy (CRT) may benefit patients with advanced heart failure (HF). Abnormal eccentricity index by gated SPECT is related to structural and functional alterations of the left ventricle (LV). OBJECTIVE: The aim of this study is to evaluate the feasibility of LV lead implantation guided by phase analysis and its relationship to ventricular remodeling. METHODS: Eighteen patients with indication for CRT underwent myocardial scintigraphy for implant orientation, and eccentricity and ventricular shape parameters were evaluated. P < 0.05 was adopted as statistical significance. RESULTS: At baseline, most patients were classified as NYHA 3 (n = 12). After CRT, 11 out of 18 patients were reclassified to a lower degree of functional limitation. In addition, patients' quality of life was improved post-CRT. Significant reductions were observed in QRS duration, PR interval, end-diastolic shape index, end-systolic shape index, stroke volume, and myocardial mass post-CRT. The CRT LV lead was positioned concordant, adjacent, and discordant in 11 (61.1%), 5 (27.8%), and 2 (11.1%) patients, respectively. End-systolic and end-diastolic eccentricity demonstrated reverse remodeling post-CRT. CONCLUSIONS: LV lead implantation in CRT guided by gated SPECT scintigraphy is feasible. The placement of the electrode concordant or adjacent to the last segment to contract was a determinant of reverse remodeling.

FUNDAMENTO: A terapia de ressincronização cardíaca (TRC) pode beneficiar pacientes com insuficiência cardíaca (IC) avançada. O índice de excentricidade anormal por gated SPECT está relacionado a alterações estruturais e funcionais do ventrículo esquerdo (VE). OBJETIVO: O objetivo do presente estudo foi avaliar a viabilidade do implante de eletrodos do VE guiado por análise de fase e sua relação com o remodelamento ventricular. MÉTODOS: Dezoito pacientes com indicação de TRC foram submetidos à cintilografia miocárdica para orientar o implante, avaliando-se os parâmetros de excentricidade e forma ventricular. P < 0,05 foi adotado como significância estatística. RESULTADOS: Na linha de base do estudo, a maioria dos pacientes foi classificada como NYHA 3 (n = 12). Após a TRC, 11 dos 18 pacientes foram reclassificados para um menor grau de limitação funcional. Além disso, a qualidade de vida dos pacientes melhorou após a TRC. Foram observadas reduções significativas na duração do QRS, intervalo PR, índice de forma diastólica final, índice de forma sistólica final, volume sistólico e massa miocárdica pós-TRC. O eletrodo do VE da TRC foi posicionado concordante, adjacente e discordante em 11 (61,1%), 5 (27,8%) e 2 (11,1%) pacientes, respectivamente. A excentricidade sistólica e diastólica final demonstrou remodelamento reverso após a TRC. CONCLUSÕES: O implante de eletrodo do VE em TRC guiado por cintilografia gated SPECT é viável. A colocação do eletrodo concordante ou adjacente ao último segmento a se contrair foi um determinante do remodelamento reverso.

Meta-analysis of clinical outcomes in cardiac resynchronisation therapy: his bundle pacing vs biventricular pacing.

INTRODUCTION AND OBJECTIVE: Cardiac resynchronization may treat severe heart failure (HF) with pharmacological optimization, left branch block, and an ejection fraction<35%. However, 30-40% of patients fail therapy. HBP could replace biventricular pacing (BiV). We compared the effectiveness of HBP versus BiV in HF patients. METHODS: We searched PubMed, Embase, and Cochrane for studies on QRS, left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) functional class, left ventricular end-systolic volume (LVESV), and 6-minute walk test. RESULTS: Six publications included 774 patients (mean [± standard deviation] age: 66.9 [14.0] years; 484 (62.5%) were males; 408 [52.71%] underwent HBP; the mean follow-up was 6-12 months. The HBP group had a higher QRS reduction in the meta-analysis (median: -17.54 [-20.46, -14.62]; I2 = 89%). LVEF showed a median of 8.48 (7.55, 9.41) and I2 of 98%, with a higher mean in HBP. The LVESV median was -18.89 (-30.03, -7.75) and I2 was 0%, and the HBP group had a lower mean. HBP had a lower NYHA functional class (median= -0.20 [-0.28, -0.12]). CONCLUSION: After implantation, HBP demonstrated bigger QRS shortening, increased LVEF, lower LVES volume, and lower NYHA class than BiV pacing.

Cardiac resynchronization therapy in acute heart failure and left bundle-branch block in a real-life registry.

Objectives: To determine the prevalence, characteristics, timing of implementation and prognosis of patients with left bundle branch block (LBBB) and acute heart failure (AHF) treated with cardiac resynchronization therapy (CRT) in a real-life registry. Methods: We analysed the characteristics of patients with AHF and LBBB at the time of inclusion in the EAHFE (Epidemiology Acute Heart Failure Emergency) cohort to determine the indication for CRT, the timing of implementation and its impact on 10-year all-cause mortality. Results: 729 patients with a median age of 82 years and there was a high burden of comorbidities and functional dependence. The median left-ventricle ejection fraction (LVEF) was 40%. Forty-six (6%) patients were treated with CRT at some point during follow-up, with a median time of delay for CRT implementation of 960 (IQR=1,147 days) and at least 108 more untreated patients fulfilled criteria for CRT. Patients receiving CRT were younger, had different comorbidities, less functional dependence (higher Barthel index) and lower LVEF values. The median follow-up was 5.7 years (95% CI: 5.6-5.8) and CRT was not associated with changes in 10-year mortality (adjusted HR 1.33, 95% CI: 0.72-2.48; p-value 0.4). When compared with untreated patients fulfilling criteria for CRT, very similar results were observed (adjusted HR 1.34, 95% CI: 0.67-2.68). Conclusions: CRT implementation was delayed and underused in patients with AHF and LBBB. Under these circumstances, CRT is not associated with a reduction in all-cause mortality in the long term.

Objetivos: Determinar la prevalencia, características, momento de implantación y pronóstico de los pacientes con bloqueo de rama izquierda del haz de His (BRIHH) e insuficiencia cardiaca aguda (ICA) tratados con terapia de resincronización cardiaca (TRC) en un registro real. Métodos: Se analizaron las características de los pacientes con ICA y BRIHH en el momento de su inclusión en la cohorte EAHFE (Epidemiology Acute Heart Failure Emergency) para determinar la indicación de TRC, el momento de implantación y su impacto en la mortalidad por cualquier causa a 10 años. Resultados: 729 pacientes con una mediana de edad de 82 años con una elevada carga de comorbilidades y dependencia funcional. La mediana de la fracción de eyección del ventrículo izquierdo (FEVI) fue del 40%. 46 pacientes (6%) fueron tratados con TRC en algún momento del seguimiento, con una mediana de tiempo de retraso para la implantación de la TRC de 960 dias (IQR=1,147 días) y al menos 108 pacientes no tratados cumplían criterios para TRC. Los pacientes que recibieron TRC eran más jóvenes, tenían comorbilidades diferentes, menor dependencia funcional (índice de Barthel más alto) y valores de FEVI más bajos. La mediana de seguimiento fue de 5.7 años (IC del 95%: 5.6-5.8) y la TRC no se asoció a cambios en la mortalidad a 10 años (HR ajustado: 1.33; IC del 95%: 0.72-2.48; p-valor 0.4). Cuando se comparó con pacientes no tratados que cumplían criterios para TRC, se observaron resultados muy similares (HR ajustado 1.34; IC del 95%: 0.67-2.68). Conclusiones: La implantación de la TRC se retrasó y se infrautilizó en pacientes con ICA y BRIHH. En estas circunstancias, la TRC no se asocia a una reducción de la mortalidad por cualquier causa a largo plazo.

Predictive Ability of Cardiopulmonary Exercise Test Parameters in Heart Failure Patients with Cardiac Resynchronization Therapy. / Capacidade Preditiva dos Parâmetros do Teste de Esforço Cardiopulmonar em Pacientes com Insuficiência Cardíaca em Terapia de Ressincronização Cardíaca.

BACKGROUND: There is evidence suggesting that a peak oxygen uptake (pVO2) cut-off of 10ml/kg/min provides a more precise risk stratification in cardiac resynchronization therapy (CRT) patients. OBJECTIVE: To compare the prognostic power of several cardiopulmonary exercise testing (CPET) parameters in this population and assess the discriminative ability of the guideline-recommended pVO2cut-off values. METHODS: Prospective evaluation of consecutive heart failure (HF) patients with left ventricular ejection fraction ≤40%. The primary endpoint was a composite of cardiac death and urgent heart transplantation (HT) in the first 24 follow-up months, and was analysed by several CPET parameters for the highest area under the curve (AUC) in the CRT group. A survival analysis was performed to evaluate the risk stratification provided by several different cut-offs. p values <0.05 were considered significant. RESULTS: A total of 450 HF patients, of which 114 had a CRT device. These patients had a higher baseline risk profile, but there was no difference regarding the primary outcome (13.2% vs 11.6%, p =0.660). End-tidal carbon dioxide pressure at anaerobic threshold (PETCO2AT)had the highest AUC value, which was significantly higher than that of pVO2in the CRT group (0.951 vs 0.778, p =0.046). The currently recommended pVO2cut-off provided accurate risk stratification in this setting (p <0.001), and the suggested cut-off value of 10 ml/min/kg did not improve risk discrimination in device patients (p =0.772). CONCLUSION: PETCO2ATmay outperform pVO2's prognostic power for adverse events in CRT patients. The current guideline-recommended pVO2 cut-off can precisely risk-stratify this population.

FUNDAMENTO: Há evidências sugerindo que um corte do pico de consumo de oxigênio (pVO2) de 10ml/kg/min fornece uma estratificação de risco mais precisa em pacientes com Terapia de Ressincronização Cardíaca (TRC). OBJETIVO: Comparar o poder prognóstico de vários parâmetros do teste cardiopulmonar de exercício (TCPE) nesta população e avaliar a capacidade discriminativa dos valores de corte de pVO2 recomendados pelas diretrizes. MÉTODOS: Avaliação prospectiva de uma série consecutiva de pacientes com insuficiência cardíaca (IC) com fração de ejeção do ventrículo esquerdo ≤40%. O desfecho primário foi um composto de morte cardíaca e transplante cardíaco urgente (TC) nos primeiros 24 meses de acompanhamento, e foi analisado por vários parâmetros do TCPE para a maior área sob a curva (AUC) no grupo TRC. Uma análise de sobrevida foi realizada para avaliar a estratificação de risco fornecida por vários pontos de corte diferentes. Valores de p < 0,05 foram considerados significativos. RESULTADOS: Um total de 450 pacientes com IC, dos quais 114 possuíam aparelho de TRC. Esses pacientes apresentaram um perfil de risco basal mais alto, mas não houve diferença em relação ao desfecho primário (13,2% vs 11,6%, p = 0,660). A pressão expiratória de dióxido de carbono no limiar anaeróbico (PETCO2AT) teve o maior valor de AUC, que foi significativamente maior do que o de pVO2 no grupo TRC (0,951 vs 0,778, p = 0,046). O valor de corte de pVO2 atualmente recomendado forneceu uma estratificação de risco precisa nesse cenário (p <0,001), e o valor de corte sugerido de 10 ml/min/kg não melhorou a discriminação de risco em pacientes com dispositivos (p = 0,772). CONCLUSÃO: A PETCO2AT pode superar o poder prognóstico do pVO2 para eventos adversos em pacientes com TRC. O ponto de corte de pVO2 recomendado pelas diretrizes atuais pode estratificar precisamente o risco dessa população.

Vectorcardiography-derived index allows a robust quantification of ventricular electrical synchrony.

Alteration of muscle activation sequence is a key mechanism in heart failure with reduced ejection fraction. Successful cardiac resynchronization therapy (CRT), which has become standard therapy in these patients, is limited by the lack of precise dyssynchrony quantification. We implemented a computational pipeline that allows assessment of ventricular dyssynchrony by vectorcardiogram reconstruction from the patient's electrocardiogram. We defined a ventricular dyssynchrony index as the distance between the voltage and speed time integrals of an individual observation and the linear fit of these variables obtained from a healthy population. The pipeline was tested in a 1914-patient population. The dyssynchrony index showed minimum values in heathy controls and maximum values in patients with left bundle branch block (LBBB) or with a pacemaker (PM). We established a critical dyssynchrony index value that discriminates electrical dyssynchronous patterns (LBBB and PM) from ventricular synchrony. In 10 patients with PM or CRT devices, dyssynchrony indexes above the critical value were associated with high time to peak strain standard deviation, an echocardiographic measure of mechanical dyssynchrony. Our index proves to be a promising tool to evaluate ventricular activation dyssynchrony, potentially enhancing the selection of candidates for CRT, device configuration during implantation, and post-implant optimization.

Clinical and gated SPECT MPI parameters associated with super-response to cardiac resynchronization therapy.

PURPOSE: We sought to evaluate the behavior of cardiac mechanical synchrony as measured by phase SD (PSD) derived from gated MPI SPECT (gSPECT) in patients with super-response after CRT and to evaluate the clinical and imaging characteristics associated with super-response. METHODS: 158 subjects were evaluated with gSPECT before and 6 months after CRT. Patients with an improvement of LVEF > 15% and NYHA class I/II or reduction in LV end-systolic volume > 30% and NYHA class I/II were labeled as super-responders (SR). RESULTS: 34 patients were classified as super-responders (22%) and had lower PSD (32° ± 17°) at 6 months after CRT compared to responders (45° ± 24°) and non-responders 46° ± 28° (P = .02 for both comparisons). Regression analysis identified predictors independently associated with super-response to CRT: absence of previous history of CAD (odds ratio 18.7; P = .002), absence of diabetes mellitus (odds ratio 13; P = .03), and history of hypertension (odds ratio .2; P = .01). CONCLUSION: LV dyssynchrony after CRT implantation, but not at baseline, was significantly better among super-responders compared to non-super-responders. The absence of diabetes, absence of CAD, and history of hypertension were independently associated with super-response after CRT.

Sensor hemodinámico de resincronización cardiaca en el tratamiento de la insuficiencia cardiaca avanzada / Hemodynamic sensor for cardiac resynchronization in the treatment of advanced heart failure

NOMBRE DE LA TECNOLOGÍA: Sensor hemodinámico de resincronización cardiaca en el tratamiento de la insuficiencia cardiaca (IC) avanzada sintomática refractaria al tratamiento farmacológico (SonR™). BREVE DESCRIPCIÓN DE LA TECNOLOGÍA: SonRTM es un microacelerómetro incorporado en la punta del electrodo auricular SonRtip de los dispositivos de resincronización cardíaca PlatiniumSonR CRT-D™ (Figura 1) y se trata de un sistema de optimización de la terapia de resincronización cardiaca (TRC). En el vídeo cuya URL señalamos a continuación se puede ver más detenidamente cómo funciona la tecnología objeto del informe: https://www.youtube.com/watch?v=XvCYpXbxkbA POBLACIÓN DIANA: Pacientes con insuficiencia (IC) cardiaca sintomática a pesar de contar con un tratamiento farmacológico óptimo, con fracción de eyección del ventrículo izquierdo (FEVI) reducida y QRS ancho, en los que está indicada la TRC. DESCRIPCIÓN DEL PROBLEMA DE SALUD AL QUE SE APLICA LA TECNOLOGÍA: El pro